The in vitro soluble RNA methylase activity of SV40-induced hamster tumors.

Abstract

Summary The in vitro methylase activity of SV40-induced hamster tumors and normal hamster tissues has been studied. Extracts of normal hamster tissues such as connective tissue, liver, thymus, and skeletal muscle are capable of hypermethylating yeast soluble RNA (sRNA) in the N 1 position of guanosine and possibly of adenosine. Extracts of SV40-induced tumors are capable of hypermethylating yeast sRNA more extensively. Incorporation of radioactive methyl- 14 C groups was found in N 1 -methylguanosine, N 1 , N 1 -dimethylguanosine, N 6 -methyladenine, and 5methyluridine. SV40 tumor extracts are capable of hypermethylating homologous sRNA extracted from normal hamster liver while extracts of normal tissues cannot. Significant incorporation of methyl- 14 C groups was found in the N 1 -methylguanosine of hamster sRNA hydrolysates.