basic helix-loop-helix (bHLH) domain found in DNA-binding protein inhibitor ID1 and similar proteins; ID1, also termed Class B basic helix-loop-helix protein 24 (bHLHb24), or inhibitor of DNA binding 1, or inhibitor of differentiation 1, is a dominant negative helix-loop-helix (dnHLH) transcriptional regulator (lacking a basic DNA binding domain) which negatively regulates the bHLH transcription factors by forming heterodimers and inhibiting their DNA binding and transcriptional activity. ID1 interferes with centrosomal function. It has been implicated in the regulation of cell proliferation and differentiation in myogenesis, neurogenesis, and/or hematopoiesis.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 45383001  46 LLYDMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLALQ 91
Cdd:cd19691   4 LLYDMNGCYSRLKELVPTLPQNRKVSKVEILQHVIDYIWDLQVELD 49

basic helix-loop-helix (bHLH) domain found in DNA-binding protein inhibitor ID1 and similar proteins; ID1, also termed Class B basic helix-loop-helix protein 24 (bHLHb24), or inhibitor of DNA binding 1, or inhibitor of differentiation 1, is a dominant negative helix-loop-helix (dnHLH) transcriptional regulator (lacking a basic DNA binding domain) which negatively regulates the bHLH transcription factors by forming heterodimers and inhibiting their DNA binding and transcriptional activity. ID1 interferes with centrosomal function. It has been implicated in the regulation of cell proliferation and differentiation in myogenesis, neurogenesis, and/or hematopoiesis.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 45383001  46 LLYDMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLALQ 91
Cdd:cd19691   4 LLYDMNGCYSRLKELVPTLPQNRKVSKVEILQHVIDYIWDLQVELD 49

Helix-loop-helix DNA-binding domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|
gi 45383001    48 YDMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQ 87
Cdd:pfam00010  14 DRINDAFDELRELLPTLPPDKKLSKAEILRLAIEYIKHLQ 53

basic helix-loop-helix (bHLH) domain found in DNA-binding protein inhibitor ID1 and similar proteins; ID1, also termed Class B basic helix-loop-helix protein 24 (bHLHb24), or inhibitor of DNA binding 1, or inhibitor of differentiation 1, is a dominant negative helix-loop-helix (dnHLH) transcriptional regulator (lacking a basic DNA binding domain) which negatively regulates the bHLH transcription factors by forming heterodimers and inhibiting their DNA binding and transcriptional activity. ID1 interferes with centrosomal function. It has been implicated in the regulation of cell proliferation and differentiation in myogenesis, neurogenesis, and/or hematopoiesis.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 45383001  46 LLYDMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLALQ 91
Cdd:cd19691   4 LLYDMNGCYSRLKELVPTLPQNRKVSKVEILQHVIDYIWDLQVELD 49

basic helix-loop-helix (bHLH) domain found in DNA-binding protein inhibitor ID4 and similar proteins; ID4, also termed Class B basic helix-loop-helix protein 27 (bHLHb27), or inhibitor of DNA binding 4, or inhibitor of differentiation 4, is a dominant negative helix-loop-helix (dnHLH) transcriptional regulator (lacking a basic DNA binding domain) which negatively regulates the bHLH transcription factors by forming heterodimers and inhibiting their DNA binding and transcriptional activity. It plays a role in adipose cell differentiation.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 45383001  46 LLYDMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLALQ 91
Cdd:cd19694   7 LQYDMNDCYSRLKRLVPTIPPNKKVSKVEILQHVIDYILDLQLALE 52

basic helix-loop-helix (bHLH) domain found in DNA-binding protein inhibitor ID3 and similar proteins; ID3, also termed Class B basic helix-loop-helix protein 25 (bHLHb25), or helix-loop-helix protein HEIR-1, or ID-like protein inhibitor HLH 1R21, or inhibitor of DNA binding 3, or inhibitor of differentiation 3, is a dominant negative helix-loop-helix (dnHLH) transcriptional regulator (lacking a basic DNA binding domain) which negatively regulates the bHLH transcription factors by forming heterodimers and inhibiting their DNA binding and transcriptional activity. It negatively regulates muscle differentiation by inhibiting the DNA-binding activities of the myogenic regulatory factors.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....
gi 45383001  46 LLYDMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLA 89
Cdd:cd19693  18 LLYDMNDCYSRLRELVPGVPQGTKLSQVEILQHVIDYILDLQIV 61

helix loop helix domain;

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|...
gi 45383001     49 DMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLALQ 91
Cdd:smart00353  10 KINEAFDELRSLLPTLPKNKKLSKAEILRLAIEYIKSLQEELQ 52

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
                ....*....|....*....|....*....|....*...
gi 45383001  50 MKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQ 87
Cdd:cd00083   8 INDAFEELKRLLPELPDSKKLSKASILQKAVEYIRELQ 45

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
                ....*....|....*....|....*....|....*...
gi 45383001  54 YSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLALQ 91
Cdd:cd11422  19 FSKLRRIVPLIPRDRKPSKVDTLKGATEYIRLLQRILE 56

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
                ....*....|....*....|....*....|....*
gi 45383001  56 RLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLAL 90
Cdd:cd11390  21 ALRKVLPTVPPDKKLSKIETLRLAINYIAALSDLL 55

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster helix loop helix protein 3B (dHLH3B) and similar proteins; Drosophila HLH3B is an uncharacterized bHLH transcription factor that belongs to the T-cell acute lymphocytic leukemia protein/ lymphoblastic leukemia-derived sequence (TAL/LYL) family.

                        10        20        30
                ....*....|....*....|....*....|....*
gi 45383001  49 DMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYI 83
Cdd:cd19708  15 NVNGAFAELRKLVPTHPPDKKLSKNEILRLAIKYI 49

basic helix-loop-helix (bHLH) domain found in achaete-scute-like proteins, ASCL3-5, and similar proteins; This subfamily includes three ASCL family of transcription factors, ASCL-3, ASCL-4 and ASCL-5. 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 specifically localized in the duct cells of the salivary glands. It may act as transcriptional repressor that inhibits myogenesis. ASCL-4, also termed Class A basic helix-loop-helix protein 44 (bHLHa44), or achaete-scute homolog 4 (ASH-4), or Hash4, may be involved in skin development. 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 is close related to ASCL-3 and ASCL-4.

                        10        20        30
                ....*....|....*....|....*....|....
gi 45383001  54 YSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQ 87
Cdd:cd19724  20 YARLRRHLPLENKDKRLSKVETLRAAIRYIKHLQ 53

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
                ....*....|....*....|....*....|....*....|....*
gi 45383001  47 LYDMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLALQ 91
Cdd:cd19717  22 MHNLNAALDSLREVLPTFPEDAKLTKIETLRFAHNYIWALSETLR 66

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
                ....*....|....*....|....*....|
gi 45383001  57 LRALVPTLPRHRRVSKVELLQHVIDYIWDL 86
Cdd:cd19686  23 LRRHIPTFPYEKRLSKVDTLRLAIQYINFL 52

basic helix-loop-helix (bHLH) domain found in neurogenin-3 (NGN-3) and similar proteins; NGN-3, also termed Class A basic helix-loop-helix protein 7 (bHLHa7), or protein atonal homolog 5 (ATOH5), is a neural-specific bHLH transcription factor expressed in the developing central nervous system and the embryonic pancreas. It is involved in neurogenesis and plays an important role in spermatogenesis.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*
gi 45383001  47 LYDMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLALQ 91
Cdd:cd19718  20 MHNLNSALDALRSVLPTFPDDAKLTKIETLRFAHNYIWALTETLR 64

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 4 (ASCL-4) and similar proteins; ASCL-4, also termed Class A basic helix-loop-helix protein 44 (bHLHa44), or achaete-scute homolog 4 (ASH-4), or Hash4, is a bHLH transcriptional regulator that may be involved in skin development.

                        10        20        30
                ....*....|....*....|....*....|....
gi 45383001  54 YSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQ 87
Cdd:cd19746  27 YARLREHLPQELADKRLSKVETLRAAIDYIKHLQ 60

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
                ....*....|....*....|....*....|
gi 45383001  54 YSRLRALVPTLPRHRRVSKVELLQHVIDYI 83
Cdd:cd19701  35 FAELRKLLPTLPPDKKLSKIEILRLAICYI 64

basic helix-loop-helix (bHLH) domain found in T-cell acute lymphocytic leukemia protein 1 (TAL-1) and similar proteins; 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-1 has been implicated in T-cell acute lymphoblastic leukemia. In common with other tissue-specific bHLH proteins, Tal heterodimerizes with ubiquitously-expressed members of the E2A family and form a DNA-binding complex with an E-box (CANNTG) to regulate transcription at its recognition site.

                        10        20        30
                ....*....|....*....|....*....|....*
gi 45383001  49 DMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYI 83
Cdd:cd19706  18 NVNGAFAELRKLIPTHPPDKKLSKNEILRLAMKYI 52

basic helix-loop-helix (bHLH) domain found in Arabidopsis thaliana phytochrome interacting factors (PIFs) and similar proteins; The family includes several bHLH transcription factors from Arabidopsis thaliana, such as PIFs, ALC, PIL1, SPATULA, and UNE10. PIFs (PIF1, PIF3, PIF4, PIF5, PIF6 and PIF7) have been shown to control light-regulated gene expression. They directly bind to the photoactivated phytochromes and are degraded in response to light signals. ALC, also termed AtbHLH73, or protein ALCATRAZ, or EN 98, is required for the dehiscence of fruit, especially for the separation of the valve cells from the replum. It promotes the differentiation of a strip of labile non-lignified cells sandwiched between layers of lignified cells. PIL1, also termed AtbHLH124, or protein phytochrome interacting factor 3-like 1, or EN 110, is involved in responses to transient and long-term shade. It is required for the light-mediated inhibition of hypocotyl elongation and necessary for rapid light-induced expression of the photomorphogenesis- and circadian-related gene APRR9. PIL1 seems to play a role in multiple PHYB responses, such as flowering transition and petiole elongation. SPATULA, also termed AtbHLH24, or EN 99, plays a role in floral organogenesis. It promotes the growth of carpel margins and of pollen tract tissues derived from them. UNE10, also termed AtbHLH16, or protein UNFERTILIZED EMBRYO SAC 10, or EN 99, is required during the fertilization of ovules by pollen.

                        10        20        30
                ....*....|....*....|....*....|....*.
gi 45383001  56 RLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLALQ 91
Cdd:cd11445  20 KMKALQELIPNCNKTDKASMLDEAIEYLKSLQLQVQ 55

basic helix-loop-helix (bHLH) domain found in protein atonal homologs ATOH1, ATOH7 and similar proteins; The family includes ATOH1 and ATOH7. 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). 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. The family also includes protein Amos (also termed absent MD neurons and olfactory sensilla protein, or reduced olfactory organs protein, or rough eye protein). It is a bHLH transcription factor that promotes multiple dendritic neuron formation in the Drosophila peripheral nervous system.

                        10        20        30
                ....*....|....*....|....*....|....
gi 45383001  54 YSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQ 87
Cdd:cd11430  20 FDQLRSVVPSIGNDKKLSKYETLQMAQIYIETLS 53

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
                ....*....|....*....|....*....|....*....|....*
gi 45383001  47 LYDMKGCYSRLRALVPTLPRHRRVSKVELLQHVIDYIWDLQLALQ 91
Cdd:cd19720  47 MHDLNSALDNLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEILR 91