basic Helix-Loop-Helix-zipper (bHLHzip) domain found in protein Max and similar proteins; Max, also termed Class D basic helix-loop-helix protein 4 (bHLHd4), or Myc-associated factor X, is a bHLHZip transcription regulator that forms a sequence-specific DNA-binding protein complex with MYC or MAD which recognizes the core sequence 5'-CAC[GA]TG-3'. The MYC:MAX complex is a transcriptional activator, whereas the MAD:MAX complex is a transcriptional repressor. Max homodimer bind DNA but is transcriptionally inactive. Targeted deletion of max results in early embryonic lethality in mice.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILDKATEYIQYMRRKNHTHQQDIDDLKRQN 92
Cdd:cd11406     1 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILKKATEYIQYMRRKNHTHQQDIDDLKRQN 69

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in protein Max and similar proteins; Max, also termed Class D basic helix-loop-helix protein 4 (bHLHd4), or Myc-associated factor X, is a bHLHZip transcription regulator that forms a sequence-specific DNA-binding protein complex with MYC or MAD which recognizes the core sequence 5'-CAC[GA]TG-3'. The MYC:MAX complex is a transcriptional activator, whereas the MAD:MAX complex is a transcriptional repressor. Max homodimer bind DNA but is transcriptionally inactive. Targeted deletion of max results in early embryonic lethality in mice.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILDKATEYIQYMRRKNHTHQQDIDDLKRQN 92
Cdd:cd11406     1 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILKKATEYIQYMRRKNHTHQQDIDDLKRQN 69

helix loop helix domain;

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|...
gi 2244985492   29 NALERKRRDHIKDSFHSLRDSVPSL-QGEKASRAQILDKATEYIQYMRRKNHT 80
Cdd:smart00353   1 NARERRRRRKINEAFDELRSLLPTLpKNKKLSKAEILRLAIEYIKSLQEELQK 53

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in protein Max and similar proteins; Max, also termed Class D basic helix-loop-helix protein 4 (bHLHd4), or Myc-associated factor X, is a bHLHZip transcription regulator that forms a sequence-specific DNA-binding protein complex with MYC or MAD which recognizes the core sequence 5'-CAC[GA]TG-3'. The MYC:MAX complex is a transcriptional activator, whereas the MAD:MAX complex is a transcriptional repressor. Max homodimer bind DNA but is transcriptionally inactive. Targeted deletion of max results in early embryonic lethality in mice.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILDKATEYIQYMRRKNHTHQQDIDDLKRQN 92
Cdd:cd11406     1 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILKKATEYIQYMRRKNHTHQQDIDDLKRQN 69

Helix-loop-helix DNA-binding domain;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSL-QGEKASRAQILDKATEYIQYMR 75
Cdd:pfam00010   1 RREAHNERERRRRDRINDAFDELRELLPTLpPDKKLSKAEILRLAIEYIKHLQ 53

helix loop helix domain;

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|...
gi 2244985492   29 NALERKRRDHIKDSFHSLRDSVPSL-QGEKASRAQILDKATEYIQYMRRKNHT 80
Cdd:smart00353   1 NARERRRRRKINEAFDELRSLLPTLpKNKKLSKAEILRLAIEYIKSLQEELQK 53

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in Max-like protein X (Mlx) family; Mlx, also termed Class D basic helix-loop-helix protein 13 (bHLHd13), or Max-like bHLHZip protein, or protein BigMax, or transcription factor-like protein 4, is a Max-like bHLHZip transcription regulator that interacts with the Max network of transcription factors. It forms a sequence-specific DNA-binding protein complex with some member of Mad family (Mad1 and Mad4) and Mondo family but not the Myc family and bind the E-box DNA to control transcription. The family also includes Saccharomyces cerevisiae INO4, which is a bHLH transcriptional activator of phospholipid synthetic genes (such as INO1, CHO1/PSS, CHO2/PEM1, OPI3/PEM2, etc.). It is required for de-repression of phospholipid biosynthetic gene expression in response to inositol deprivation in yeast.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILDKATEYIQYMrrknhthQQDIDDLKRQNALLEQQ 98
Cdd:cd11404     2 RRLNHVRSEKKRRELIKKGYDELCALVPGLDPQKRTKADILQKAADWIQEL-------KEENEKLEEQLDELKEA 69

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in sterol regulatory element-binding protein (SREBP) family and similar proteins; The SREBP family includes SREBP1 and SREBP2, which are bHLHzip transcriptional activator of genes encoding proteins essential for cholesterol biosynthesis/uptake and fatty acid biosynthesis. SREBP1 and SREBP2 are principally found in the liver and in adipocytes and made up of an N-terminal transcription factor portion (composed of an activation domain, a bHLHzip domain, and a nuclear localization signal), a hydrophobic region containing two membrane spanning regions, and a C-terminal regulatory segment. They recognize a symmetric sterol regulatory element (TCACNCCAC) instead of E-box. The family also includes Saccharomyces cerevisiae transcription factor HMS1 (also termed high-copy MEP suppressor protein 1) and serine-rich protein TYE7. HMS1 is a putative bHLHzip transcription factor involved in exit from mitosis and pseudohyphal differentiation. TYE7, also termed basic-helix-loop-helix protein SGC1, is a putative bHLHzip transcription activator required for Ty1-mediated glycolytic gene expression. TYE7 N-terminal is extremely rich in serine residues. It binds DNA on E-box motifs, 5'-CANNTG-3'. TYE7 is not essential for growth.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQ----------------GEKASRAQILDKATEYIQYMRRKNHTHQQDIDD 87
Cdd:cd11395     3 KRLPHNAIEKRYRSNLNTKIERLRDAIPSLRspegksddgglgglapTTKLSKATILTKAIEYIRHLEQENERLEEENEE 82

                  ....
gi 2244985492  88 LKRQ 91
Cdd:cd11395    83 LRQQ 86

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in USF/MITF family; The USF (upstream stimulatory factor)/MITF (microphthalmia-associated transcription factor) family includes two bHLHzip transcription factor subfamilies. USFs are ubiquitously expressed and key regulators of a wide number of gene regulation networks, including the stress and immune responses, cell cycle and proliferation, lipid and glucid metabolism. USFs recruit chromatin remodeling enzymes and interact with co-activators and the members of the transcription pre-initiation complex. USFs interact with high affinity to E-box regulatory elements. The MITF (also known as microphthalmia-TFE, or MiT) subfamily comprises four genes in mammals (MITF, TFE3, TFEB, and TFEC); each gene has different functions. MITF is involved in neural crest melanocytes development as well as the pigmented retinal epithelium. TFEB is required for vascularization of the mouse placenta. TFE3 is involved in B cell function. TFEC regulates gene expression in macrophages. The MITF subfamily proteins can form homodimers or heterodimers with each other but not with other bHLH or bHLHzip proteins.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 2244985492  28 HNALERKRRDHIKDSFHSLRDSVPSLQGE----KASRAQILDKATEYIQYMRRKNHT 80
Cdd:cd11387     2 HNAVERRRRDNINEKIQELGSLVPPSRLEtkdlKPNKGSILSKAVEYIRELQNQNQE 58

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in MLX-interacting protein (MLXIP), MLX-interacting protein-like (MLXIPL) and similar proteins; The family includes MLXIP and MLXIPL. MLXIP, also termed Class E basic helix-loop-helix protein 36 (bHLHe36), or transcriptional activator MondoA, is a bHLHZip transcriptional activator that binds DNA as a heterodimer with Mlx. It binds to the canonical E box sequence 5'-CACGTG-3' and plays a role in transcriptional activation of glycolytic target genes. MLXIP is most highly expressed in skeletal muscle and functions as an indirect glucose sensor, by sensing glucose 6-phosphate and shuttling between the nucleus and the cytoplasm. MLXIPL, also termed carbohydrate-responsive element-binding protein (ChREBP), or Class D basic helix-loop-helix protein 14 (bHLHd14), or MLX interactor, or WS basic-helix-loop-helix leucine zipper protein (WS-bHLH), or Williams-Beuren syndrome chromosomal region 14 protein (WBSCR14), is a bHLHZip transcriptional factor integral to the regulation of glycolysis and lipogenesis in the liver. It forms heterodimers with the bHLHZip protein Mlx to bind the DNA sequence 5'-CACGTG-3'.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGE---KASRAQILDKATEYIQYMRRKNHTHQQDIDDLKRQ 91
Cdd:cd11405     3 RRLSHISAEQKRRFNIKSGFDTLQSLIPSLGQNpnqKVSKAAMLQKAAEYIKSLKRERQQMQEEAEQLRQE 73

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in transcription factor AP-4 (TFAP4) and similar proteins; TFAP4, also termed activating enhancer-binding protein 4, or Class C basic helix-loop-helix protein 41 (bHLHc41), is a bHLHzip transcription factor that activates both viral and cellular genes involved in the regulation of cellular proliferation, stemness, and epithelial-mesenchymal transition by binding to the symmetrical DNA sequence 5'-CAGCTG-3'.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILDKATEYIQYMRRKN 78
Cdd:cd11419     4 RREIANSNERRRMQSINAGFQSLRTLLPHCDGEKLSKAAILQQTAEYIFSLEQEK 58

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in Schizosaccharomyces pombe ESC1 (spESC1) and similar proteins; spESC1 is a bHLHzip protein with homology to human MyoD and Myf-5 myogenic differentiation inducers. It is involved in the sexual differentiation process.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 2244985492  25 RAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILDKATEYIQYMRRKNHTHQQDIDDLK 89
Cdd:cd19690     1 RVSHKLAERKRRKEMKELFEDLRDALPQERGTKASKWEILTKAISYIQQLKRHIRELRSEVNDLR 65

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in basic helix-loop-helix domain-containing protein USF3 and similar proteins; USF3, also termed upstream transcription factor 3, is a bHLHzip protein that is involved in the negative regulation of epithelial-mesenchymal transition, the process by which epithelial cells lose their polarity and adhesion properties to become mesenchymal cells with enhanced migration and invasive properties.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILDKATEYIQYMRRKN 78
Cdd:cd18910     5 KRESHNEVERRRKDKINAGINKIGELLPDRDAKKQSKNMILEQAYKYIVELKKKN 59

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in sterol regulatory element-binding protein (SREBP) family; The SREBP family includes SREBP1 and SREBP2, which are bHLHzip transcriptional activator of genes encoding proteins essential for cholesterol biosynthesis/uptake and fatty acid biosynthesis. SREBP1 and SREBP2 are principally found in the liver and in adipocytes and made up of an N-terminal transcription factor portion (composed of an activation domain, a bHLHzip domain, and a nuclear localization signal), a hydrophobic region containing two membrane spanning regions, and a C-terminal regulatory segment. They recognize a symmetric sterol regulatory element (TCACNCCAC) instead of E-box.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGeKASRAQILDKATEYIQYMRRKNHTHQQDIDDLKRQN 92
Cdd:cd11394     6 KRSAHNAIEKRYRSSINDRIIELKDLVVGPDA-KMNKSAVLRKAIDYIRYLQKVNQKLKQENMALKKAL 73

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in the Mad family; Members of the Mad family (Mad1, Mxi, Mad3, and Mad4) bear the bHLHzip domain (also known as basic-helix-loop-helix-leucine-zipper or bHLH-LZ domain), which mediates heterodimerization to Max and the sequence-specific DNA binding ability to E-box DNA. Mad family proteins can repress transcription at the E-box through their interaction with co-repressors. Mad family proteins antagonize Myc function in transactivation and transformation and they are growth/tumor suppressors. The developmental phenotypes of the individual Mad family member knockout mice are relatively mild- all these mice have been shown to be viable and normal.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 2244985492  25 RAHHNALERKRRDHIKDSFHSLRDSVPSlqGEKASRAQ---ILDKATEYIQYMRRKNHTHQQDIDDLKRQNALL 95
Cdd:cd11401     1 RSTHNELEKNRRAHLRLCLERLKELVPL--GPDATRHTtlsLLTKAKAYIKNLEDKEKRQRQQKEQLRREQREL 72

tissue specific basic helix-loop-helix (bHLH-TS) domain family; Tissue specific bHLH domain family includes transcription regulators whose expression are restricted to certain tissues. They are involved in cell-fate determination and process in neurogenesis, cardiogenesis, myogenesis, and hematopoiesis and include proteins from myogenic regulatory factor (MRF) family, twist-related protein (TWIST) family, scleraxis-like family, heart- and neural crest derivatives-expressed protein (HAND) family, helix-loop-helix protein (HEN) family, musculin-like family, germline alpha (FIGLA) family, T-cell acute lymphocytic leukemia protein/ lymphoblastic leukemia-derived sequence (TAL/LYL) family, ovary, uterus and testis protein (OUT) family, mesoderm posterior protein (Mesp) family, muscle, intestine and stomach expression 1 (MIST-1) family, protein atonal homologs (ATOH) family, neurogenin (NGN) family, neurogenic differentiation factor (NeuroD) family, achaete-scute complex-like (ASCL) family, Fer3-like protein (FERD3L)-like family, and Oligodendrocyte lineage genes (OLIG) family of transcription factors.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 2244985492  25 RAHHNALERKRRDHIKDSFHSLRDSVPSLQ-GEKASRAQILDKATEYIQYMRR 76
Cdd:cd11390     1 RNAANARERRRMHDLNDAFEALRKVLPTVPpDKKLSKIETLRLAINYIAALSD 53

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in sterol regulatory element-binding protein 2 (SREBP2) and similar proteins; SREBP2, also termed Class D basic helix-loop-helix protein 2 (bHLHd2), or sterol regulatory element-binding transcription factor 2 (SREBF2), is a member of a family of bHLHzip transcription factors that recognize sterol regulatory element 1 (SRE-1). It acts as a transcription activator of cholesterol biosynthesis.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2244985492  23 DKRAHHNALERKRRDHIKDSFHSLRDSVPSlQGEKASRAQILDKATEYIQYMRRKNHTHQQDIDDLKRQN 92
Cdd:cd18922     5 ERRTTHNIIEKRYRSSINDKIIELKDLVMG-TDAKMHKSGVLRKAIDYIKYLQQVNHKLRQENMALKLAN 73

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in upstream stimulatory factors, USF1, USF2 and similar proteins; Upstream stimulatory factor 1 and 2 (USF-1 and USF-2) are members of bHLHzip transcription factor family. USFs are ubiquitously expressed and key regulators of a wide number of gene regulation networks, including the stress and immune responses, cell cycle and proliferation, lipid and glucid metabolism. USFs recruit chromatin remodeling enzymes and interact with co-activators and the members of the transcription pre-initiation complex. USFs interact with high affinity to E-box regulatory elements.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2244985492  28 HNALERKRRDHIKDSFHSLRDSVPSLQ----GEKASRAQILDKATEYIQYMRRKNH 79
Cdd:cd11396     2 HNEVERRRRDKINNWIVKLAKIVPDCEkdnsKQGQSKGGILSKACDYIQELRSQNE 57

basic Helix-Loop-Helix (bHLH) domain found in Arabidopsis thaliana MYC1 and similar proteins; MYC1, also termed AtbHLH12, or EN 58, acts as a transcription activator, when associated with MYB75/PAP1 or MYB90/PAP2.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 2244985492  28 HNALERKRRDHIKDSFHSLRDSVPSLQgeKASRAQILDKATEYIQYMRRK 77
Cdd:cd18918     1 LFATERERREKLNEKFSDLRNLIPNPT--KNDRASILSDAIKYINELQRT 48

basic helix-loop-helix (bHLH) domain found in twist-related protein (TWIST) family; The TWIST family includes TWIST1 and TWIST2, which are highly homologous bHLH transcription factors that promote epithelial-mesenchymal transition (EMT) during development and tumor metastasis. They are involved in the negative regulation of cellular determination and in the differentiation of several lineages, including myogenesis, osteogenesis, and neurogenesis. TWIST factors express in broad partially-overlapping patterns during embryo development and dimerize with a broad sets of dimer partners that form numerous unique transcriptional complexes to regulate embryonic development.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILDKATEYIQYMRR 76
Cdd:cd11464     1 QRVLANVRERQRTQSLNEAFTSLRKIIPTLPSDKLSKIQTLKLAARYIDFLYQ 53

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in Saccharomyces cerevisiae centromere-binding protein 1 (CBP-1) and similar proteins; CBP-1, also termed centromere promoter factor 1 (CPF1), or centromere-binding factor 1 (CBF1), is a bHLHzip protein that is required for chromosome stability and methionine prototrophy. It binds as a homodimer to the centromere DNA elements I (CDEI, GTCACATG) region of the centromere that is required for optimal centromere function.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKaSRAQILDKATEYIQYMRRKNH 79
Cdd:cd11398     7 RRDNHKEVERRRRENINEGINELAALVPGNAREK-NKGAILARAVEYIQELQETEA 61

basic helix-loop-helix (bHLH) domain found in protein atonal homolog 7 (ATOH7) and similar proteins; ATOH7, also termed Class A basic helix-loop-helix protein 13 (bHLHa13), or helix-loop-helix protein hATH-5 (hATH5), or Math5, is a bHLH transcription factor involved in the differentiation of retinal ganglion cells.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 2244985492  17 RFQSAADKRAHHNALERKRRDHIKDSFHSLRDSVPSL-QGEKASRAQILDKATEYIQYMRR 76
Cdd:cd19714     1 RLESAARRRLAANARERRRMQGLNTAFDRLRKVVPQWgQDKKLSKYETLQMALSYIMALTR 61

basic Helix-Loop-Helix (bHLH) domain found in Saccharomyces cerevisiae INO4 and similar proteins; INO4 is a bHLH transcriptional activator of phospholipid synthetic genes (such as INO1, CHO1/PSS, CHO2/PEM1, OPI3/PEM2, etc.). It is required for de-repression of phospholipid biosynthetic gene expression in response to inositol deprivation in yeast. INO4 dimerizes with INO2 and binds to an UAS DNA element to control expression of the genes whose expression is inositol-responsive.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQG-EKASRAQILDKATEYIQYMRRKN 78
Cdd:cd11403     2 KKENHISSEHKRREAIREGFDRLCAIVPALSSsQSRSEAVVYVKTVEYLKELYERR 57

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster achaete-scute complex (AS-C) proteins, achaete-scute-like proteins, ASCL1-2, and similar proteins; This subfamily includes Drosophila melanogaster AS-C proteins and two ASCL family of transcription factors, ASCL-1 and ASCL-2. Drosophila melanogaster AS-C proteins includes lethal of scute (also known as achaete-scute complex protein T3 or AST3), scute (also known as achaete-scute complex protein T4 or AST4), achaete (also known as achaete-scute complex protein T5 or AST5), and asense (also known as achaete-scute complex protein T8 or AST8). They are involved in the determination of the neuronal precursors in the peripheral nervous system and the central nervous system, as well as in sex determination and dosage compensation. ASCL-1, also termed Class A basic helix-loop-helix protein 46 (bHLHa46), or achaete-scute homolog 1 (ASH-1), or mammalian achaete scute homolog 1 (Mash1), is expressed in subsets of neural progenitors in both the central and peripheral nervous system. It plays a key role in neuronal differentiation and specification in the nervous system. ASCL-2, also termed achaete-scute homolog 2 (ASH-2), or Class A basic helix-loop-helix protein 45 (bHLHa45), or mammalian achaete scute homolog 2 (Mash2), is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 2244985492  26 AHHNALERKRRDHIKDSFHSLRDSVPSL-QGEKASRAQILDKATEYIQYMRR 76
Cdd:cd19723     3 ARRNERERNRVKLVNLGFATLREHVPNGrANKKMSKVETLRSAVEYIRQLQQ 54

basic helix-loop-helix (bHLH) domain found in factor in the germline alpha (FIGLA) and similar proteins; FIGLA, also termed FIGalpha, or Class C basic helix-loop-helix protein 8 (bHLHc8), or folliculogenesis-specific basic helix-loop-helix protein, or transcription factor FIGa, is a germ-cell-specific bHLH transcription factor expressed abundantly in female and less so in male germ cells. It is essential for primordial follicle formation and expression of many genes required for folliculogenesis, fertilization and early embryonic survival. FIGLA knockout mice cannot form primordial follicles and lose oocytes rapidly after birth, whereas male gonads are unaffected.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 2244985492  29 NALERKRRDHIKDSFHSLRDSVP-SLQGEKASRAQILDKATEYIQYMRR 76
Cdd:cd11422     5 NARERERVRNLNSGFSKLRRIVPlIPRDRKPSKVDTLKGATEYIRLLQR 53

basic helix-loop-helix (bHLH) domain found in heart- and neural crest derivatives-expressed protein 1 (HAND1) and similar proteins; HAND1, also termed Class A basic helix-loop-helix protein 27 (bHLHa27), or extraembryonic tissues, heart, autonomic nervous system and neural crest derivatives-expressed protein 1 (eHAND), is a bHLH transcription factor that plays an essential role in both trophoblast-giant cells differentiation and in cardiac morphogenesis.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 2244985492  32 ERKRRDHIKDSFHSLRDSVPSLQGE-KASRAQILDKATEYIQYM 74
Cdd:cd18952    10 ERRRTESINSAFAELRECIPNVPADtKLSKIKTLRLATSYIAYL 53

basic helix-loop-helix (bHLH) domain found in protein atonal homolog 8 (ATOH8) and similar proteins; ATOH8, also termed Class A basic helix-loop-helix protein 21 (bHLHa21), or helix-loop-helix protein hATH-6 (hATH6), is a bHLH shear-stress-responsive transcription factor expressed in activated satellite cells and proliferating myoblasts of human skeletal muscle tissue. It regulates endothelial cell proliferation, migration and tube-like structures formation. ATOH8 binds a palindromic (canonical) core consensus DNA sequence 5'-CANNTG- 3' known as an E-box element, possibly as a heterodimer with other bHLH proteins.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 2244985492  23 DKRAHHNALERKRRDHIKDSFHSLRDSVPSL-QGEKASRAQILDKATEYI 71
Cdd:cd11421     7 QRRIEANARERTRVHTISAAFEALRKAVPSYsYNQKLSKLAILRIACSYI 56

basic helix-loop-helix-orange (bHLH-O) domain found in hairy and enhancer of split (HES)-related repressor protein (HERP)-like family; The HERP-like family includes bHLH-O transcriptional regulators that are related to the Drosophila hairy and Enhancer-of-split proteins. They contain a basic helix-loop-helix (bHLH) domain with an invariant glycine residue in its basic region, an orange domain in the central region and YXXW sequence motif at its C-terminal region. HERP proteins (HEY1, HEY2 and HEYL) act as downstream effectors of Notch signaling. They are involved in cardiovascular development and have roles in somitogenesis, myogenesis and gliogenesis. Hairy and enhancer of split-related protein HELT is a transcriptional repressor expressed in the developing central nervous system. It binds preferentially to the canonical E box sequence 5'-CACGCG-3' and regulates neuronal differentiation and/or identity. Differentially expressed in chondrocytes proteins, DEC1 and DEC2, are widely expressed in both embryonic and adult tissues and have been implicated in apoptosis, cell proliferation, and circadian rhythms, as well as malignancy in various cancers. Drosophila melanogaster protein clockwork orange (Cwo) is also included in this family. It is involved in the regulation of Drosophila circadian rhythms. It functions as both an activator and a repressor of clock gene expression.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2244985492  28 HNALERKRRDHIKDSFHSLRDSVP----SLQGEKASRAQILDKATEYIQYM 74
Cdd:cd11389     1 HKVIEKRRRDRINESLAELRRLVPearkSKGSGKLEKAEILEMTLQHLKAL 51

basic helix-loop-helix (bHLH) domain found in twist-related protein 2 (TWIST2) and similar proteins; TWIST2, also termed Class A basic helix-loop-helix protein 39 (bHLHa39), or Dermis-expressed protein 1, or Dermo-1, is a bHLH transcription factor that regulates the development of mesenchymal tissues and plays a critical role in embryogenesis. It binds to the E-box consensus sequence 5'-CANNTG-3' as a heterodimer and inhibits transcriptional activation by MYOD1, MYOG, MEF2A and MEF2C.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 2244985492  18 FQSAADKRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKASRAQILDKATEYIQYMRRKNHTHQQD 84
Cdd:cd19700    11 YEELQSQRILANVRERQRTQSLNEAFAALRKIIPTLPSDKLSKIQTLKLAARYIDFLYQVLQSDEMD 77

basic helix-loop-helix (bHLH) domain found in Fer3-like protein (FERD3L), pancreas transcription factor 1 subunit alpha (PTF1A) and similar proteins; The family corresponds to a group of bHLH transcription factors, including FERD3L and PTF1A. FERD3L, also termed basic helix-loop-helix protein N-twist, or Class A basic helix-loop-helix protein 31 (bHLHa31), or nephew of atonal 3 (NATO3), or Neuronal twist (NTWIST), is expressed in the developing central nervous system (CNS). It regulates floor plate (FP) cells development. FP is a critical organizing center located at the ventral-most midline of the neural tube. FERD3L binds to the E-box and functions as inhibitor of transcription. PTF1A, also termed Class A basic helix-loop-helix protein 29 (bHLHa29), or pancreas-specific transcription factor 1a, or bHLH transcription factor p48, or p48 DNA-binding subunit of transcription factor PTF1 (PTF1-p48), is implicated in the cell fate determination in various organs. It binds to the E-box consensus sequence 5'-CANNTG-3' and plays a role in early and late pancreas development and differentiation.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 2244985492  24 KRAHHNALERKRRDHIKDSFHSLRDSVPSLQGEKA-SRAQILDKATEYIQYM 74
Cdd:cd19686     1 QRQAANIRERKRMRSINDAFDGLRRHIPTFPYEKRlSKVDTLRLAIQYINFL 52