Sequence arrangement of the 5' ends of simian virus 40 16S and 19S mRNAs.

Electron microscopic examination of molecular hybrids between simian virus 40 DNA, that had been cleaved with EcoRI and then digested with exonuclease III, and either 16S or 19S mRNA produced late during the viral infection cycle indicated that each of these mRNAs contained a 5'-terminal "leader" sequence that was encoded in the viral genome at about map position 0.71-0.75. Hybridization of each of these mRNAs to viral DNA immobilized on nitrocellulose filters supported the electron microscopic observations.