Helix-loop-helix DNA-binding domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYI 132
Cdd:pfam00010   1 RREAHNERERRRRDRINDAFDELRELLPTLPPDKKLSKAEILRLAIEYI 49

basic helix-loop-helix (bHLH) domain found in neurogenin-1 (NGN-1) and similar proteins; NGN-1, also termed Class A basic helix-loop-helix protein 6 (bHLHa6), or neurogenic basic-helix-loop-helix protein, or neurogenic differentiation factor 3 (NeuroD3), is a neural-specific bHLH transcription factor involved in the initiation of neuronal differentiation. It activates transcription by binding to the E box (5'-CANNTG-3').

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1034568349  68 RSRPKSELALSKQRRSRRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTLRIADH 144
Cdd:cd19716     1 RSRVKNEALLHTIKKSRRVKANDRERNRMHNLNAALDELRSVLPSFPDDTKLTKIETLRFAHNYIWALSETLRLADQ 77

basic helix-loop-helix (bHLH) domain found in neurogenin-2 (NGN-2) and similar proteins; NGN-2, also termed Class A basic helix-loop-helix protein 8 (bHLHa8), or protein atonal homolog 4 (ATOH4), is a neural-specific bHLH transcription factor required for sensory neurogenesis. It activates transcription by binding to the E box (5'-CANNTG-3').

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1034568349  79 KQRRSRRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTLRIAD 143
Cdd:cd19717     5 KIKKTRRVKANNRERNRMHNLNAALDSLREVLPTFPEDAKLTKIETLRFAHNYIWALSETLRLAD 69

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor (NeuroD) family; The NeuroD family includes NeuroD1, NeuroD2, NeuroD4 and NeuroD6. NeuroD1, also termed Class A basic helix-loop-helix protein 3 (bHLHa3), is a neuronal bHLH transcription factor involved in the development and maintenance of the endocrine pancreas and neuronal elements. It acts as an essential regulator of glutamatergic neuronal differentiation. Loss of NeuroD1 causes ataxia, cerebellar hypoplasia, sensorineural deafness, and severe retinal dystrophy in mice. NeuroD2, also termed Class A basic helix-loop-helix protein 1 (bHLHa1), or NeuroD-related factor (NDRF), is a neuronal calcium-dependent bHLH transcription factor that induces neuronal differentiation and promotes neuronal survival. It plays a central role in thalamocortical synaptic maturation. NeuroD2 mediates calcium-dependent transcription activation by binding to E box-containing promoter. NeuroD4, also termed Class A basic helix-loop-helix protein 4 (bHLHa4), or protein atonal homolog 3 (ATH-3), or Atoh3, or Math-3, is a bHLH transcriptional activator that mediates neuronal differentiation. NeuroD6, also termed Class A basic helix-loop-helix protein 2 (bHLHa2), or protein atonal homolog 2 (ATH-2), or Atoh2, or Math2, or Nex1, is a neurogenic bHLH transcription factor involved in neuronal development, differentiation, and survival in Alzheimer's disease (AD) brains of both cohorts. It plays an integrative role in coordinating increase in mitochondrial mass with cytoskeletal remodeling, suggesting that it may act as a co-regulator of neuronal differentiation and energy metabolism.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1034568349  85 RKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd11427     1 RVKANARERNRMHGLNDALDNLRKVVPCYSKTQKLSKIETLRLARNYIWALSEIL 55

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor 2 (NeuroD2) and similar proteins; NeuroD2, also termed Class A basic helix-loop-helix protein 1 (bHLHa1), or NeuroD-related factor (NDRF), is a neuronal calcium-dependent bHLH transcription factor that induces neuronal differentiation and promotes neuronal survival. It plays a central role in thalamocortical synaptic maturation. NeuroD2 mediates calcium-dependent transcription activation by binding to E box-containing promoter.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034568349  48 EAEEGGCRGAPRklRARRGGRSRPKSELALSKQRRSRRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRF 127
Cdd:cd19720     1 EEEEGLEEADGE--RPKKRGPKKRKMTKARLERSKLRRQKANARERNRMHDLNSALDNLRKVVPCYSKTQKLSKIETLRL 78

                          90
                  ....*....|...
gi 1034568349 128 AHNYIWALTQTLR 140
Cdd:cd19720    79 AKNYIWALSEILR 91

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor 1 (NeuroD1) and similar proteins; NeuroD1, also termed Class A basic helix-loop-helix protein 3 (bHLHa3), is a neuronal bHLH transcription factor involved in the development and maintenance of the endocrine pancreas and neuronal elements. It acts as an essential regulator of glutamatergic neuronal differentiation. Loss of NeuroD1 causes ataxia, cerebellar hypoplasia, sensorineural deafness, and severe retinal dystrophy in mice.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1034568349  62 RARRGGRSRPKSELALSKQRRSRRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTLR 140
Cdd:cd19719     6 KPKRRGPKKKKMTKARLERFKMRRMKANARERNRMHGLNAALDNLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEILR 84

Helix-loop-helix DNA-binding domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYI 132
Cdd:pfam00010   1 RREAHNERERRRRDRINDAFDELRELLPTLPPDKKLSKAEILRLAIEYI 49

basic helix-loop-helix (bHLH) domain found in muscle, intestine and stomach expression 1 (MIST-1) and similar proteins; MIST-1, also termed Class A basic helix-loop-helix protein 15 (bHLHa15), or Class B basic helix-loop-helix protein 8 (bHLHb8), is a bHLH transcription factor expressed in pancreatic acinar cells and other serous exocrine cells. It is essential for cytoskeletal organization and secretory activity. It also functions as a potent endoplasmic reticulum (ER) stress-inducible transcriptional regulator. MIST-1 is capable of binding to E-box (CANNTG) motifs as a homodimer or a heterodimer with E-proteins (E12 and E47) to regulate transcription.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19711     1 RRLESNERERQRMHKLNNAFQALREVIPHVRAEKKLSKIETLTLAKNYIKSLTTTI 56

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 1034568349  85 RKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19686     2 RQAANIRERKRMRSINDAFDGLRRHIPTFPYEKRLSKVDTLRLAIQYINFLTELL 56

basic helix-loop-helix (bHLH) domain found in Oligodendrocyte lineage genes (OLIG) family of transcription factors; The OLIG family includes three bHLH transcription factors, Oligo1-3, which are expressed in both the developing and mature central nervous system. Oligo1 and Oligo2 are expressed in a nervous tissue-specific manner, but Oligo3 is found mainly in non-neural tissues. Oligo (also known as Olig) have key roles in the specification of motor neurons, dorsal interneurons, and oligodendrocytes. Oligo1, also termed Class B basic helix-loop-helix protein 6 (bHLHb6), or Class E basic helix-loop-helix protein 21 (bHLHe21), promotes formation and maturation of oligodendrocytes, especially within the brain. Oligo2, also termed Class B basic helix-loop-helix protein 1 (bHLHb1), or Class E basic helix-loop-helix protein 19 (bHLHe19), or protein kinase C-binding protein 2, or protein kinase C-binding protein RACK17, is required for oligodendrocyte and motor neuron specification in the spinal cord, as well as for the development of somatic motor neurons in the hindbrain. It cooperates with OLIG1 to establish the MN progenitors (pMN) domain of the embryonic neural tube. Oligo3, also termed Class B basic helix-loop-helix protein 7 (bHLHb7), or Class E basic helix-loop-helix protein 20 (bHLHe20), is expressed in the ventricular zone of the dorsal alar plate of the hindbrain and involved in regulating the development of dorsal and ventral spinal cord. It may determine the distinct specification program of class A neurons in the dorsal part of the spinal cord and suppress specification of class B neurons. This family also includes two OLIG-related bHLH transcription factors, bHLHe22 and bHLHe23. bHLHe22, also termed Class B basic helix-loop-helix protein 5 (bHLHb5), or trinucleotide repeat-containing gene 20 protein, is a neural-specific transcriptional repressor that is expressed in both excitatory (unipolar brush cells) and inhibitory neurons (cartwheel cells) of the dorsal cochlear nucleus (DCN) during development. It is important for the proper development and/or survival of a number of neural cell types. bHLHe23, also termed Class B basic helix-loop-helix protein 4 (bHLHb4), is expressed in rod bipolar cells and is required for rod bipolar cell maturation. bHLHe23 have roles in spinal interneuron differentiation by mechanisms linked to the Notch signaling pathway. It modulates the expression of genes required for the differentiation and/or maintenance of pancreatic and neuronal cell types.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1034568349  85 RKKANDRERNRMHNLNSALDALRGVLPTF--PDDAKLTKIETLRFAHNYIWALTQTLR 140
Cdd:cd11429     1 RLKINSRERKRMHDLNSALDGLRSVMPYAqgPSVRKLSKIATLLLARNYILMLTQALE 58

basic helix-loop-helix (bHLH) domain found in protein atonal homolog 1 (ATOH1) and similar proteins; ATOH1, also termed Class A basic helix-loop-helix protein 14 (bHLHa14), or helix-loop-helix protein hATH-1 (hATH1), or Math1, or Cath1, is a proneural bHLH transcription factor that is essential for inner ear hair cell differentiation. It dimerizes with E47 and activates E-box (CANNTG) dependent transcription. ATOH1 is a mammalian homolog of the Drosophila melanogaster gene atonal and mouse atonal homolog 1 (Math1).

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1034568349  81 RRSRRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19713     3 QKQRRLAANARERRRMHGLNHAFDQLRNVIPSFNNDKKLSKYETLQMAQIYINALSELL 61

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster protein dimmed and similar proteins; Dimmed, also termed DIMM, is a bHLH transcription factor that regulates neurosecretory (NS) cell function and neuroendocrine cell fate in Drosophila.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALT 136
Cdd:cd19712     1 RRLESNERERMRMHSLNDAFQGLREVIPHVNAERKLSKIETLTLAKNYIKALT 53

basic helix-loop-helix (bHLH) domain found in Fer3-like protein (FERD3L) and similar proteins; 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 a bHLH transcription factor 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.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1034568349  83 SRRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd11415     8 AQRQAANIRERRRMFNLNEAFDKLRKKVPTFAYEKRLSRIETLRLAIVYISFMTDLL 64

basic helix-loop-helix (bHLH) domain found in oligodendrocyte transcription factors, Oligo2, Oligo3 and similar proteins; The family includes two bHLH transcription factors, Oligo2 and Oligo3. Oligo2, also termed Class B basic helix-loop-helix protein 1 (bHLHb1), or Class E basic helix-loop-helix protein 19 (bHLHe19), or protein kinase C-binding protein 2, or protein kinase C-binding protein RACK17, is required for oligodendrocyte and motor neuron specification in the spinal cord, as well as for the development of somatic motor neurons in the hindbrain. It cooperates with OLIG1 to establish the MN progenitors (pMN) domain of the embryonic neural tube. Oligo3, also termed Class B basic helix-loop-helix protein 7 (bHLHb7), or Class E basic helix-loop-helix protein 20 (bHLHe20), is expressed in the ventricular zone of the dorsal alar plate of the hindbrain and involved in regulating the development of dorsal and ventral spinal cord. It may determine the distinct specification program of class A neurons in the dorsal part of the spinal cord and suppress specification of class B neurons.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1034568349  85 RKKANDRERNRMHNLNSALDALRGVLPTF--PDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19725     2 RLKINSRERKRMHDLNSALDGLREVMPYAhgPSVRKLSKIATLLLARNYILMLTNSL 58

basic helix-loop-helix (bHLH) domain found in twist-related protein 1 (TWIST1) and similar proteins; TWIST1, also termed Class A basic helix-loop-helix protein 38 (bHLHa38), or H-twist, is a bHLH transcriptional regulator that inhibits myogenesis by sequestrating E proteins, inhibiting trans-activation by MEF2, and inhibiting DNA-binding by MYOD1 through physical interaction. It also represses expression of proinflammatory cytokines such as TNFA and IL1B. In addition, TWIST1 is involved in cancer development and progression.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1034568349  79 KQRRSRRKKANDRERNRMHNLNSALDALRGVLPTFPDDaKLTKIETLRFAHNYIWALTQTLR 140
Cdd:cd11412     7 EELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQ 67

basic helix-loop-helix (bHLH) domain found in achaete-scute complex-like (ASCL) family; The achaete-scute complex-like (ASCL, also known as achaete-scute complex homolog or ASH) family of bHLH transcription factors, ASCL1-5, have been implicated in cell fate specification and differentiation. They are critical for proper development of the nervous system. The deregulation of ASCL plays a key role in psychiatric and neurological disorders. 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 a neural-specific bHLH transcription factor that 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 a bHLH transcription factor that is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves. ASCL-3, also termed Class A basic helix-loop-helix protein 42 (bHLHa42), or bHLH transcriptional regulator Sgn-1, or achaete-scute homolog 3 (ASH-3), is a bHLH transcription factor specifically localized in the duct cells of the salivary glands. It may act as transcriptional repressor that inhibits myogenesis. The family also includes Drosophila melanogaster achaete-scute complex (AS-C) proteins, which consists of 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.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd11418     1 RVARRNERERRRVQAVNDAFDRLRQHVPYLKRRKKLSKVKTLRRAIEYIRHLQKLL 56

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 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDaKLTKIETLRFAHNYIWALTQTLR 140
Cdd:cd11464     1 QRVLANVRERQRTQSLNEAFTSLRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLR 56

basic helix-loop-helix (bHLH) domain found in heart- and neural crest derivatives-expressed protein (HAND) family; The HAND family includes two bHLH transcription factors, HAND1 and HAND2. 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), plays an essential role in both trophoblast-giant cells differentiation and in cardiac morphogenesis. HAND2, also termed Class A basic helix-loop-helix protein 26 (bHLHa26), or deciduum, heart, autonomic nervous system and neural crest derivatives-expressed protein 2 (dHAND), is essential for cardiac morphogenesis, particularly for the formation of the right ventricle and of the aortic arch arteries.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd11466     1 RRGSANKKERRRTQSINSAFADLRECIPNVPADTKLSKIKTLRLATSYIAYLMDVL 56

basic helix-loop-helix (bHLH) domain found in Class E basic helix-loop-helix protein bHLHe22, bHLHe23 and similar proteins; The family includes two OLIG-related bHLH transcription factors, bHLHe22 and bHLHe23. bHLHe22, also termed Class B basic helix-loop-helix protein 5 (bHLHb5), or trinucleotide repeat-containing gene 20 protein, is a neural-specific transcriptional repressor that is expressed in both excitatory (unipolar brush cells) and inhibitory neurons (cartwheel cells) of the dorsal cochlear nucleus (DCN) during development. It is important for the proper development and/or survival of a number of neural cell types. bHLHe23, also termed Class B basic helix-loop-helix protein 4 (bHLHb4), is expressed in rod bipolar cells and is required for rod bipolar cell maturation. bHLHe23 have roles in spinal interneuron differentiation by mechanisms linked to the Notch signaling pathway. It modulates the expression of genes required for the differentiation and/or maintenance of pancreatic and neuronal cell types.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 1034568349  85 RKKANDRERNRMHNLNSALDALRGVLPTFPDDA--KLTKIETLRFAHNYI 132
Cdd:cd11468     1 RLSINARERRRMHDLNDALDDLRAVIPYAHSPSvrKLSKIATLLLAKNYI 50

basic helix-loop-helix (bHLH) domain found in T-cell acute lymphocytic leukemia protein 2 (TAL-2) and similar proteins; TAL-2, also termed Class A basic helix-loop-helix protein 19 (bHLHa19), is a bHLH transcription factor essential for the normal brain development. It has been implicated in T-cell acute lymphoblastic leukemia.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1034568349  83 SRRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19707     1 TRKIFTNTRERWRQQNVNSAFAELRKLIPTHPPDKKLSKNEILRLAMKYINFLVKLL 57

basic helix-loop-helix (bHLH) domain found in protein lyl-1 and similar proteins; Lyl-1, also termed Class A basic helix-loop-helix protein 18 (bHLHa18), or lymphoblastic leukemia-derived sequence 1, is a proto-oncogenic bHLH transcription factor involved in T-cell acute lymphoblastic leukemia. It plays an important role in hematopoietic stem cell function and is required for the late stages of postnatal angiogenesis to limit the formation of new blood vessels, notably by regulating the activity of the small GTPase Rap1. LYL-1 deficiency induces a stress erythropoiesis.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1034568349  80 QRRSRRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTLR 140
Cdd:cd19705     2 QKVARRVFTNSRERWRQQNVNGAFAELRKLIPTHPPDKKLSKNEILRLAMKYIDFLVTLLR 62

basic helix-loop-helix (bHLH) domain found in heart- and neural crest derivatives-expressed protein 2 (HAND2) and similar proteins; HAND2, also termed Class A basic helix-loop-helix protein 26 (bHLHa26), or deciduum, heart, autonomic nervous system and neural crest derivatives-expressed protein 2 (dHAND), is a bHLH transcription factor that is essential for cardiac morphogenesis, particularly for the formation of the right ventricle and of the aortic arch arteries.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd11471     1 RRGTANRKERRRTQSINSAFAELRECIPNVPADTKLSKIKTLRLATSYIAYLMDLL 56

basic helix-loop-helix (bHLH) domain found in T-cell acute lymphocytic leukemia protein/ lymphoblastic leukemia-derived sequence (TAL/LYL) family; The TAL/LYL family includes a group of bHLH transcription factors (TAL1, TAL2 and LYL1) implicated in T cell acute leukaemia. They act as mediators of T cell leukaemogenesis. TAL-1, also termed Class A basic helix-loop-helix protein 17 (bHLHa17), or stem cell protein (SCL), or T-cell leukemia/lymphoma protein 5, is a hematopoietic-specific bHLH transcription factor that functions in embryonic and adult hematopoiesis in vertebrates. It is also required for embryonic vascular remodeling. It acts as a regulator of erythroid differentiation and binds to regulatory regions of a large cohort of erythroid genes as part of a complex with GATA-1, LMO2 and Ldb1. TAL-2, also termed Class A basic helix-loop-helix protein 19 (bHLHa19), is a bHLH transcription factor essential for the normal brain development. Lyl-1, also termed Class A basic helix-loop-helix protein 18 (bHLHa18), or lymphoblastic leukemia-derived sequence 1, is a proto-oncogenic bHLH transcription factor that plays an important role in hematopoietic stem cell function and is required for the late stages of postnatal angiogenesis to limit the formation of new blood vessels, notably by regulating the activity of the small GTPase Rap1. LYL-1 deficiency induces a stress erythropoiesis.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTLR 140
Cdd:cd11413     1 RRIFTNTRERWRQQNVNGAFAELRKLIPTHPPDKKLSKNEILRLAMKYIKFLEKILE 57

basic helix-loop-helix (bHLH) domain found in Class E basic helix-loop-helix protein 23 (bHLHe23) and similar proteins; bHLHe23, also termed Class B basic helix-loop-helix protein 4 (bHLHb4), is an OLIG-related bHLH transcription factor that is expressed in rod bipolar cells and is required for rod bipolar cell maturation. bHLHe23 have roles in spinal interneuron differentiation by mechanisms linked to the Notch signaling pathway. It modulates the expression of genes required for the differentiation and/or maintenance of pancreatic and neuronal cell types.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1034568349  79 KQRRSRRKKANDRERNRMHNLNSALDALRGVLPTF--PDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd18953     2 KEQRSLRLSINARERRRMHDLNDALDGLRSVIPYAhsPSVRKLSKIATLLLAKNYILMQAQAL 64

basic helix-loop-helix (bHLH) domain found in musculin, transcription factor 21 (TCF-21) and similar proteins; The family includes two bHLH transcription factors, musculin and transcription factor 21 (TCF-21). Musculin, also termed activated B-cell factor 1 (ABF-1), or Class A basic helix-loop-helix protein 22 (bHLHa22), is a bHLH transcription factor expressed in activated B lymphocytes. It acts as a transcription repressor capable of inhibiting the transactivation capability of TCF3/E47. Musculin may play a role in regulating antigen-dependent B-cell differentiation. The mouse homolog, musculin, is suggested to be a repressor of myogenesis that is expressed in developing muscle and in the spleen. TCF-21, also termed capsulin, or Class A basic helix-loop-helix protein 23 (bHLHa23), or epicardin, or podocyte-expressed 1 (Pod-1), is a bHLH transcription factor expressed specifically in mesodermally-derived cells that surround the epithelium of the developing gastrointestinal, genitourinary and respiratory systems during mouse embryogenesis. It may play a role in the specification or differentiation of one or more subsets of epicardial cell types.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd11423     1 QRNAANARERARMRVLSKAFSRLKTTLPWVPPDTKLSKLDTLRLAASYIAHLRQIL 56

basic helix-loop-helix (bHLH) domain found in transcription factor 21 (TCF-21) and similar proteins; TCF-21, also termed capsulin, or Class A basic helix-loop-helix protein 23 (bHLHa23), or epicardin, or podocyte-expressed 1 (Pod-1), is a bHLH transcription factor expressed specifically in mesodermally-derived cells that surround the epithelium of the developing gastrointestinal, genitourinary and respiratory systems during mouse embryogenesis. It may play a role in the specification or differentiation of one or more subsets of epicardial cell types.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1034568349  81 RRSRRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19704     1 KQVQRNAANARERARMRVLSKAFSRLKTTLPWVPPDTKLSKLDTLRLASSYIAHLRQIL 59

basic helix-loop-helix (bHLH) domain found in helix-loop-helix protein (HEN) family; The HEN family includes two neuron-specific bHLH transcription factors, HEN-1 (also known as Nhlh1 or bHLHa35 or NSCL-1) and HEN-2 (also known as Nhlh2 or bHLHa34 or NSCL-2). They may serve as DNA-binding protein that is involved in the control of cell-type determination, possibly within the developing nervous system.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1034568349  91 RERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd11414     9 RERIRVEAFNSAFAQLRKLLPTLPPDKKLSKIEILRLAICYISYLNHVL 57

basic helix-loop-helix (bHLH) domain found in the mesoderm posterior protein (Mesp) family; Mesp, a bHLH tissue specific transcription factor, acts as a key regulator of the cardiovascular transcriptional network by inducing directly and/or indirectly the expression of the majority of key cardiovascular transcription factors. The Mesp family includes two bHLH transcription factors, Mesp1 and Mesp2. Mesp1, also termed Class C basic helix-loop-helix protein 5 (bHLHc5), promotes cardiovascular differentiation during embryonic development and embryonic stem cell differentiation. Mesp2, also termed Class C basic helix-loop-helix protein 6 (bHLHc6), plays an important role in somitogenesis.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLP--TFPDDAKLTKIETLRFAHNYIWALTQTLRIADHSL 146
Cdd:cd18938     1 QRQSASEREKLRMRDLAKALHNLRRYLPpsVAPAGQSLTKIETLRLTIRYISHLSAQLGLSEESL 65

basic helix-loop-helix (bHLH) domain found in helix-loop-helix protein 1 (HEN-1) and similar proteins; HEN-1, also termed nescient helix-loop-helix 1 (Nhlh1), or Class A basic helix-loop-helix protein 35 (bHLHa35), or nescient helix loop helix 1 (NSCL-1), is a neuron-specific bHLH transcription factor that may serve as DNA-binding protein and may be involved in the control of cell-type determination, possibly within the developing nervous system.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1034568349  77 LSKQRRSRRKKAND--------RERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19701     1 LSREERRRRRRATAkyrtahatRERIRVEAFNVAFAELRKLLPTLPPDKKLSKIEILRLAICYISYLNHVL 71

basic Helix Loop Helix (bHLH) domain superfamily; bHLH proteins are transcriptional regulators that are found in organisms from yeast to humans. Members of the bHLH superfamily have two highly conserved and functionally distinct regions. The basic part is at the amino end of the bHLH that may bind DNA to a consensus hexanucleotide sequence known as the E box (CANNTG). Different families of bHLH proteins recognize different E-box consensus sequences. At the carboxyl-terminal end of the region is the HLH region that interacts with other proteins to form homo- and heterodimers. bHLH proteins function as a diverse set of regulatory factors because they recognize different DNA sequences and dimerize with different proteins. The bHLH proteins can be divided to cell-type specific and widely expressed proteins. The cell-type specific members of bHLH superfamily are involved in cell-fate determination and act in neurogenesis, cardiogenesis, myogenesis, and hematopoiesis.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1034568349  92 ERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQ 137
Cdd:cd00083     1 ERRRRDKINDAFEELKRLLPELPDSKKLSKASILQKAVEYIRELQS 46

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        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034568349  81 RRSRRKKANDRERNRMHNLNSALDALRGVLPTFpDDAKLTKIETLRFAHNYIWALTQTLR 140
Cdd:cd11419     1 RRIRREIANSNERRRMQSINAGFQSLRTLLPHC-DGEKLSKAAILQQTAEYIFSLEQEKT 59

basic helix-loop-helix (bHLH) domain found in mesogenin-1 (Msgn1) and similar proteins; Msgn1, also termed paraxial mesoderm-specific mesogenin1, or pMesogenin1 (pMsgn1), is a bHLH transcription factor required for maturation and segmentation of paraxial mesoderm. It may regulate the expression of T-box transcription factors essential for mesoderm formation and differentiation.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDAK--LTKIETLRFAHNYIWALTQTL 139
Cdd:cd18939     8 RRRKASEREKLRMRTLAEALHTLRNYLPPVYSQRGqpLTKIQTLKCTIQYISELSGLL 65

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 1 (ASCL-1) and similar proteins; 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 a neural-specific bHLH transcription factor that 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.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034568349  80 QRRSRRKKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19742     1 QQPAAVARRNERERNRVKLVNMGFATLREHVPNGAANKKMSKVETLRSAVEYIRALQQLL 60

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 5 (ASCL-5) and similar proteins; ASCL-5, also termed Class A basic helix-loop-helix protein 47 (bHLHa47), or achaete-scute homolog 5 (ASH-5), is an uncharacterized bHLH transcription factor that belongs to AS-C (achaete, scute, lethal of scute, and asense) family.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1034568349  86 KKANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19747     8 QKRNERERQRVKCVNEGYARLRDHLPGAMAEKRLSKVETLRAAIRYIKYLQDLL 61

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 2 (ASCL-2) and similar proteins; 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 a bHLH transcription factor that is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1034568349  87 KANDRERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19743     6 RRNERERNRVKLVNLGFAALRQHVPQGGASKKMSKVETLRSAVEYIRALQRLL 58

basic helix-loop-helix (bHLH) domain found in transcription factor 24 (TCF-24) and similar proteins; TCF-24 is an uncharacterized bHLH transcription factor that shows high sequence similarity with TCF-23.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1034568349  91 RERNRMHNLNSALDALRGVLPTFPDDAKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19710     8 RERSRVQTLRSAFLELQRTLPSVPPDTKLSKLDVLVLATTYIAHLMRTL 56

basic helix-loop-helix (bHLH) domain found in muscle-specific regulatory factor 4 (MRF4) and similar proteins; MRF4, also termed Class C basic helix-loop-helix protein 4 (bHLHc4), or myogenic factor 6 (Myf-6), is a bHLH transcription factor associated with myogenesis. It plays a role in skeletal muscle differentiation.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDaKLTKIETLRFAHNYIWALTQTLRIADH 144
Cdd:cd18934     2 RRKAATLRERRRLKKINEAFEALKRRTVPNPNQ-RLPKVEILRSAINYIEKLQDLLHSLDQ 61

basic helix-loop-helix (bHLH) domain found in myoblast determination protein 1 (MYOD1) and similar proteins; MYOD1, also termed Class C basic helix-loop-helix protein 1 (bHLHc1), or myogenic factor 3 (Myf-3), is a bHLH transcriptional activator that promotes transcription of muscle-specific target genes and plays a role in muscle differentiation. Together with Myf-5 and MYOG, MYOD1 co-occupies muscle-specific gene promoter core region during myogenesis.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDaKLTKIETLRFAHNYIWALTQTLR 140
Cdd:cd18936     6 RRKAATMRERRRLSKVNEAFETLKRCTSTNPNQ-RLPKVEILRNAIRYIESLQALLR 61

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster myogenic-determination protein (dMYOD) and similar proteins; dMYOD, also termed protein nautilus, or Myd, may play an important role in the early development of muscle in Drosophila.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1034568349  84 RRKKANDRERNRMHNLNSALDALRGVLPTFPDDaKLTKIETLRFAHNYIWALTQTL 139
Cdd:cd19699     2 RRKAATMRERRRLRKVNEAFEVLKRRTCPNPNQ-RLPKVEILRNAIEYIESLEDLL 56