RNA recognition motif 1 (RRM1) found in heterogeneous nuclear ribonucleoprotein M (hnRNP M) and similar proteins; This subfamily corresponds to the RRM1 of heterogeneous nuclear ribonucleoprotein M (hnRNP M), myelin expression factor 2 (MEF-2 or MyEF-2 or MST156) and similar proteins. hnRNP M is pre-mRNA binding protein that may play an important role in the pre-mRNA processing. It also preferentially binds to poly(G) and poly(U) RNA homopolymers. Moreover, hnRNP M is able to interact with early spliceosomes, further influencing splicing patterns of specific pre-mRNAs. hnRNP M functions as the receptor of carcinoembryonic antigen (CEA) that contains the penta-peptide sequence PELPK signaling motif. In addition, hnRNP M and another splicing factor Nova-1 work together as dopamine D2 receptor (D2R) pre-mRNA-binding proteins. They regulate alternative splicing of D2R pre-mRNA in an antagonistic manner. hnRNP M contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an unusual hexapeptide-repeat region rich in methionine and arginine residues (MR repeat motif). MEF-2 is a sequence-specific single-stranded DNA (ssDNA) binding protein that binds specifically to ssDNA derived from the proximal (MB1) element of the myelin basic protein (MBP) promoter and represses transcription of the MBP gene. MEF-2 shows high sequence homology with hnRNP M. It also contains three RRMs, which may be responsible for its ssDNA binding activity.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 386765401  58 RVYISNIPYDYRWQDLKDLFRRIVGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVKED 133
Cdd:cd12385    1 RVFISNIPYDYKWQDLKDLFREKVGEVTYVELFKDENGKSRGCGIVEFKDLESVQKALETMNRYELKGRKLVVKED 76

RNA recognition motif 1 (RRM1) found in heterogeneous nuclear ribonucleoprotein M (hnRNP M) and similar proteins; This subfamily corresponds to the RRM1 of heterogeneous nuclear ribonucleoprotein M (hnRNP M), myelin expression factor 2 (MEF-2 or MyEF-2 or MST156) and similar proteins. hnRNP M is pre-mRNA binding protein that may play an important role in the pre-mRNA processing. It also preferentially binds to poly(G) and poly(U) RNA homopolymers. Moreover, hnRNP M is able to interact with early spliceosomes, further influencing splicing patterns of specific pre-mRNAs. hnRNP M functions as the receptor of carcinoembryonic antigen (CEA) that contains the penta-peptide sequence PELPK signaling motif. In addition, hnRNP M and another splicing factor Nova-1 work together as dopamine D2 receptor (D2R) pre-mRNA-binding proteins. They regulate alternative splicing of D2R pre-mRNA in an antagonistic manner. hnRNP M contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an unusual hexapeptide-repeat region rich in methionine and arginine residues (MR repeat motif). MEF-2 is a sequence-specific single-stranded DNA (ssDNA) binding protein that binds specifically to ssDNA derived from the proximal (MB1) element of the myelin basic protein (MBP) promoter and represses transcription of the MBP gene. MEF-2 shows high sequence homology with hnRNP M. It also contains three RRMs, which may be responsible for its ssDNA binding activity.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 386765401  58 RVYISNIPYDYRWQDLKDLFRRIVGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVKED 133
Cdd:cd12385    1 RVFISNIPYDYKWQDLKDLFREKVGEVTYVELFKDENGKSRGCGIVEFKDLESVQKALETMNRYELKGRKLVVKED 76

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 386765401    58 RVYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFD-ESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV 130
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSKF-GKVESVRLVRDkETGKSKGFAFVEFESEEDAEKALEALNGKELDGRPLKV 73

polyadenylate binding protein, human types 1, 2, 3, 4 family; These eukaryotic proteins recognize the poly-A of mRNA and consists of four tandem RNA recognition domains at the N-terminus (rrm: pfam00076) followed by a PABP-specific domain (pfam00658) at the C-terminus. The protein is involved in the transport of mRNA's from the nucleus to the cytoplasm. There are four paralogs in Homo sapiens which are expressed in testis, platelets, broadly expressed and of unknown tissue range.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 386765401   59 VYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV-----KED 133
Cdd:TIGR01628 288 LYVKNLDDTVTDEKLRELFSEC-GEITSAKVMLDEKGVSRGFGFVCFSNPEEANRAVTEMHGRMLGGKPLYValaqrKEQ 366

                          90
                  ....*....|...
gi 386765401  134 HGEQ-RDQYGRIV 145
Cdd:TIGR01628 367 RRAHlQDQFMQLQ 379

RNA recognition motif 1 (RRM1) found in heterogeneous nuclear ribonucleoprotein M (hnRNP M) and similar proteins; This subfamily corresponds to the RRM1 of heterogeneous nuclear ribonucleoprotein M (hnRNP M), myelin expression factor 2 (MEF-2 or MyEF-2 or MST156) and similar proteins. hnRNP M is pre-mRNA binding protein that may play an important role in the pre-mRNA processing. It also preferentially binds to poly(G) and poly(U) RNA homopolymers. Moreover, hnRNP M is able to interact with early spliceosomes, further influencing splicing patterns of specific pre-mRNAs. hnRNP M functions as the receptor of carcinoembryonic antigen (CEA) that contains the penta-peptide sequence PELPK signaling motif. In addition, hnRNP M and another splicing factor Nova-1 work together as dopamine D2 receptor (D2R) pre-mRNA-binding proteins. They regulate alternative splicing of D2R pre-mRNA in an antagonistic manner. hnRNP M contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an unusual hexapeptide-repeat region rich in methionine and arginine residues (MR repeat motif). MEF-2 is a sequence-specific single-stranded DNA (ssDNA) binding protein that binds specifically to ssDNA derived from the proximal (MB1) element of the myelin basic protein (MBP) promoter and represses transcription of the MBP gene. MEF-2 shows high sequence homology with hnRNP M. It also contains three RRMs, which may be responsible for its ssDNA binding activity.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 386765401  58 RVYISNIPYDYRWQDLKDLFRRIVGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVKED 133
Cdd:cd12385    1 RVFISNIPYDYKWQDLKDLFREKVGEVTYVELFKDENGKSRGCGIVEFKDLESVQKALETMNRYELKGRKLVVKED 76

RNA recognition motif 1 (RRM1) found in vertebrate heterogeneous nuclear ribonucleoprotein M (hnRNP M); This subgroup corresponds to the RRM1 of hnRNP M, a pre-mRNA binding protein that may play an important role in the pre-mRNA processing. It also preferentially binds to poly(G) and poly(U) RNA homopolymers. Moreover, hnRNP M is able to interact with early spliceosomes, further influencing splicing patterns of specific pre-mRNAs. hnRNP M functions as the receptor of carcinoembryonic antigen (CEA) that contains the penta-peptide sequence PELPK signaling motif. In addition, hnRNP M and another splicing factor Nova-1 work together as dopamine D2 receptor (D2R) pre-mRNA-binding proteins. They regulate alternative splicing of D2R pre-mRNA in an antagonistic manner. hnRNP M contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an unusual hexapeptide-repeat region rich in methionine and arginine residues (MR repeat motif).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 386765401  58 RVYISNIPYDYRWQDLKDLFRRIVGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVKED 133
Cdd:cd12657    1 RVFISNIPFDVKWQTLKDLVKEKVGEVTYVELLMDAEGKSRGCAVVEFKTEESMKKAVEVLNKHSFNGRPLKVKED 76

RNA recognition motif (RRM) superfamily; RRM, also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), is a highly abundant domain in eukaryotes found in proteins involved in post-transcriptional gene expression processes including mRNA and rRNA processing, RNA export, and RNA stability. This domain is 90 amino acids in length and consists of a four-stranded beta-sheet packed against two alpha-helices. RRM usually interacts with ssRNA, but is also known to interact with ssDNA as well as proteins. RRM binds a variable number of nucleotides, ranging from two to eight. The active site includes three aromatic side-chains located within the conserved RNP1 and RNP2 motifs of the domain. The RRM domain is found in a variety heterogeneous nuclear ribonucleoproteins (hnRNPs), proteins implicated in regulation of alternative splicing, and protein components of small nuclear ribonucleoproteins (snRNPs).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 386765401  59 VYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVK 131
Cdd:cd00590    1 LFVGNLPPDTTEEDLRELFSK-FGEVVSVRIVRDRDGKSKGFAFVEFESPEDAEKALEALNGTELGGRPLKVS 72

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

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 386765401  58 RVYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFD-ESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVKE 132
Cdd:COG0724    3 KIYVGNLPYSVTEEDLRELFSEY-GEVTSVKLITDrETGRSRGFGFVEMPDDEEAQAAIEALNGAELMGRTLKVNE 77

RNA recognition motif (RRM) found in cleavage stimulation factor subunit 2 (CSTF2), yeast ortholog mRNA 3'-end-processing protein RNA15 and similar proteins; This subfamily 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. The family also includes yeast ortholog mRNA 3'-end-processing protein RNA15 and similar proteins. RNA15 is a core subunit of cleavage factor IA (CFIA), an essential transcriptional 3'-end processing factor from Saccharomyces cerevisiae. RNA recognition by CFIA is mediated by an N-terminal RRM, which is contained in the RNA15 subunit of the complex. The RRM of RNA15 has a strong preference for GU-rich RNAs, mediated by a binding pocket that is entirely conserved in both yeast and vertebrate RNA15 orthologs.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 386765401  59 VYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFD-ESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV 130
Cdd:cd12398    3 VFVGNIPYDATEEQLKEIFSE-VGPVVSFRLVTDrETGKPKGYGFCEFRDAETALSAVRNLNGYELNGRPLRV 74

RNA recognition motif 2 (RRM2) found in Saccharomyces cerevisiae protein HRB1, G-strand-binding protein 2 (GBP2) and similar proteins; The family includes Saccharomyces cerevisiae protein HRB1 (also called protein TOM34) and GBP2, both of which are SR-like mRNA-binding proteins which shuttle from the nucleus to the cytoplasm when bound to the mature mRNA molecules. They act as quality control factors for spliced mRNAs. GBP2, also called RAP1 localization factor 6, is a single-strand telomeric DNA-binding protein that binds single-stranded telomeric sequences of the type (TG[1-3])n in vitro. It also binds to RNA. GBP2 influences the localization of RAP1 in the nuclei and plays a role in modulating telomere length. Members in this family contain three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The model corresponds to the second RRM motif.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 386765401  59 VYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVK 131
Cdd:cd21606    4 VFIANLPYSINWQALKDMFKE-CGDVLRADVELDYNGRSRGFGTVIYATEEEMHRAIDTFNGYELEGRVLEVK 75

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 386765401  51 SRERRNCRVYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFD-ESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELV 129
Cdd:cd12671    1 ASDRSLRSVFVGNIPYEATEEQLKDIFSE-VGPVVSFRLVYDrETGKPKGYGFCEYQDQETALSAMRNLNGYELNGRALR 79

                 .
gi 386765401 130 V 130
Cdd:cd12671   80 V 80

RNA recognition motif 3 (RRM3) found in heterogeneous nuclear ribonucleoprotein M (hnRNP M) and similar proteins; This subfamily corresponds to the RRM3 of heterogeneous nuclear ribonucleoprotein M (hnRNP M), myelin expression factor 2 (MEF-2 or MyEF-2 or MST156) and similar proteins. hnRNP M is pre-mRNA binding protein that may play an important role in the pre-mRNA processing. It also preferentially binds to poly(G) and poly(U) RNA homopolymers. hnRNP M is able to interact with early spliceosomes, further influencing splicing patterns of specific pre-mRNAs. hnRNP M functions as the receptor of carcinoembryonic antigen (CEA) that contains the penta-peptide sequence PELPK signaling motif. In addition, hnRNP M and another splicing factor Nova-1 work together as dopamine D2 receptor (D2R) pre-mRNA-binding proteins. They regulate alternative splicing of D2R pre-mRNA in an antagonistic manner. hnRNP M contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an unusual hexapeptide-repeat region rich in methionine and arginine residues (MR repeat motif). MEF-2 is a sequence-specific single-stranded DNA (ssDNA) binding protein that binds specifically to ssDNA derived from the proximal (MB1) element of the myelin basic protein (MBP) promoter and represses transcription of the MBP gene. MEF-2 shows high sequence homology with hnRNP M. It also contains three RRMs, which may be responsible for its ssDNA binding activity.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 386765401  59 VYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFDEsGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVK 131
Cdd:cd12387    1 IFVRNLPFDYTWQKLKDKFKD-CGHVTFASIKMEN-GKSKGCGTVRFDSPEDAENACRMMNGSKQSGREIDVR 71

RNA recognition motif 3 (RRM3) found in vertebrate heterogeneous nuclear ribonucleoprotein M (hnRNP M); This subgroup corresponds to the RRM3 of hnRNP M, a pre-mRNA binding protein that may play an important role in the pre-mRNA processing. It also preferentially binds to poly(G) and poly(U) RNA homopolymers. Moreover, hnRNP M is able to interact with early spliceosomes, further influencing splicing patterns of specific pre-mRNAs. hnRNP M functions as the receptor of carcinoembryonic antigen (CEA) that contains the penta-peptide sequence PELPK signaling motif. In addition, hnRNP M and another splicing factor Nova-1 work together as dopamine D2 receptor (D2R) pre-mRNA-binding proteins. They regulate alternative splicing of D2R pre-mRNA in an antagonistic manner. hnRNP M contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an unusual hexapeptide-repeat region rich in methionine and arginine residues (MR repeat motif).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 386765401  58 RVYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFdESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVKED 133
Cdd:cd12661    1 QIFVRNLPFDFTWKMLKDKFNE-CGHVLYADIKM-ENGKSKGCGVVRFESPEVAERACRMMNGIKLNGREIDVRID 74

RNA recognition motif 2 (RRM2) found in RNA-binding protein 28 (RBM28) and similar proteins; This subfamily corresponds to the RRM2 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 386765401  58 RVYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV 130
Cdd:cd12414    1 RLIVRNLPFKCTEDDLKKLFSKF-GKVLEVTIPKKPDGKLRGFAFVQFTNVADAAKAIKGMNGKKIKGRPVAV 72

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 386765401  57 CRVYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVK 131
Cdd:cd12418    1 TRVRVSNLHPDVTEEDLRELFGRV-GPVKSVKINYDRSGRSTGTAYVVFERPEDAEKAIKQFDGVLLDGQPMKVE 74

RNA recognition motif (RRM) found in vertebrate RNA binding protein fox-1 homologs and similar proteins; This subfamily corresponds to the RRM of several tissue-specific alternative splicing isoforms of vertebrate RNA binding protein Fox-1 homologs, which show high sequence similarity to the Caenorhabditis elegans feminizing locus on X (Fox-1) gene encoding Fox-1 protein. RNA binding protein Fox-1 homolog 1 (RBFOX1), also termed ataxin-2-binding protein 1 (A2BP1), or Fox-1 homolog A, or hexaribonucleotide-binding protein 1 (HRNBP1), is predominantly expressed in neurons, skeletal muscle and heart. It regulates alternative splicing of tissue-specific exons by binding to UGCAUG elements. Moreover, RBFOX1 binds to the C-terminus of ataxin-2 and forms an ataxin-2/A2BP1 complex involved in RNA processing. RNA binding protein fox-1 homolog 2 (RBFOX2), also termed Fox-1 homolog B, or hexaribonucleotide-binding protein 2 (HRNBP2), or RNA-binding motif protein 9 (RBM9), or repressor of tamoxifen transcriptional activity, is expressed in ovary, whole embryo, and human embryonic cell lines in addition to neurons and muscle. RBFOX2 activates splicing of neuron-specific exons through binding to downstream UGCAUG elements. RBFOX2 also functions as a repressor of tamoxifen activation of the estrogen receptor. RNA binding protein Fox-1 homolog 3 (RBFOX3 or NeuN or HRNBP3), also termed Fox-1 homolog C, is a nuclear RNA-binding protein that regulates alternative splicing of the RBFOX2 pre-mRNA, producing a message encoding a dominant negative form of the RBFOX2 protein. Its message is detected exclusively in post-mitotic regions of embryonic brain. Like RBFOX1, both RBFOX2 and RBFOX3 bind to the hexanucleotide UGCAUG elements and modulate brain and muscle-specific splicing of exon EIIIB of fibronectin, exon N1 of c-src, and calcitonin/CGRP. Members in this family also harbor one RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 386765401  58 RVYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFDESGkARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV 130
Cdd:cd12407    2 RLHVSNIPFRFRDPDLRQMFGQ-FGTILDVEIIFNERG-SKGFGFVTFANSADADRAREKLNGTVVEGRKIEV 72

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 386765401  57 CRVYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFDE-SGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV 130
Cdd:cd12370    1 CRVYVGSIYFELGEDTIRQAFAPF-GPIKSIDMSWDPvTMKHKGFAFVEYEVPEAAQLALEQMNGVMLGGRNIKV 74

RNA recognition motif (RRM) found in pre-mRNA cleavage factor Im 68 kDa subunit (CFIm68 or CPSF6), pre-mRNA cleavage factor Im 59 kDa subunit (CFIm59 or CPSF7), and similar proteins; This subfamily corresponds to the RRM of cleavage factor Im (CFIm) subunits. Cleavage factor Im (CFIm) is a highly conserved component of the eukaryotic mRNA 3' processing machinery that functions in UGUA-mediated poly(A) site recognition, the regulation of alternative poly(A) site selection, mRNA export, and mRNA splicing. It is a complex composed of a small 25 kDa (CFIm25) subunit and a larger 59/68/72 kDa subunit. Two separate genes, CPSF6 and CPSF7, code for two isoforms of the large subunit, CFIm68 and CFIm59. Structurally related CFIm68 and CFIm59, also termed cleavage and polyadenylation specificity factor subunit 6 (CPSF7), or cleavage and polyadenylation specificity factor 59 kDa subunit (CPSF59), are functionally redundant. Both contains an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a central proline-rich region, and a C-terminal RS-like domain. Their N-terminal RRM mediates the interaction with CFIm25, and also serves to enhance RNA binding and facilitate RNA looping.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 386765401  59 VYISNIPYdyrW---QDLKDLFRRIvGSIEYVQLFFDE---SGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVK 131
Cdd:cd12372    1 LYVGNLQW---WttdEDLEGACASF-GVVDVKEIKFFEhkaNGKSKGYAYVEFASPAAAAAVKEKLEKREFNGRPCVVT 75

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 386765401  59 VYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFD-ESGKARGCGIVEFKDPENVQKALEKMNR------YEVNGRELVV 130
Cdd:cd12415    3 VFIRNLSFDTTEEDLKEFFSKF-GEVKYARIVLDkDTGHSKGTAFVQFKTKESADKCIEAANDesedggLVLDGRKLIV 80

RNA recognition motif 2 (RRM2) found in heterogeneous nuclear ribonucleoprotein M (hnRNP M) and similar proteins; This subfamily corresponds to the RRM2 of heterogeneous nuclear ribonucleoprotein M (hnRNP M), myelin expression factor 2 (MEF-2 or MyEF-2 or MST156) and similar proteins. hnRNP M is pre-mRNA binding protein that may play an important role in the pre-mRNA processing. It also preferentially binds to poly(G) and poly(U) RNA homopolymers. hnRNP M is able to interact with early spliceosomes, further influencing splicing patterns of specific pre-mRNAs. It functions as the receptor of carcinoembryonic antigen (CEA) that contains the penta-peptide sequence PELPK signaling motif. In addition, hnRNP M and another splicing factor Nova-1 work together as dopamine D2 receptor (D2R) pre-mRNA-binding proteins. They regulate alternative splicing of D2R pre-mRNA in an antagonistic manner. hnRNP M contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an unusual hexapeptide-repeat region rich in methionine and arginine residues (MR repeat motif). MEF-2 is a sequence-specific single-stranded DNA (ssDNA) binding protein that binds specifically to ssDNA derived from the proximal (MB1) element of the myelin basic protein (MBP) promoter and represses transcription of the MBP gene. MEF-2 shows high sequence homology with hnRNP M. It also contains three RRMs, which may be responsible for its ssDNA binding activity.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 386765401  59 VYISNIPYDYRWQDLKDLFRrIVGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVKED 133
Cdd:cd12386    1 IFVANLDYKVGWKKLKEVFK-LAGKVVRADIREDKDGKSRGMGVVQFEHPIEAVQAISMFNGQMLFDRPMRVKMD 74

RNA recognition motif 1 (RRM1) found in yeast regulator of rDNA transcription protein 5 (RRT5) and similar proteins; This subfamily corresponds to the RRM1 of the lineage specific family containing a group of uncharacterized yeast regulators of rDNA transcription protein 5 (RRT5), which may play roles in the modulation of rDNA transcription. RRT5 contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 386765401  58 RVYISNIPYDYRWQDLKDLFrrivGSIEYVQLF-------FDESGKARGCGI--VEFKDPENVQKALEKMNRYEVNGREL 128
Cdd:cd12409    1 RVYISNLSYSTTEEELEELL----KDYKPVSVLipsytvrGFRSRKHRPLGIayAEFSSVEEAEKVVKDLNGKVFKGRKL 76

                 ...
gi 386765401 129 VVK 131
Cdd:cd12409   77 FVK 79

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 386765401  59 VYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFD-ESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV 130
Cdd:cd12362    1 LFVYHLPNEFTDQDLYQLFAPF-GNVVSAKVFVDkNTGRSKGFGFVSYDNPLSAQAAIKAMNGFQVGGKRLKV 72

RNA recognition motif in type II polyadenylate-binding proteins; This subfamily corresponds to the RRM of type II polyadenylate-binding proteins (PABPs), including polyadenylate-binding protein 2 (PABP-2 or PABPN1), embryonic polyadenylate-binding protein 2 (ePABP-2 or PABPN1L) and similar proteins. PABPs are 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. ePABP-2 is predominantly located in the cytoplasm and PABP-2 is located in the nucleus. In contrast to the type I PABPs containing four copies of RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), the type II PABPs contains a single highly-conserved RRM. This subfamily also includes Saccharomyces cerevisiae RBP29 (SGN1, YIR001C) gene encoding cytoplasmic mRNA-binding protein Rbp29 that binds preferentially to poly(A). Although not essential for cell viability, Rbp29 plays a role in modulating the expression of cytoplasmic mRNA. Like other type II PABPs, Rbp29 contains one RRM only.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 386765401  59 VYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFDE-SGKARGCGIVEFKDPENVQKALeKMNRYEVNGRELVV 130
Cdd:cd12306    2 IYVGNVDYGTTPEELQAHFKS-CGTINRVTILCDKfTGQPKGFAYIEFVDKSSVENAL-LLNESEFRGRQIKV 72

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 386765401  59 VYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFD-ESGKARGCGIVEFKDPENVQKALeKMNRYEVNGRELVVK 131
Cdd:cd12395    2 VFVGNLPFDIEEEELRKHFEDC-GDVEAVRIVRDrETGIGKGFGYVLFKDKDSVDLAL-KLNGSKLRGRKLRVK 73

RNA recognition motif 2 (RRM2) found in serine/arginine-rich splicing factor 4 (SRSF4) and similar proteins; This subfamily corresponds to the RRM2 of three serine/arginine (SR) proteins: serine/arginine-rich splicing factor 4 (SRSF4 or SRp75 or SFRS4), serine/arginine-rich splicing factor 5 (SRSF5 or SRp40 or SFRS5 or HRS), serine/arginine-rich splicing factor 6 (SRSF6 or SRp55). SRSF4 plays an important role in both, constitutive and alternative, splicing of many pre-mRNAs. It can shuttle between the nucleus and cytoplasm. SRSF5 regulates both alternative splicing and basal splicing. It is the only SR protein efficiently selected from nuclear extracts (NE) by the splicing enhancer (ESE) and is essential for enhancer activation. SRSF6 preferentially interacts with a number of purine-rich splicing enhancers (ESEs) to activate splicing of the ESE-containing exon. It is the only protein from HeLa nuclear extract or purified SR proteins that specifically binds B element RNA after UV irradiation. SRSF6 may also recognize different types of RNA sites. Members in this family contain two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by a C-terminal RS domains rich in serine-arginine dipeptides.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 386765401  58 RVYISNIPYDYRWQDLKDLFRRiVGSIEYVqlffDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVKED 133
Cdd:cd12600    2 RLIVENLSSRVSWQDLKDYMRQ-AGEVTYA----DAHKQRKNEGVVEFASYSDMKNAIEKLDGTELNGRKIRLVED 72

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 386765401  58 RVYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFD-ESGKARGCGIVEFKDPENVQKALEKMNRYEVNGREL 128
Cdd:cd12316    1 RLFVRNLPFTATEDELRELFEAF-GKISEVHIPLDkQTKRSKGFAFVLFVIPEDAVKAYQELDGSIFQGRLL 71

RNA recognition motif 2 (RRM2) found in yeast nucleolar protein 13 (Nop13p) and similar proteins; This subfamily corresponds to the RRM2 of Nop13p encoded by YNL175c from Saccharomyces cerevisiae. It shares high sequence similarity with nucleolar protein 12 (Nop12p). Both Nop12p and Nop13p are not essential for growth. However, unlike Nop12p that is localized to the nucleolus, Nop13p localizes primarily to the nucleolus but is also present in the nucleoplasm to a lesser extent. Nop13p contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 386765401  59 VYISNIPYDYRWQDLKDLFRRiVGSIEYVQLF-FDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV 130
Cdd:cd12397    1 LFVGNLSFETTEEDLRKHFAP-AGKIRKVRMAtFEDSGKCKGFAFVDFKEIESATNAVKGPINHSLNGRDLRV 72

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 386765401  61 ISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFDE-SGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV 130
Cdd:cd12375    4 VNYLPQSMTQEELRSLFGAI-GPIESCKLVRDKiTGQSLGYGFVNYRDPNDARKAINTLNGLDLENKRLKV 73

RNA recognition motif 2 (RRM2) found in RNA-binding protein 40 (RBM40) and similar proteins; This subfamily corresponds to the RRM2 of RBM40 and the RRM of RBM41. RBM40, also known as RNA-binding region-containing protein 3 (RNPC3) or U11/U12 small nuclear ribonucleoprotein 65 kDa protein (U11/U12-65K protein). It serves as a bridging factor between the U11 and U12 snRNPs. It contains two RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), connected by a linker that includes a proline-rich region. It binds to the U11-associated 59K protein via its RRM1 and employs the RRM2 to bind hairpin III of the U12 small nuclear RNA (snRNA). The proline-rich region might be involved in protein-protein interactions. RBM41 contains only one RRM. Its biological function remains unclear.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 386765401  56 NCRVYISNIPYDYRWQDLKDLFRRIVGSIEYVQLFFD----ESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV 130
Cdd:cd12239    1 SNRLYVKNLSKRVSEKDLKYIFGRFVDSSSEEKNMFDirlmTEGRMKGQAFITFPSEELAEKALNLTNGYVLHGKPMVV 79

RNA recognition motif 1 (RRM1) found in vertebrate RNA-binding protein 39 (RBM39) and similar proteins; This subfamily corresponds to the RRM1 of RNA-binding protein 39 (RBM39), RNA-binding protein 23 (RBM23) and similar proteins. RBM39 (also termed HCC1) is a nuclear autoantigen that contains an N-terminal arginine/serine rich (RS) motif and three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). An octapeptide sequence called the RS-ERK motif is repeated six times in the RS region of RBM39. Although the cellular function of RBM23 remains unclear, it shows high sequence homology to RBM39 and contains two RRMs. It may possibly function as a pre-mRNA splicing factor.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 386765401  59 VYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFDE-SGKARGCGIVEFKDPENVQKALEkMNRYEVNGRELVVK 131
Cdd:cd12283    2 VFVMQLSLKARERDLYEFFSK-AGKVRDVRLIMDRnSRRSKGVAYVEFYDVESVPLALA-LTGQRLLGQPIMVQ 73

RNA recognition motif 1 (RRM1) found in Schizosaccharomyces pombe mRNA export factor Crp79 and similar proteins; Crp79, also called meiotic expression up-regulated protein 5 (Mug5), or polyadenylate-binding protein crp79, or PABP, or poly(A)-binding protein, is an auxiliary mRNA export factor that binds the poly(A) tail of mRNA and is involved in the export of mRNA from the nucleus to the cytoplasm. Members in this family contain three 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 386765401  59 VYISNIPYDYRWQDLKDLFRRIvGSIEYV---QLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVK 131
Cdd:cd21619    4 IYVGNIDMTINEDALEKIFSRY-GQVESVrrpPIHTDKADRTTGFGFIKYTDAESAERAMQQADGILLGRRRLVVR 78

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 386765401  59 VYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFDE-SGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVK 131
Cdd:cd12413    2 LFVRNLPYDTTDEQLEELFSD-VGPVKRCFVVKDKgKDKCRGFGYVTFALAEDAQRALEEVKGKKFGGRKIKVE 74

heterogeneous nuclear ribonucleoprotein R, Q family; Sequences in this subfamily include the human heterogeneous nuclear ribonucleoproteins (hnRNP) R, Q, and APOBEC-1 complementation factor (aka APOBEC-1 stimulating protein). These proteins contain three RNA recognition domains (rrm: pfam00076) and a somewhat variable C-terminal domain.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 386765401   55 RNCRVYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFDESGKARGCGIVEFKDPENVQKALEKMNRYEV-NGRELVV 130
Cdd:TIGR01648  57 RGCEVFVGKIPRDLYEDELVPLFEKA-GPIYELRLMMDFSGQNRGYAFVTFCGKEEAKEAVKLLNNYEIrPGRLLGV 132

RNA recognition motif (RRM) found in Zinc finger CCHC-type and RNA-binding motif-containing protein 1 (ZCRB1) and similar proteins; This subfamily corresponds to the RRM of ZCRB1, also termed MADP-1, or U11/U12 small nuclear ribonucleoprotein 31 kDa protein (U11/U12 snRNP 31 or U11/U12-31K), a novel multi-functional nuclear factor, which may be involved in morphine dependence, cold/heat stress, and hepatocarcinoma. It is located in the nucleoplasm, but outside the nucleolus. ZCRB1 is one of the components of U11/U12 snRNPs that bind to U12-type pre-mRNAs and form a di-snRNP complex, simultaneously recognizing the 5' splice site and branchpoint sequence. ZCRB1 is characterized by an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a CCHC-type Zinc finger motif. In addition, it contains core nucleocapsid motifs, and Lys- and Glu-rich domains.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 386765401  57 CRVYISNIPYDYRWQDLKDLFRRIvGSIEYVQLFFD-ESGKARGCGIVEFKDPENVQKALEKMNRYEVNGREL 128
Cdd:cd12393    2 STVYVSNLPFSLTNNDLHQIFSKY-GKVVKVTILKDkETRKSKGVAFVLFLDRESAHNAVRAMNNKELFGRTL 73

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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 386765401  58 RVYISNIPYDYRWQDLKDLFRRiVGSIEYVQLFFD-ESGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVVkeDHGE 136
Cdd:cd12449    2 KLFVGGLSFDTNEQSLEEVFSK-YGQISEVVVVKDrETQRSRGFGFVTFENPDDAKDAMMAMNGKSLDGRQIRV--DQAG 78

                 .
gi 386765401 137 Q 137
Cdd:cd12449   79 K 79

poly-U binding splicing factor, half-pint family; The proteins represented by this model contain three RNA recognition motifs (rrm: pfam00076) and have been characterized as poly-pyrimidine tract binding proteins associated with RNA splicing factors. In the case of PUF60 (GP|6176532), in complex with p54, and in the presence of U2AF, facilitates association of U2 snRNP with pre-mRNA.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 386765401   57 CRVYISNIPYDYRwqdlKDLFRRIV---GSIEYVQLFFDE-SGKARGCGIVEFKDPENVQKALEKMNRYEVNGRELVV 130
Cdd:TIGR01645 108 CRVYVGSISFELR----EDTIRRAFdpfGPIKSINMSWDPaTGKHKGFAFVEYEVPEAAQLALEQMNGQMLGGRNIKV 181