Alternative titles; symbols
HGNC Approved Gene Symbol: NHLH1
Cytogenetic location: 1q23.2 Genomic coordinates (GRCh38): 1:160,367,071-160,372,846 (from NCBI)
NHLH1 encodes a member of the helix-loop-helix (HLH) family of transcription factors and is expressed in the developing nervous system (Begley et al., 1992).
Begley et al. (1992) identified a novel member of the HLH family based on its hybridization to SCL (TAL1; 187040). SCL had been identified because of its involvement in a 1;14 translocation in a stem cell leukemia; it is disrupted in about one-fourth of cases of T-cell acute lymphoblastic leukemia. The novel gene was referred to as NSCL because of its expression in the developing nervous system. Murine Nscl cDNA clones had a coding region of 399 basepairs, predicting a protein of 14.8 kD. The nucleotide sequence showed 71% identity and the amino acid sequence 61% identity to murine Scl in the HLH domain.
In the course of attempting to isolate the murine homolog of TAL1, Brown et al. (1992) identified a distinct basic helix-loop-helix (bHLH) gene, which they designated Hen1. They isolated the human equivalent of Hen1. Brown et al. (1992) showed that HEN1 and a highly related protein, HEN2 (NHLH2; 162361), of 133 and 135 residues, respectively, are coexpressed in a human neuroblastoma cell line. The 2 proteins share 98% amino acid identity in their bHLH domains. Brown et al. (1992) concluded that the HEN1 and HEN2 genes may serve important regulatory functions in the developing nervous system.
By mammalian 2-hybrid analysis, Manetopoulos et al. (2003) showed that HEN1 interacted with both LMO2 (180385) and LMO4 (603129). LMO4, but not LMO2, could augment HEN1-mediated repression of E47 (147141) transcriptional activity. LMO4 could also prevent HEN1-mediated neurite extension in rat hippocampal precursor cells. Manetopoulos et al. (2003) concluded that LMO4 can modulate the transcriptional activity of HEN1.
Begley et al. (1992) mapped the Nscl gene to murine chromosome 1 by study of recombinant inbred strains. It was closely linked to the serum amyloid P locus (Sap; see 104770) on distal chromosome 1; no recombinants were found out of 51 opportunities. Since the human SAP gene is located at 1q21-q23, the human equivalent of the mouse gene is presumably located there also.
By a combination of somatic cell hybridization and in situ hybridization, Brown et al. (1992) mapped the human HEN1 gene to chromosome 1q22. By fluorescence in situ hybridization, Lipkowitz et al. (1992) mapped the NSCL1 gene to 1q21.
Mullick et al. (1995), who symbolized the mouse gene as Nhlh1, showed that the gene is closely linked to the mouse looptail (Lp) mutation on chromosome 1.
Cogliati et al. (2002) developed Nhlh1 null mice. Homozygous mutant mice were predisposed to premature, adult-onset, unexpected death. Electrocardiograms revealed decreased heart rate variability, stress-induced arrhythmia, and impaired baroreceptor sensitivity. Heterozygosity for the closely related transcription factor Nhlh2 increased the severity of the Nhlh1 null phenotype. No signs of primary cardiac structural or conduction abnormalities were revealed in the Nhlh1 null mice. The pattern of altered heart rhythm observed in basal and experimental stress conditions suggested that a deficient parasympathetic tone contributed to the arrhythmia in the Nhlh1 null mice. Supporting their conclusion, Cogliati et al. (2002) found that Nhlh1 was expressed in the developing brainstem and vagal nuclei of wildtype mice.
Begley, C. G., Lipkowitz, S., Gobel, V., Mahon, K. A., Bertness, V., Green, A. R., Gough, N. M., Kirsch, I. R. Molecular characterization of NSCL, a gene encoding a helix-loop-helix protein expressed in the developing nervous system. Proc. Nat. Acad. Sci. 89: 38-42, 1992. [PubMed: 1729708] [Full Text: https://doi.org/10.1073/pnas.89.1.38]
Brown, L., Espinosa, R., III, Le Beau, M. M., Siciliano, M. J., Baer, R. HEN1 and HEN2: a subgroup of basic helix-loop-helix genes that are coexpressed in a human neuroblastoma. Proc. Nat. Acad. Sci. 89: 8492-8496, 1992. [PubMed: 1528853] [Full Text: https://doi.org/10.1073/pnas.89.18.8492]
Cogliati, T., Good, D. J., Haigney, M., Delgado-Romero, P., Eckhaus, M. A., Koch, W. J., Kirsch, I. R. Predisposition to arrhythmia and autonomic dysfunction in Nhlh1-deficient mice. Molec. Cell. Biol. 22: 4977-4983, 2002. [PubMed: 12077327] [Full Text: https://doi.org/10.1128/MCB.22.14.4977-4983.2002]
Lipkowitz, S., Gobel, V., Varterasian, M. L., Nakahara, K., Tchorz, K., Kirsch, I. R. A comparative structural characterization of the human NSCL-1 and NSCL-2 genes: two basic helix-loop-helix genes expressed in the developing nervous system. J. Biol. Chem. 267: 21065-21071, 1992. [PubMed: 1328219]
Manetopoulos, C., Hansson, A., Karlsson, J., Jonsson, J.-I., Axelson, H. The Lim-only protein LMO4 modulates the transcriptional activity of HEN1. Biochem. Biophys. Res. Commun. 307: 891-899, 2003. [PubMed: 12878195] [Full Text: https://doi.org/10.1016/s0006-291x(03)01298-1]
Mullick, A., Groulx, N., Trasler, D., Gros, P. Nhlh1, a basic helix-loop-helix transcription factor, is very tightly linked to the mouse looptail (Lp) mutation. Mammalian Genome 6: 700-704, 1995. [PubMed: 8563167] [Full Text: https://doi.org/10.1007/BF00354291]