Identification of the major polyadenylylated transcription products and the genes active in their synthesis in a rat insulinoma.

Three RNA fractions with molecular weights of 200,000, 280,000, and 360,000, have been identified as the major polyadenylylated transcription products in a transplantable rat pancreatic islet cell tumor that synthesizes insulin. These three RNAs share sequence homology as demonstrated by comparisons of both partial and complete RNase T1 digestion products. The 200,000 and 280,000 molecular weight species hybridize primarily with three EcoRI restriction fragments of the rat genome having molecular weights of 1.4 X 10(6), 1.6 X 10(6), and 6.0 X 10(6). The 360,000 molecular weight species hybridizes preferentially with the 6.0 X 10(6) molecular weight DNA fragment.