Genomic structure and expression of human KCNJ9 (Kir3.3/GIRK3)

The human KCNJ9 (Kir 3.3, GIR-K3) is a member of the G-protein-activated in wardly rectifying potassium (GIRK) channel family. Here we describe the gen omic organization of the KCNJ9 locus on chromosome 1q21-23 as a candidate g ene for Type Il diabetes mellitus in the Pima Indian population. The gene s pans similar to 7.6 kb and contains one noncoding and two coding exons sepa rated by similar to 2.2 and similar to 2.6 kb introns, respectively. We ide ntified 14 single nucleotide polymorphisms (SNPs), including one that predi cts a Val366Ala substitution, and an 8 base-pair (bp) insertion/deletion. O ur expression studies revealed the presence of the transcript in various hu man tissues including pancreas, and two major insulin-responsive tissues: f at and skeletal muscle. The characterization of the KCNJ9 gene should facil itate further studies on the function of the KCNJ9 protein and allow evalua tion of the potential role of the locus in Type II diabetes. (C) 2000 Acade mic Press.