ISOLATION, CHARACTERIZATION, AND CHROMOSOMAL MAPPING OF THE HUMAN NKX6.1 GENE (NKX6A), A NEW PANCREATIC-ISLET HOMEOBOX GENE

Nkx6.1 (gene symbol MKX6A), a new member of the NK homeobox gene famil y, was recently identified in rodent pancreatic islet beta-cell lines. The pattern of expression suggested that this gene product might be i mportant for control of islet development and/or regulation of insulin biosynthesis. We now report cloning of human NKX6A, characterization of its genomic structure, and its chromosomal localization. The predic ted protein of human NKX6A contained 367 amino acids and had 97% ident ity to the hamster protein. The highly conserved NK decapeptide and ho meodomain regions were identical between human and hamster, suggesting functional importance of these domains. The coding region spanned app roximately 4.8 kb and was composed of three exons. The gene was locali zed to four CEPH ''B'' yeast artificial chromosome clones (914B4, 951G 9, 981D6, and 847B3), and a nearby polymorphic marker (D4S1538) on chr omosome 4 was identified <1270 kb from the gene. Using fluorescence in situ hybridization, we also determined that NKX6A maps to 4q21.2-q22. (C) 1997 Academic Press.