Localization of N6-methyladenosine in the Rous sarcoma virus genome

Abstract

The 10,000-nucleotide RNA genome of the Prague strain, subgroup B (PR-B) of Rous sarcoma virus, was found to contain 11.6 ± 0.5 residues of m 6Ap by quantitative analysis of 32P-labeled virion RNA after complete RNAase digestion. Approximately ten of the m 6Ap residues are located, without obvious clustering, in that region of the genome between 500 and 4000 nucleotides from the 3′ poly(A) end. The src gene, which is required for transformation, and part of the env gene, which codes for the major viral envelope glycoprotein, have previously been mapped in this region of the viral genome. A transformation-defective deletion mutant of PR-B Rous sarcoma virus, which lacks the src gene, has 7.0 ± 0.2 m 6Ap residues per RNA subunit. This supports our mapping of a portion of the m 6A residues in src and suggests that this methylation is specific to certain regions of the genome. The possible significance of this result for Rous sarcoma virus RNA processing and translation is discussed.