Genetic economy of polyoma virus: capsid proteins are cleavage products of same viral gene.

Two-dimensional tryptic peptide maps of the nonhistone proteins of purified polyoma virus show marked similarities. Protein P(1) is a nondisaggregated, possibly covalent, dimer of the major capsid protein P(2), whereas P(3) and P(4) share several new peptides as well as many of the peptides derived from P(2). Extensive use of this kind of processing of viral proteins during the biosynthesis of DNA-containing animal viruses has not been reported previously.