Genetic and functional linkage of Kir5.1 and Kir2.1 channel subunits

We have identified several cDNAs for the human Kir5.1 subunit of inwardly r ectifying K+ channels, Alternative splicing of exon 3 and the usage of two alternative polyadenylation sites contribute to cDNA diversity. The hKir5.1 gene KCNJ16 is assigned to chromosomal region 17q23.1-24.2, and is separat ed by only 34 kb from the hKir2.1 gene (KCNJ2), In the brain, Kir5.1 mRNA i s restricted to the evolutionary older parts of the hindbrain, midbrain and diencephalon and overlaps a with Kir2.1 in the superior/inferior colliculu s and the pontine region. In the kidney Kir5.1 and Kir2.1 are colocalized i n the proximal tubule, When expressed in Xenopus oocytes, Kir5.1 is efficie ntly targeted to the cell surface and forms electrically silent channels to gether with Kir2.1, thus negatively controlling Kir2.1 channel activity in native cells. (C) 2001 Federation of European Biochemical Societies, Publis hed by Elsevier Science B.V. All rights reserved.