Blocked and Unblocked 5′ Termini in Reovirus Genome RNA

Abstract

Uniformly 32 P-labeled, double-stranded genome RNA isolated from purified reovirus contains two types of 5′-terminal sequences. One strand contains a phosphatase-resistant 5′-terminal structure, XpppG * pCpU, which is also present in the viral mRNA. The 5′ blocking group, X, is removed by β-elimination indicating that it is a nucleoside containing free 2′,3′-hydroxyls. G * pC is an alkaline-resistant, 2′- O -methylated sequence. The other strand contains a phosphatase-sensitive 5′ sequence, ppGpPupPyp. The results are discussed in relation to blocked 5′-terminal structures in other viral and cellular RNAs.