title: Polyoma virus complementary RNA directs the in vitro synthesis of capsid proteins VP1 and VP2.
abstract: Polyoma virus complementary RNA, synthesized in vitro by using highly purified Escherichia coli RNA polymerase and nondefective form I polyoma DNA, was translated in a wheat germ cell-free system. Polypeptides were synthesized that comigrated on sodium dodecyl sulfate-polyacrylamide gels with the polyoma capsid proteins VP1 and VP2, although most of the cell-free products were of smaller molecular weights. The VP1-size protein specifically immunoprecipitated with anti-polyoma virus serum, and upon digestion by trypsin yielded [35S]methionine-labeled tryptic peptides that co-chromatographed with the [3H]methionine-labeled tryptic peptides of virion-derived VP1 on both cation-exchange and anion-exchange resins. The VP2-size in vitro product contained all the virion VP2 methionine-labeled tryptic peptides, as shown by cation- and anion-exchange chromatography and two-dimensional fingerprinting on cellulose. We conclude that full-length polyoma VP1 and VP2 are synthesized in response to complementary RNA and consequently that the viral capsid proteins VP1, VP2, and VP3 are entirely virus coded.
mesh_terms: D002213:Capsid / Q000096:biosynthesis*; D002474:Cell-Free System; D002852:Chromatography, Ion Exchange; D004279:DNA, Viral / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D008970:Molecular Weight; D010452:Peptide Biosynthesis; D011120:Polyomavirus / Q000378:metabolism*; D014176:Protein Biosynthesis; D012367:RNA, Viral / Q000096:biosynthesis / Q000378:metabolism*; D014764:Viral Proteins / Q000096:biosynthesis*
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral; D014764:Viral Proteins; D012321:DNA-Directed RNA Polymerases