Identification of a rat liver cDNA and mRNA coding for the 28 kDa gap junction protein

By screening of a rat liver cDNA library with complex and deoxyinosine containing oligonucleotide probes a cDNA clone was isolated and shown by sequencing to code for the amino-terminal half of the rat liver 28 kDa gap junction protein. The insert hybridized to a 1.9 kb species from rat and mouse liver poly(A)+ RNA in Northern blot analysis. In embryonic mouse hepatocytes the amount of the 1.9 kb mRNA increased 3-fold between 24 and 96 h in culture. This correlates with the previously described increase of the 28 kDa gap junction protein under these conditions.