Isolation and characterization of xenopus laevis albumin mRNA.

The messenger RNA for albumin was isolated from the liver of male frogs. Purification was achieved using oligo(dT)-cellulose chromatography and sucrose gradient centrifugation under denaturing conditions. As judged by translational activity in a cell-free protein-synthesizing system derived from rabbit reticulocytes, albumin mRNA was enriched 259-fold as compared to the total ribonucleic acid of the liver cells. Purified albumin mRNA migrated after sucrose gradient centrifugation as a single symmetrical peak of approximately 17 S and also moved as a single band following denaturing agarose gel electrophoresis. Albumin mRNA possess properties compatible with the presence of a poly(adenylic acid) sequence. Translation in vitro yielded a product which is immunoprecipitable with anti-(frog albumin) and which showed a single radioactive peak having a molecular weight of about 74000 in sodium dodecylsulfate/polyacrylamide gel electrophoresis. Complementary DNA was synthesized using reverse transcriptase, and, as a template, purified albumin mRNA. Following hybridization under conditions of excess RNA, the rot1/2 of albumin mRNA was found to be 1.8 X 10-3 mol . s . 1-1. This result also confirmed that albumin nRNA had been isolated in a highly purified form.