[3H-Methyl]-methionine as possible methyl donor for formation of 5'-terminus of in vitro synthesized mRNA of cytoplasmic polyhedrosis virus of silkworm Bombyx mori.

The mRNA of the cytoplasmic polyhedrosis virus of silkworm Bombyx mori could be synthesized in vitro through the action of the virion associated RNA-polymerase in the presence of [3H-methyl]-methionine instead of S-adenosyl-L-methionine. The 3H-mRNA is isolated from the reaction mixture through a column of DEAE-Sephadex A-25 and digested with nuclease p1 and snake venom phosphodiesterase. The results of paper electrophoresis show that the methyl group of methionine is incorporated into the 5'-terminus of CPV mRNA. Even in the presence of S-adenosyl-L-methionine the [3H-methyl]-methionine could still function as a methyl donor for the formation of the 5'-caps of the mRNA of CPV.