Characterization of the human HTF4 gene
Abstract
The human HTF4 gene encodes a transcription factor defined as basic helix-loop-helix (bHLH) proteins of class A. This class of transcription factors shares a conserved DNA-binding domain, a helix-loop-helix motif, that mediates dimerization both with itself or with other HLH proteins. Dimers of bHLH interact with a consensus sequence, CANNTG, known as the E box, which is found in the regulatory regions of various tissue specific genes including immunoglobulin genes, muscle-specific genes, neuronal genes, and pancreatic genes. HTF4 has been implicated in several developmental processes including myogenesis, neurogenesis and the development of B cells and T cells. To learn about the genomic organization of the HTF4 gene, bacterial artificial chromosomes containing genomic DNA were characterized. The results show that the HTF4 gene is relatively large. Based on comparative studies, the results identified 21 exons dispersed in genomic sequence. The largest exon is 1993 nucleotides long, defining the 3′ untranslated region of the gene. The protein-encoding exons range from 56 to 232 nucleotides. Comparison of HTF4a, a transcript encoded by the gene, to that for related proteins suggests that alternative splicing may contribute to protein diversity through utilization of alternative exons and/or alternative splice sites during mRNA processing. A segment of sequence representing an alternative exon was identified in the HTF4 gene. This segment was not found in HTF4a cDNA, but has been identified in mouse, chicken and rat homologs. Another isoform, termed HTF4b/HEB is probably produced by utilization of an alternative splice site in the 5′ untranslated region of the mRNA primary transcripts. Furthermore, many alternative/cryptic splice sites were found throughout the genomic sequence and utilization of these alternative splice sites appears to be consistent with production of multiple protein isoforms.
Degree
Ph.D.
Advisors
Bina, Purdue University.
Subject Area
Biochemistry
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