RNA recognition motif (RRM) found in cleavage stimulation factor subunit 2 (CSTF2), cleavage stimulation factor subunit 2 tau variant (CSTF2T) and similar proteins; This subgroup corresponds to the RRM domain of CSTF2, its tau variant and eukaryotic homologs. CSTF2, also termed cleavage stimulation factor 64 kDa subunit (CstF64), is the vertebrate conterpart of yeast mRNA 3'-end-processing protein RNA15. It is expressed in all somatic tissues and is one of three cleavage stimulatory factor (CstF) subunits required for polyadenylation. CstF64 contains an N-terminal RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a CstF77-binding domain, a repeated MEARA helical region and a conserved C-terminal domain reported to bind the transcription factor PC-4. During polyadenylation, CstF interacts with the pre-mRNA through the RRM of CstF64 at U- or GU-rich sequences within 10 to 30 nucleotides downstream of the cleavage site. CSTF2T, also termed tauCstF64, is a paralog of the X-linked cleavage stimulation factor CstF64 protein that supports polyadenylation in most somatic cells. It is expressed during meiosis and subsequent haploid differentiation in a more limited set of tissues and cell types, largely in meiotic and postmeiotic male germ cells, and to a lesser extent in brain. The loss of CSTF2T will cause male infertility, as it is necessary for spermatogenesis and fertilization. Moreover, CSTF2T is required for expression of genes involved in morphological differentiation of spermatids, as well as for genes having products that function during interaction of motile spermatozoa with eggs. It promotes germ cell-specific patterns of polyadenylation by using its RRM to bind to different sequence elements downstream of polyadenylation sites than does CstF64.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17137710  10 IMDKSMRSVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12671   1 ASDRSLRSVFVGNIPYEATEEQLKDIFSEVGPVVSFRLVYDRETGKPKGYGFCEYQDQETALSAMRNLNGYELNGRALRV 80

                ....*
gi 17137710  90 DNACT 94
Cdd:cd12671  81 DNAAS 85

Transcription termination and cleavage factor C-terminal; The C-terminal section of CSTF proteins is a discreet structure is crucial for mRNA 3'-end processing. This domain interacts with Pcf11 and possibly PC4, thus linking CstF2 to transcription, transcriptional termination, and cell growth.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|
gi 17137710   377 DQEKAALIMQVLQLSDEQIAQLPSEQRVSIVMLKEQIAKS 416
Cdd:pfam14304   2 DPGQAELIQQVLQLSEAQIAALPPDQRRSIMELRQQLRRG 41

RNA recognition motif (RRM) found in cleavage stimulation factor subunit 2 (CSTF2), cleavage stimulation factor subunit 2 tau variant (CSTF2T) and similar proteins; This subgroup corresponds to the RRM domain of CSTF2, its tau variant and eukaryotic homologs. CSTF2, also termed cleavage stimulation factor 64 kDa subunit (CstF64), is the vertebrate conterpart of yeast mRNA 3'-end-processing protein RNA15. It is expressed in all somatic tissues and is one of three cleavage stimulatory factor (CstF) subunits required for polyadenylation. CstF64 contains an N-terminal RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a CstF77-binding domain, a repeated MEARA helical region and a conserved C-terminal domain reported to bind the transcription factor PC-4. During polyadenylation, CstF interacts with the pre-mRNA through the RRM of CstF64 at U- or GU-rich sequences within 10 to 30 nucleotides downstream of the cleavage site. CSTF2T, also termed tauCstF64, is a paralog of the X-linked cleavage stimulation factor CstF64 protein that supports polyadenylation in most somatic cells. It is expressed during meiosis and subsequent haploid differentiation in a more limited set of tissues and cell types, largely in meiotic and postmeiotic male germ cells, and to a lesser extent in brain. The loss of CSTF2T will cause male infertility, as it is necessary for spermatogenesis and fertilization. Moreover, CSTF2T is required for expression of genes involved in morphological differentiation of spermatids, as well as for genes having products that function during interaction of motile spermatozoa with eggs. It promotes germ cell-specific patterns of polyadenylation by using its RRM to bind to different sequence elements downstream of polyadenylation sites than does CstF64.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17137710  10 IMDKSMRSVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12671   1 ASDRSLRSVFVGNIPYEATEEQLKDIFSEVGPVVSFRLVYDRETGKPKGYGFCEYQDQETALSAMRNLNGYELNGRALRV 80

                ....*
gi 17137710  90 DNACT 94
Cdd:cd12671  81 DNAAS 85

Hinge domain of cleavage stimulation factor subunit 2; The hinge domain of cleavage stimulation factor subunit 2 proteins, CSTF2, is necessary for binding to the subunit CstF-77 within the polyadenylation complex and subsequent nuclear localization. This suggests that nuclear import of a pre-formed CSTF complex is an essential step in polyadenylation. Accurate and efficient polyadenylation is essential for transcriptional termination, nuclear export, translation, and stability of eukaryotic mRNAs. CSTF2 is an important regulatory subunit of the polyadenylation complex.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17137710   111 ENPYGEPCEP-EDAPELITKTVASLPPEQMYELMKQMKLCIVSNPSEARQMLMLNPQLAYALLQAMVVMRIVDPQQALGM 189
Cdd:pfam14327   1 PLPPGVQLPPgLTAPDAISKTLSSLPPAQLLELLSQMKALAQNNPAQARELLIQNPQLAYALFQALLLMGLVDPDVITSV 80

                  .
gi 17137710   190 L 190
Cdd:pfam14327  81 L 81

RNA recognition motif. (a.k.a. RRM, RBD, or RNP domain); The RRM motif is probably diagnostic of an RNA binding protein. RRMs are found in a variety of RNA binding proteins, including various hnRNP proteins, proteins implicated in regulation of alternative splicing, and protein components of snRNPs. The motif also appears in a few single stranded DNA binding proteins. The RRM structure consists of four strands and two helices arranged in an alpha/beta sandwich, with a third helix present during RNA binding in some cases The C-terminal beta strand (4th strand) and final helix are hard to align and have been omitted in the SEED alignment The LA proteins have an N terminal rrm which is included in the seed. There is a second region towards the C terminus that has some features characteriztic of a rrm but does not appear to have the important structural core of a rrm. The LA proteins are one of the main autoantigens in Systemic lupus erythematosus (SLE), an autoimmune disease.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 17137710    18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDrESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLR 88
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKSIRLVRD-ETGRSKGFAFVEFEDEEDAEKAIEALNGKELGGRELK 70

glycine-rich RNA-binding protein 4; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17137710   18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRVdNACTEKS 97
Cdd:PLN03134  37 LFIGGLSWGTDDASLRDAFAHFGDVVDAKVIVDRETGRSRGFGFVNFNDEGAATAAISEMDGKELNGRHIRV-NPANDRP 115

RNA recognition motif (RRM) found in cleavage stimulation factor subunit 2 (CSTF2), cleavage stimulation factor subunit 2 tau variant (CSTF2T) and similar proteins; This subgroup corresponds to the RRM domain of CSTF2, its tau variant and eukaryotic homologs. CSTF2, also termed cleavage stimulation factor 64 kDa subunit (CstF64), is the vertebrate conterpart of yeast mRNA 3'-end-processing protein RNA15. It is expressed in all somatic tissues and is one of three cleavage stimulatory factor (CstF) subunits required for polyadenylation. CstF64 contains an N-terminal RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a CstF77-binding domain, a repeated MEARA helical region and a conserved C-terminal domain reported to bind the transcription factor PC-4. During polyadenylation, CstF interacts with the pre-mRNA through the RRM of CstF64 at U- or GU-rich sequences within 10 to 30 nucleotides downstream of the cleavage site. CSTF2T, also termed tauCstF64, is a paralog of the X-linked cleavage stimulation factor CstF64 protein that supports polyadenylation in most somatic cells. It is expressed during meiosis and subsequent haploid differentiation in a more limited set of tissues and cell types, largely in meiotic and postmeiotic male germ cells, and to a lesser extent in brain. The loss of CSTF2T will cause male infertility, as it is necessary for spermatogenesis and fertilization. Moreover, CSTF2T is required for expression of genes involved in morphological differentiation of spermatids, as well as for genes having products that function during interaction of motile spermatozoa with eggs. It promotes germ cell-specific patterns of polyadenylation by using its RRM to bind to different sequence elements downstream of polyadenylation sites than does CstF64.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17137710  10 IMDKSMRSVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12671   1 ASDRSLRSVFVGNIPYEATEEQLKDIFSEVGPVVSFRLVYDRETGKPKGYGFCEYQDQETALSAMRNLNGYELNGRALRV 80

                ....*
gi 17137710  90 DNACT 94
Cdd:cd12671  81 DNAAS 85

RNA recognition motif (RRM) domain [Translation, ribosomal structure and biogenesis];

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 17137710  15 MRSVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:COG0724   1 SMKIYVGNLPYSVTEEDLRELFSEYGEVTSVKLITDRETGRSRGFGFVEMPDDEEAQAAIEALNGAELMGRTLKV 75

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 17137710     17 SVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSKFGKVESVRLVRDKETGKSKGFAFVEFESEEDAEKALEALNGKELDGRPLKV 73

RNA recognition motif. (a.k.a. RRM, RBD, or RNP domain); The RRM motif is probably diagnostic of an RNA binding protein. RRMs are found in a variety of RNA binding proteins, including various hnRNP proteins, proteins implicated in regulation of alternative splicing, and protein components of snRNPs. The motif also appears in a few single stranded DNA binding proteins. The RRM structure consists of four strands and two helices arranged in an alpha/beta sandwich, with a third helix present during RNA binding in some cases The C-terminal beta strand (4th strand) and final helix are hard to align and have been omitted in the SEED alignment The LA proteins have an N terminal rrm which is included in the seed. There is a second region towards the C terminus that has some features characteriztic of a rrm but does not appear to have the important structural core of a rrm. The LA proteins are one of the main autoantigens in Systemic lupus erythematosus (SLE), an autoimmune disease.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 17137710    18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDrESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLR 88
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKSIRLVRD-ETGRSKGFAFVEFEDEEDAEKAIEALNGKELGGRELK 70

RNA recognition motif (RRM) found in Helicobacter pylori HP0827 protein and similar proteins; This subfamily corresponds to the RRM of H. pylori HP0827, a putative ssDNA-binding protein 12rnp2 precursor, containing one RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). The ssDNA binding may be important in activation of HP0827.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRVDNA 92
Cdd:cd12399   1 LYVGNLPYSASEEQLKSLFGQFGAVFDVKLPMDRETKRPRGFGFVELQEEESAEKAIAKLDGTDFMGRTIRVNEA 75

RNA recognition motif 2 (RRM2) found in RNA-binding protein 34 (RBM34) and similar proteins; This subfamily corresponds to the RRM2 of RBM34, a putative RNA-binding protein containing two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). Although the function of RBM34 remains unclear currently, its RRM domains may participate in mRNA processing. RBM34 may act as an mRNA processing-related protein.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 17137710  17 SVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRnLNGYEIGGRTLRV 89
Cdd:cd12395   1 SVFVGNLPFDIEEEELRKHFEDCGDVEAVRIVRDRETGIGKGFGYVLFKDKDSVDLALK-LNGSKLRGRKLRV 72

RNA recognition motif 3 (RRM3) found found in type I polyadenylate-binding proteins; This subfamily corresponds to the RRM3 of type I poly(A)-binding proteins (PABPs), highly conserved proteins that bind to the poly(A) tail present at the 3' ends of most eukaryotic mRNAs. They have been implicated in the regulation of poly(A) tail length during the polyadenylation reaction, translation initiation, mRNA stabilization by influencing the rate of deadenylation and inhibition of mRNA decapping. The family represents type I polyadenylate-binding proteins (PABPs), including polyadenylate-binding protein 1 (PABP-1 or PABPC1), polyadenylate-binding protein 3 (PABP-3 or PABPC3), polyadenylate-binding protein 4 (PABP-4 or APP-1 or iPABP), polyadenylate-binding protein 5 (PABP-5 or PABPC5), polyadenylate-binding protein 1-like (PABP-1-like or PABPC1L), polyadenylate-binding protein 1-like 2 (PABPC1L2 or RBM32), polyadenylate-binding protein 4-like (PABP-4-like or PABPC4L), yeast polyadenylate-binding protein, cytoplasmic and nuclear (PABP or ACBP-67), and similar proteins. PABP-1 is an ubiquitously expressed multifunctional protein that may play a role in 3' end formation of mRNA, translation initiation, mRNA stabilization, protection of poly(A) from nuclease activity, mRNA deadenylation, inhibition of mRNA decapping, and mRNP maturation. Although PABP-1 is thought to be a cytoplasmic protein, it is also found in the nucleus. PABP-1 may be involved in nucleocytoplasmic trafficking and utilization of mRNP particles. PABP-1 contains four copies of RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), a less well conserved linker region, and a proline-rich C-terminal conserved domain (CTD). PABP-3 is a testis-specific poly(A)-binding protein specifically expressed in round spermatids. It is mainly found in mammalian and may play an important role in the testis-specific regulation of mRNA homeostasis. PABP-3 shows significant sequence similarity to PABP-1. However, it binds to poly(A) with a lower affinity than PABP-1. PABP-1 possesses an A-rich sequence in its 5'-UTR and allows binding of PABP and blockage of translation of its own mRNA. In contrast, PABP-3 lacks the A-rich sequence in its 5'-UTR. PABP-4 is an inducible poly(A)-binding protein (iPABP) that is primarily localized to the cytoplasm. It shows significant sequence similarity to PABP-1 as well. The RNA binding properties of PABP-1 and PABP-4 appear to be identical. PABP-5 is encoded by PABPC5 gene within the X-specific subinterval, and expressed in fetal brain and in a range of adult tissues in mammalian, such as ovary and testis. It may play an important role in germ cell development. Moreover, unlike other PABPs, PABP-5 contains only four RRMs, but lacks both the linker region and the CTD. PABP-1-like and PABP-1-like 2 are the orthologs of PABP-1. PABP-4-like is the ortholog of PABP-5. Their cellular functions remain unclear. The family also includes the yeast PABP, a conserved poly(A) binding protein containing poly(A) tails that can be attached to the 3'-ends of mRNAs. The yeast PABP and its homologs may play important roles in the initiation of translation and in mRNA decay. Like vertebrate PABP-1, the yeast PABP contains four RRMs, a linker region, and a proline-rich CTD as well. The first two RRMs are mainly responsible for specific binding to poly(A). The proline-rich region may be involved in protein-protein interactions.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDrESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRVDNA 92
Cdd:cd12380   4 VYVKNFGEDVDDDELKELFEKYGKITSAKVMKD-DSGKSKGFGFVNFENHEAAQKAVEELNGKELNGKKLYVGRA 77

RNA recognition motif (RRM) found in cold inducible RNA binding protein (CIRBP), RNA binding motif protein 3 (RBM3) and similar proteins; This subfamily corresponds to the RRM domain of two structurally related heterogenous nuclear ribonucleoproteins, CIRBP (also termed CIRP or A18 hnRNP) and RBM3 (also termed RNPL), both of which belong to a highly conserved cold shock proteins family. The cold shock proteins can be induced after exposure to a moderate cold-shock and other cellular stresses such as UV radiation and hypoxia. CIRBP and RBM3 may function in posttranscriptional regulation of gene expression by binding to different transcripts, thus allowing the cell to response rapidly to environmental signals. However, the kinetics and degree of cold induction are different between CIRBP and RBM3. Tissue distribution of their expression is different. CIRBP and RBM3 may be differentially regulated under physiological and stress conditions and may play distinct roles in cold responses of cells. CIRBP, also termed glycine-rich RNA-binding protein CIRP, is localized in the nucleus and mediates the cold-induced suppression of cell cycle progression. CIRBP also binds DNA and possibly serves as a chaperone that assists in the folding/unfolding, assembly/disassembly and transport of various proteins. RBM3 may enhance global protein synthesis and the formation of active polysomes while reducing the levels of ribonucleoprotein complexes containing microRNAs. RBM3 may also serve to prevent the loss of muscle mass by its ability to decrease cell death. Furthermore, RBM3 may be essential for cell proliferation and mitosis. Both, CIRBP and RBM3, contain an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), that is involved in RNA binding, and C-terminal glycine-rich domain (RGG motif) that probably enhances RNA-binding via protein-protein and/or protein-RNA interactions. Like CIRBP, RBM3 can also bind to both RNA and DNA via its RRM domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 17137710  16 RSVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRVDNA 92
Cdd:cd12449   1 GKLFVGGLSFDTNEQSLEEVFSKYGQISEVVVVKDRETQRSRGFGFVTFENPDDAKDAMMAMNGKSLDGRQIRVDQA 77

RNA recognition motif 1 (RRM1) found in RNA-binding protein 28 (RBM28) and similar proteins; This subfamily corresponds to the RRM1 of RBM28 and Nop4p. RBM28 is a specific nucleolar component of the spliceosomal small nuclear ribonucleoproteins (snRNPs), possibly coordinating their transition through the nucleolus. It specifically associates with U1, U2, U4, U5, and U6 small nuclear RNAs (snRNAs), and may play a role in the maturation of both small nuclear and ribosomal RNAs. RBM28 has four RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an extremely acidic region between RRM2 and RRM3. The family also includes nucleolar protein 4 (Nop4p or Nop77p) encoded by YPL043W from Saccharomyces cerevisiae. It is an essential nucleolar protein involved in processing and maturation of 27S pre-rRNA and biogenesis of 60S ribosomal subunits. Nop4p also contains four RRMs.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 17137710  17 SVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRVDNA 92
Cdd:cd12413   1 TLFVRNLPYDTTDEQLEELFSDVGPVKRCFVVKDKGKDKCRGFGYVTFALAEDAQRALEEVKGKKFGGRKIKVELA 76

RNA recognition motif 3 (RRM3) found in RNA-binding protein 28 (RBM28) and similar proteins; This subfamily corresponds to the RRM3 of RBM28 and Nop4p. RBM28 is a specific nucleolar component of the spliceosomal small nuclear ribonucleoproteins (snRNPs), possibly coordinating their transition through the nucleolus. It specifically associates with U1, U2, U4, U5, and U6 small nuclear RNAs (snRNAs), and may play a role in the maturation of both small nuclear and ribosomal RNAs. RBM28 has four RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an extremely acidic region between RRM2 and RRM3. The family also includes nucleolar protein 4 (Nop4p or Nop77p) encoded by YPL043W from Saccharomyces cerevisiae. It is an essential nucleolar protein involved in processing and maturation of 27S pre-rRNA and biogenesis of 60S ribosomal subunits. Nop4p also contains four RRMs.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17137710  16 RSVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLN------GYEIGGRTLRV 89
Cdd:cd12415   1 KTVFIRNLSFDTTEEDLKEFFSKFGEVKYARIVLDKDTGHSKGTAFVQFKTKESADKCIEAANdesedgGLVLDGRKLIV 80

                ...
gi 17137710  90 DNA 92
Cdd:cd12415  81 SLA 83

RNA recognition motif 1 (RRM1) found in chloroplastic plastid-specific 30S ribosomal protein 2 (PSRP-2) and similar proteins; PSRP-2, also called chloroplastic 30S ribosomal protein 2, or chloroplastic small ribosomal subunit protein cS22, is a component of the chloroplast ribosome (chloro-ribosome), a dedicated translation machinery responsible for the synthesis of chloroplast genome-encoded proteins, including proteins of the transcription and translation machinery and components of the photosynthetic apparatus. It binds single strand DNA (ssDNA) and RNA in vitro. It exhibits RNA chaperone activity and regulates negatively resistance responses to abiotic stresses during seed germination (e.g. salt, dehydration, and low temperature) and seedling growth (e.g. salt). The family also includes Nicotiana sylvestris chloroplastic 33 kDa ribonucleoprotein (NsCP33) and Arabidopsis thaliana chloroplastic 31 kDa ribonucleoprotein (AtCP31A). NsCP33 may be involved in splicing and/or processing of chloroplast RNA's. AtCP31A, also called RNA-binding protein 1/2/3 (AtRBP33), or RNA-binding protein CP31A, or RNA-binding protein RNP-T, or RNA-binding protein cp31, is required for specific RNA editing events in chloroplasts and stabilizes specific chloroplast mRNAs, as well as for normal chloroplast development under cold stress conditions by stabilizing transcripts of numerous mRNAs under these conditions. CP31A may modulate telomere replication through RNA binding domains. Members in this family contain two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The model corresponds to the first RRM motif.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd21609   2 LYVGNIPRNVTSEELAKIFEEAGTVEIAEVMYDRYTGRSRGFGFVTMGSVEDAKAAIEKLNGTEVGGREIKV 73

RNA recognition motif (RRM) found in Saccharomyces cerevisiae nucleolar protein 6 (Nop6) and similar proteins; This subfamily corresponds to the RRM of Nop6, also known as Ydl213c, a component of 90S pre-ribosomal particles in yeast S. cerevisiae. It is enriched in the nucleolus and is required for 40S ribosomal subunit biogenesis. Nop6 is a non-essential putative RNA-binding protein with two N-terminal putative nuclear localisation sequences (NLS-1 and NLS-2) and an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). It binds to the pre-rRNA early during transcription and plays an essential role in pre-rRNA processing.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQEtALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12400   3 LFVGNLPYDTTAEDLKEHFKKAGEPPSVRLLTDKKTGKSKGCAFVEFDNQK-ALQKALKLHHTSLGGRKINV 73

RNA recognition motif 1 (RRM1) found in (U)-binding-splicing factor PUF60 and similar proteins; This subfamily corresponds to the RRM1 of PUF60, also termed FUSE-binding protein-interacting repressor (FBP-interacting repressor or FIR), or Ro-binding protein 1 (RoBP1), or Siah-binding protein 1 (Siah-BP1). PUF60 is an essential splicing factor that functions as a poly-U RNA-binding protein required to reconstitute splicing in depleted nuclear extracts. Its function is enhanced through interaction with U2 auxiliary factor U2AF65. PUF60 also controls human c-myc gene expression by binding and inhibiting the transcription factor far upstream sequence element (FUSE)-binding-protein (FBP), an activator of c-myc promoters. PUF60 contains two central RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal U2AF (U2 auxiliary factor) homology motifs (UHM) that harbors another RRM and binds to tryptophan-containing linear peptide motifs (UHM ligand motifs, ULMs) in several nuclear proteins. Research indicates that PUF60 binds FUSE as a dimer, and only the first two RRM domains participate in the single-stranded DNA recognition.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12370   3 VYVGSIYFELGEDTIRQAFAPFGPIKSIDMSWDPVTMKHKGFAFVEYEVPEAAQLALEQMNGVMLGGRNIKV 74

RNA recognition motif (RRM) found in RNA-binding protein RBM8A, RBM8B nd similar proteins; This subfamily corresponds to the RRM of RBM8, also termed binder of OVCA1-1 (BOV-1), or RNA-binding protein Y14, which is one of the components of the exon-exon junction complex (EJC). It has two isoforms, RBM8A and RBM8B, both of which are identical except that RBM8B is 16 amino acids shorter at its N-terminus. RBM8, together with other EJC components (such as Magoh, Aly/REF, RNPS1, Srm160, and Upf3), plays critical roles in postsplicing processing, including nuclear export and cytoplasmic localization of the mRNA, and the nonsense-mediated mRNA decay (NMD) surveillance process. RBM8 binds to mRNA 20-24 nucleotides upstream of a spliced exon-exon junction. It is also involved in spliced mRNA nuclear export, and the process of nonsense-mediated decay of mRNAs with premature stop codons. RBM8 forms a specific heterodimer complex with the EJC protein Magoh which then associates with Aly/REF, RNPS1, DEK, and SRm160 on the spliced mRNA, and inhibits ATP turnover by eIF4AIII, thereby trapping the EJC core onto RNA. RBM8 contains an N-terminal putative bipartite nuclear localization signal, one RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), in the central region, and a C-terminal serine-arginine rich region (SR domain) and glycine-arginine rich region (RG domain).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17137710  15 MRSV-----FVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12324   1 QRSVegwiiFVTGVHEEAQEEDIHDKFAEFGEIKNLHLNLDRRTGFVKGYALVEYETKKEAQAAIEGLNGKELLGQTISV 80

                ...
gi 17137710  90 DNA 92
Cdd:cd12324  81 DWA 83

RNA recognition motif (RRM) found in Saccharomyces cerevisiae U1 small nuclear ribonucleoprotein SNP1 and similar proteins; SNP1, also called U1 snRNP protein SNP1, or U1 small nuclear ribonucleoprotein 70 kDa homolog, or U1 70K, or U1 snRNP 70 kDa homolog, interacts with mRNA and is involved in nuclear mRNA splicing. It is a component of the spliceosome, where it is associated with snRNP U1 by binding stem loop I of U1 snRNA. Members in this family contain an N-terminal U1snRNP70 domain and an RNA recognition motif (RRM), also called RBD (RNA binding domain) or RNP (ribonucleoprotein domain).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17137710  16 RSVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNG---YEIGGRTLRVDna 92
Cdd:cd21615  19 KTLFVGRLDYSLTELELQKKFSKFGEIEKIRIVRDKETGKSRGYAFIVFKSESDAKNAFKEGNGlrgLKINDRTCIVD-- 96

                ....*.
gi 17137710  93 cTEKSR 98
Cdd:cd21615  97 -IERGR 101

RNA recognition motif 3 (RRM3) found in RNA-binding protein 19 (RBM19) and RNA recognition motif 2 found in multiple RNA-binding domain-containing protein 1 (MRD1); This subfamily corresponds to the RRM3 of RBM19 and RRM2 of MRD1. RBM19, also termed RNA-binding domain-1 (RBD-1), is a nucleolar protein conserved in eukaryotes involved in ribosome biogenesis by processing rRNA and is essential for preimplantation development. It has a unique domain organization containing 6 conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). MRD1 is encoded by a novel yeast gene MRD1 (multiple RNA-binding domain). It is well conserved in yeast and its homologs exist in all eukaryotes. MRD1 is present in the nucleolus and the nucleoplasm. It interacts with the 35 S precursor rRNA (pre-rRNA) and U3 small nucleolar RNAs (snoRNAs). It is essential for the initial processing at the A0-A2 cleavage sites in the 35 S pre-rRNA. MRD1 contains 5 conserved RRMs, which may play an important structural role in organizing specific rRNA processing events.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12316   2 LFVRNLPFTATEDELRELFEAFGKISEVHIPLDKQTKRSKGFAFVLFVIPEDAVKAYQELDGSIFQGRLLHV 73

RNA recognition motif (RRM) found in transformer-2 protein homolog TRA2-alpha, TRA2-beta and similar proteins; This subfamily corresponds to the RRM of two mammalian homologs of Drosophila transformer-2 (Tra2), TRA2-alpha, TRA2-beta (also termed SFRS10), and similar proteins found in eukaryotes. TRA2-alpha is a 40-kDa serine/arginine-rich (SR) protein that specifically binds to gonadotropin-releasing hormone (GnRH) exonic splicing enhancer on exon 4 (ESE4) and is necessary for enhanced GnRH pre-mRNA splicing. It strongly stimulates GnRH intron A excision in a dose-dependent manner. In addition, TRA2-alpha can interact with either 9G8 or SRp30c, which may also be crucial for ESE-dependent GnRH pre-mRNA splicing. TRA2-beta is a serine/arginine-rich (SR) protein that controls the pre-mRNA alternative splicing of the calcitonin/calcitonin gene-related peptide (CGRP), the survival motor neuron 1 (SMN1) protein and the tau protein. Both, TRA2-alpha and TRA2-beta, contains a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), flanked by the N- and C-terminal arginine/serine (RS)-rich regions.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 17137710  28 TEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRVDNACT 94
Cdd:cd12363  14 TERDLREVFSRYGPIEKVQVVYDQQTGRSRGFGFVYFESVEDAKEAKERLNGQEIDGRRIRVDYSIT 80

RNA recognition motif 3 (RRM3) found in CELF/Bruno-like family of RNA binding proteins CELF1, CELF2, CELF3, CELF4, CELF5, CELF6 and similar proteins; This subgroup corresponds to the RRM3 of the CUGBP1 and ETR-3-like factors (CELF) or BRUNOL (Bruno-like) proteins, a family of structurally related RNA-binding proteins involved in the regulation of pre-mRNA splicing in the nucleus and in the control of mRNA translation and deadenylation in the cytoplasm. The family contains six members: CELF-1 (also termed BRUNOL-2, or CUG-BP1, or NAPOR, or EDEN-BP), CELF-2 (also termed BRUNOL-3, or ETR-3, or CUG-BP2, or NAPOR-2), CELF-3 (also termed BRUNOL-1, or TNRC4, or ETR-1, or CAGH4, or ER DA4), CELF-4 (also termed BRUNOL-4), CELF-5 (also termed BRUNOL-5), CELF-6 (also termed BRUNOL-6). They all contain three highly conserved RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C-terminus of the protein. The low sequence conservation of the linker region is highly suggestive of a large variety in the co-factors that associate with the various CELF family members. Based on both sequence similarity and function, the CELF family can be divided into two subfamilies, the first containing CELFs 1 and 2, and the second containing CELFs 3, 4, 5, and 6. The different CELF proteins may act through different sites on at least some substrates. Furthermore, CELF proteins may interact with each other in varying combinations to influence alternative splicing in different contexts.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12362   1 LFVYHLPNEFTDQDLYQLFAPFGNVVSAKVFVDKNTGRSKGFGFVSYDNPLSAQAAIKAMNGFQVGGKRLKV 72

RNA recognition motif (RRM) found in eukaryotic translation initiation factor 4B (eIF-4B) and similar proteins; This subfamily corresponds to the RRM of eIF-4B, a multi-domain RNA-binding protein that has been primarily implicated in promoting the binding of 40S ribosomal subunits to mRNA during translation initiation. It contains two RNA-binding domains; the N-terminal well-conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), binds the 18S rRNA of the 40S ribosomal subunit and the C-terminal basic domain (BD), including two arginine-rich motifs (ARMs), binds mRNA during initiation, and is primarily responsible for the stimulation of the helicase activity of eIF-4A. eIF-4B also contains a DRYG domain (a region rich in Asp, Arg, Tyr, and Gly amino acids) in the middle, which is responsible for both, self-association of eIF-4B and binding to the p170 subunit of eIF3. Additional research indicates that eIF-4B can interact with the poly(A) binding protein (PABP) in mammalian cells, which can stimulate both, the eIF-4B-mediated activation of the helicase activity of eIF-4A and binding of poly(A) by PABP. eIF-4B has also been shown to interact specifically with the internal ribosome entry sites (IRES) of several picornaviruses which facilitate cap-independent translation initiation.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 17137710  19 FVGNIPYEATEEKLKEIFSEVGpVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMrNLNGYEIGGRTLRVDNA 92
Cdd:cd12402   6 YLGNLPYDVTEDDIEDFFRGLN-ISSVRLPRENGPGRLRGFGYVEFEDRESLIQAL-SLNEESLKNRRIRVDVA 77

RNA recognition motif 2 (RRM2) found in yeast multiple RNA-binding domain-containing protein 1 (MRD1) and similar proteins; This subgroup corresponds to the RRM2 of MRD1 which is encoded by a novel yeast gene MRD1 (multiple RNA-binding domain). It is well-conserved in yeast and its homologs exist in all eukaryotes. MRD1 is present in the nucleolus and the nucleoplasm. It interacts with the 35 S precursor rRNA (pre-rRNA) and U3 small nucleolar RNAs (snoRNAs). It is essential for the initial processing at the A0-A2 cleavage sites in the 35 S pre-rRNA. MRD1 contains 5 conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), which may play an important structural role in organizing specific rRNA processing events.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12566   5 LFLRNLPYSTKEDDLQKLFSKFGEVSEVHVPIDKKTKKSKGFAYVLFLDPEDAVQAYNELDGKVFQGRLIHI 76

RNA recognition motif (RRM) found in the Aly/REF family; This subfamily corresponds to the RRM of Aly/REF family which includes THO complex subunit 4 (THOC4, also termed Aly/REF), S6K1 Aly/REF-like target (SKAR, also termed PDIP3 or PDIP46) and similar proteins. THOC4 is an mRNA transporter protein with a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). It is involved in RNA transportation from the nucleus, and was initially identified as a transcription coactivator of LEF-1 and AML-1 for the TCRalpha enhancer function. In addition, THOC4 specifically binds to rhesus (RH) promoter in erythroid, and might be a novel transcription cofactor for erythroid-specific genes. SKAR shows high sequence homology with THOC4 and possesses one RRM as well. SKAR is widely expressed and localizes to the nucleus. It may be a critical player in the function of S6K1 in cell and organism growth control by binding the activated, hyperphosphorylated form of S6K1 but not S6K2. Furthermore, SKAR functions as a protein partner of the p50 subunit of DNA polymerase delta. In addition, SKAR may have particular importance in pancreatic beta cell size determination and insulin secretion.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDReSGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12418   3 VRVSNLHPDVTEEDLRELFGRVGPVKSVKINYDR-SGRSTGTAYVVFERPEDAEKAIKQFDGVLLDGQPMKV 73

U2 snRNP auxilliary factor, large subunit, splicing factor; These splicing factors consist of an N-terminal arginine-rich low complexity domain followed by three tandem RNA recognition motifs (pfam00076). The well-characterized members of this family are auxilliary components of the U2 small nuclear ribonuclearprotein splicing factor (U2AF). These proteins are closely related to the CC1-like subfamily of splicing factors (TIGR01622). Members of this subfamily are found in plants, metazoa and fungi.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 17137710    18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRVDNAC 93
Cdd:TIGR01642 298 IYIGNLPLYLGEDQIKELLESFGDLKAFNLIKDIATGLSKGYAFCEYKDPSVTDVAIAALNGKDTGDNKLHVQRAC 373

RNA recognition motif 1 (RRM1) found in splicing factor 3B subunit 4 (SF3B4) and similar proteins; This subfamily corresponds to the RRM1 of SF3B4, also termed pre-mRNA-splicing factor SF3b 49 kDa (SF3b50), or spliceosome-associated protein 49 (SAP 49). SF3B4 a component of the multiprotein complex splicing factor 3b (SF3B), an integral part of the U2 small nuclear ribonucleoprotein (snRNP) and the U11/U12 di-snRNP. SF3B is essential for the accurate excision of introns from pre-messenger RNA, and is involved in the recognition of the pre-mRNA's branch site within the major and minor spliceosomes. SF3B4 functions to tether U2 snRNP with pre-mRNA at the branch site during spliceosome assembly. It is an evolutionarily highly conserved protein with orthologs across diverse species. SF3B4 contains two closely adjacent N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). It binds directly to pre-mRNA and also interacts directly and highly specifically with another SF3B subunit called SAP 145.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12334   1 VYVGNLDEKVTEELLWELFIQAGPVVNVHMPKDRVTQQHQGYGFVEFLSEEDADYAIKIMNMIKLYGKPIRV 72

RNA recognition motif (RRM) found in heterogeneous nuclear ribonucleoprotein G (hnRNP G), Y chromosome RNA recognition motif 1 (hRBMY), testis-specific heterogeneous nuclear ribonucleoprotein G-T (hnRNP G-T) and similar proteins; This subfamily corresponds to the RRM domain of hnRNP G, also termed glycoprotein p43 or RBMX, an RNA-binding motif protein located on the X chromosome. It is expressed ubiquitously and has been implicated in the splicing control of several pre-mRNAs. Moreover, hnRNP G may function as a regulator of transcription for SREBP-1c and GnRH1. Research has shown that hnRNP G may also act as a tumor-suppressor since it upregulates the Txnip gene and promotes the fidelity of DNA end-joining activity. In addition, hnRNP G appears to play a critical role in proper neural development of zebrafish and frog embryos. The family also includes several paralogs of hnRNP G, such as hRBMY and hnRNP G-T (also termed RNA-binding motif protein, X-linked-like-2). Both, hRBMY and hnRNP G-T, are exclusively expressed in testis and critical for male fertility. Like hnRNP G, hRBMY and hnRNP G-T interact with factors implicated in the regulation of pre-mRNA splicing, such as hTra2-beta1 and T-STAR. Although members in this family share a high conserved N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), they appear to recognize different RNA targets. For instance, hRBMY interacts specifically with a stem-loop structure in which the loop is formed by the sequence CA/UCAA. In contrast, hnRNP G associates with single stranded RNA sequences containing a CCA/C motif. In addition to the RRM, hnRNP G contains a nascent transcripts targeting domain (NTD) in the middle region and a novel auxiliary RNA-binding domain (RBD) in its C-terminal region. The C-terminal RBD exhibits distinct RNA binding specificity, and would play a critical role in the regulation of alternative splicing by hnRNP G.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRVDNA 92
Cdd:cd12382   4 LFIGGLNTETNEKALEAVFGKYGRIVEVLLMKDRETNKSRGFAFVTFESPADAKDAARDMNGKELDGKAIKVEQA 78

RNA recognition motif 2 (RRM2) found in yeast nuclear polyadenylated RNA-binding protein 4 (Hrp1p or Nab4p) and similar proteins; This subfamily corresponds to the RRM1 of Hrp1p and similar proteins. Hrp1p or Nab4p, also termed cleavage factor IB (CFIB), is a sequence-specific trans-acting factor that is essential for mRNA 3'-end formation in yeast Saccharomyces cerevisiae. It can be UV cross-linked to RNA and specifically recognizes the (UA)6 RNA element required for both, the cleavage and poly(A) addition steps. Moreover, Hrp1p can shuttle between the nucleus and the cytoplasm, and play an additional role in the export of mRNAs to the cytoplasm. Hrp1p also interacts with Rna15p and Rna14p, two components of CF1A. In addition, Hrp1p functions as a factor directly involved in modulating the activity of the nonsense-mediated mRNA decay (NMD) pathway; it binds specifically to a downstream sequence element (DSE)-containing RNA and interacts with Upf1p, a component of the surveillance complex, further triggering the NMD pathway. Hrp1p contains two central RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an arginine-glycine-rich region harboring repeats of the sequence RGGF/Y.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNlNGYEIGGRTLRVDNA 92
Cdd:cd12330   2 IFVGGLAPDVTEEEFKEYFEQFGTVVDAVVMLDHDTGRSRGFGFVTFDSESAVEKVLSK-GFHELGGKKVEVKRA 75

RNA recognition motif 3 (RRM3) found in heterogeneous nuclear ribonucleoprotein R (hnRNP R) and similar proteins; This subfamily corresponds to the RRM3 in hnRNP R, hnRNP Q, and APOBEC-1 complementation factor (ACF). hnRNP R is a ubiquitously expressed nuclear RNA-binding protein that specifically bind mRNAs with a preference for poly(U) stretches and has been implicated in mRNA processing and mRNA transport, and also acts as a regulator to modify binding to ribosomes and RNA translation. hnRNP Q is also a ubiquitously expressed nuclear RNA-binding protein. It has been identified as a component of the spliceosome complex, as well as a component of the apobec-1 editosome, and has been implicated in the regulation of specific mRNA transport. ACF is an RNA-binding subunit of a core complex that interacts with apoB mRNA to facilitate C to U RNA editing. It may also act as an apoB mRNA recognition factor and chaperone and play a key role in cell growth and differentiation. This family also includes two functionally unknown RNA-binding proteins, RBM46 and RBM47. All members contain three conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 17137710  16 RSVFVGNIPYEATEEKLKEIFSEVGPVLSLKlvfdresgKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12251   2 KVLYVRNLMLSTTEEKLRELFSEYGKVERVK--------KIKDYAFVHFEERDDAVKAMEEMNGKELEGSEIEV 67

RNA recognition motif 1 (RRM1) found in the Hu proteins family, Drosophila sex-lethal (SXL), and similar proteins; This subfamily corresponds to the RRM1 of Hu proteins and SXL. The Hu proteins family represents a group of RNA-binding proteins involved in diverse biological processes. Since the Hu proteins share high homology with the Drosophila embryonic lethal abnormal vision (ELAV) protein, the Hu family is sometimes referred to as the ELAV family. Drosophila ELAV is exclusively expressed in neurons and is required for the correct differentiation and survival of neurons in flies. The neuronal members of the Hu family include Hu-antigen B (HuB or ELAV-2 or Hel-N1), Hu-antigen C (HuC or ELAV-3 or PLE21), and Hu-antigen D (HuD or ELAV-4), which play important roles in neuronal differentiation, plasticity and memory. HuB is also expressed in gonads. Hu-antigen R (HuR or ELAV-1 or HuA) is ubiquitously expressed Hu family member. It has a variety of biological functions mostly related to the regulation of cellular response to DNA damage and other types of stress. Hu proteins perform their cytoplasmic and nuclear molecular functions by coordinately regulating functionally related mRNAs. In the cytoplasm, Hu proteins recognize and bind to AU-rich RNA elements (AREs) in the 3' untranslated regions (UTRs) of certain target mRNAs, such as GAP-43, vascular epithelial growth factor (VEGF), the glucose transporter GLUT1, eotaxin and c-fos, and stabilize those ARE-containing mRNAs. They also bind and regulate the translation of some target mRNAs, such as neurofilament M, GLUT1, and p27. In the nucleus, Hu proteins function as regulators of polyadenylation and alternative splicing. Each Hu protein contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). RRM1 and RRM2 may cooperate in binding to an ARE. RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions. This family also includes the sex-lethal protein (SXL) from Drosophila melanogaster. SXL governs sexual differentiation and X chromosome dosage compensation in flies. It induces female-specific alternative splicing of the transformer (tra) pre-mRNA by binding to the tra uridine-rich polypyrimidine tract at the non-sex-specific 3' splice site during the sex-determination process. SXL binds to its own pre-mRNA and promotes female-specific alternative splicing. It contains an N-terminal Gly/Asn-rich domain that may be responsible for the protein-protein interaction, and tandem RRMs that show high preference to bind single-stranded, uridine-rich target RNA transcripts.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17137710  20 VGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12375   4 VNYLPQSMTQEELRSLFGAIGPIESCKLVRDKITGQSLGYGFVNYRDPNDARKAINTLNGLDLENKRLKV 73

RNA recognition motif (RRM) found in nuclear cap-binding protein subunit 2 (CBP20) and similar proteins; This subfamily corresponds to the RRM of CBP20, also termed nuclear cap-binding protein subunit 2 (NCBP2), or cell proliferation-inducing gene 55 protein, or NCBP-interacting protein 1 (NIP1). CBP20 is the small subunit of the nuclear cap binding complex (CBC), which is a conserved eukaryotic heterodimeric protein complex binding to 5'-capped polymerase II transcripts and plays a central role in the maturation of pre-mRNA and uracil-rich small nuclear RNA (U snRNA). CBP20 is most likely responsible for the binding of capped RNA. It contains an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and interacts with the second and third domains of CBP80, the large subunit of CBC.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRVD 90
Cdd:cd12240   1 LYVGNLSFYTTEEQIYELFSKCGDIKRIIMGLDKFKKTPCGFCFVEYYSREDAENAVKYLNGTKLDDRIIRVD 73

RNA recognition motif 3 (RRM3) found in RNA-binding protein 19 (RBM19) and similar proteins; This subgroup corresponds to the RRM3 of RBM19, also termed RNA-binding domain-1 (RBD-1), which is a nucleolar protein conserved in eukaryotes. It is involved in ribosome biogenesis by processing rRNA. In addition, it is essential for preimplantation development. RBM19 has a unique domain organization containing 6 conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17137710  18 VFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDRESGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12567   5 LFVRNLPYTCTEEDLEKLFSKYGPLSEVHFPIDSLTKKPKGFAFVTYMIPEHAVKAYAELDGTVFQGRLLHL 76

RNA recognition motif (RRM) found in vertebrate RNA-binding protein 7 (RBM7); This subfamily corresponds to the RRM of RBM7, a ubiquitously expressed pre-mRNA splicing factor that enhances messenger RNA (mRNA) splicing in a cell-specific manner or in a certain developmental process, such as spermatogenesis. RBM7 interacts with splicing factors SAP145 (the spliceosomal splicing factor 3b subunit 2) and SRp20. It may play a more specific role in meiosis entry and progression. Together with additional testis-specific RNA-binding proteins, RBM7 may regulate the splicing of specific pre-mRNA species that are important in the meiotic cell cycle. RBM7 contains an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a region lacking known homology at the C-terminus.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 17137710  16 RSVFVGNIPYEATEEKLKEIFSEVGPVLSLKLVFDREsGKPKGFGFCEYKDQETALSAMRNLNGYEIGGRTLRV 89
Cdd:cd12592   2 RTLFVGNLDTKVTEELLFELFLQAGPVIKVKIPKDKD-GKPKQFAFVNFKHEVSVPYAMNLLNGIKLYGRPLKI 74

RNA recognition motif 2 (RRM2) found in tRNA selenocysteine-associated protein 1 (SECp43) and similar proteins; This subfamily corresponds to the RRM2 in tRNA selenocysteine-associated protein 1 (SECp43), yeast negative growth regulatory protein NGR1 (RBP1), yeast protein NAM8, and similar proteins. SECp43 is an RNA-binding protein associated specifically with eukaryotic selenocysteine tRNA [tRNA(Sec)]. It may play an adaptor role in the mechanism of selenocysteine insertion. SECp43 is located primarily in the nucleus and contains two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal polar/acidic region. Yeast proteins, NGR1 and NAM8, show high sequence similarity with SECp43. NGR1 is a putative glucose-repressible protein that binds both RNA and single-stranded DNA (ssDNA). It may function in regulating cell growth in early log phase, possibly through its participation in RNA metabolism. NGR1 contains three RRMs, two of which are followed by a glutamine-rich stretch that may be involved in transcriptional activity. In addition, NGR1 has an asparagine-rich region near the C-terminus which also harbors a methionine-rich region. NAM8 is a putative RNA-binding protein that acts as a suppressor of mitochondrial splicing deficiencies when overexpressed in yeast. It may be a non-essential component of the mitochondrial splicing machinery. NAM8 also contains three RRMs.