Molecular cloning of cDNA for rat liver gap junction protein.

TLDR

An affinity‑purified antibody against the 27‑kD gap junction protein was used to screen a rat liver cDNA library in lambda gt11, yielding a 1,494‑bp clone encoding a 32,007‑Da protein. Immunocytochemistry localized the antigen to cytoplasmic surfaces of gap junctions, and the 1,494‑bp cDNA encodes a 32,007‑Da protein; Northern blotting showed that brain, kidney, and stomach express homologous mRNA, whereas heart and lens express smaller, less homologous transcripts.

Abstract

An affinity-purified antibody directed against the 27-kD protein associated with isolated rat liver gap junctions was produced. Light and electron microscopic immunocytochemistry showed that this antigen was localized specifically to the cytoplasmic surfaces of gap junctions. The antibody was used to select cDNA from a rat liver library in the expression vector lambda gt11. The largest cDNA selected contained 1,494 bp and coded for a protein with a calculated molecular mass of 32,007 daltons. Northern blot analysis indicated that brain, kidney, and stomach express an mRNA with similar size and homology to that expressed in liver, but that heart and lens express differently sized, less homologous mRNA.