Diminished Sensitivity of Re‐initiation of Translation to Inhibition by Cap Analogues in Reticulocyte Lysates

Abstract
In a nuclease-treated [rabbit] reticulocyte lysate reinitiation of protein biosynthesis was less inhibited by 7-methylguanosine 5''-monophosphate (m7GMP), whereas primary-initiation could be totally blocked by cap analogues. A cap binding factor probably binds to mRNA as a 1st step in initiation of protein synthesis and this factor remains bound during the subsequent reinitiation cycles. Primarily because of the greater relative importance of the reinitiation process, globin synthesis in the untreated lysate was less inhibited by m7GMP.