Molecular characterization and nephron distribution of a family of transcripts encoding the pore-forming subunit of Ca2+ channels in the kidney.

摘要: Abstract Active, transepithelial, Ca2+ reabsorption in kidney occurs primarily the distal convoluted tubule. Recent evidence suggests that entry of at apical membrane through channels bearing resemblance to those voltage-dependent L type may be rate-determining step reabsorption. To determine molecular identity pore-forming subunit channel(s) kidney, a homology-based PCR cloning strategy was employed. Nondegenerate primers, based on conserved regions published cDNA sequences channel alpha 1 subunits, were used amplify from rat and products subcloned sequenced. A family species identified, representing alternatively spliced transcripts four known genes encoding these subunits. Northern blot analysis indicated expression each exhibits distinct spatial distribution within kidney. One gene, CaCh4, is expressed cortex, by microdissected-tubule found predominantly tubule, consistent with role transepithelial this site.