STRUCTURE, CHROMOSOMAL LOCUS, AND PROMOTER OF MOUSE HES2 GENE, A HOMOLOG OF DROSOPHILA HAIRY AND ENHANCER OF SPLIT

Hes2 encodes a mammalian basic helix-loop-helix transcriptional repres sor homologous to the products of Drosophila hairy and Enhancer of spl it. Here, we isolated and characterized the mouse Hes2 gene. This gene consists of four exons, and all the introns are located within the pr otein-coding region at positions homologous to those of other Hes gene s. On the interspecific backcross analyses, mouse Hes2 is mapped to th e distal region of Chromosome 4 near the Hes3 and Hes5 loci, which are different from the Hes1 locus on Chromosome 16. Upstream of the trans cription initiation site, there are GC-rich regions, but a typical TAT A box is not present. Transient transfection analyses demonstrated tha t, while Hes1 and Hes5 promoter activities are significantly upregulat ed by the active form of Notch, a key regulator of cellular differenti ation, Hes2 and Hes3 promoter activities are not. These results sugges t that Hes genes are functionally classified into two groups: those th at are regulated by Notch and those that are not. (C) 1998 Academic Pr ess.