Evidence for role of m7G5'-phosphate group in recognition of eukaryotic mRNA by initiation factor IF-M3.

7-methylguanosine 5'-monophosphate inhibits protein synthesis in a fractionated, messenger-dependent, reticulocyte cell-free system. This compound also inhibits binding of histone mRNA to reticulocyte ribosomes as well as interaction of VSV mRNA and histone mRNA but not EMC virus RNA with purified initiation factor IF-M3. These studies provide evidence that the role of 7-methylguanosine in the mechanism for initiation of eukaryotic mRNA translation may be related to specific recognition of mRNA by initiation factor IF-M3.