Inhibition of vesicular stomatitis virus protein synthesis and infection by sequence-specific oligodeoxyribonucleoside methylphosphonates

Abstract

Oligodeoxyribonucleoside methylphosphates which have sequences complementary to the initiation codon regions of N, NS, and G vesicular stomatitis virus (VSV) mRNAs were tested for their ability to inhibit translation of VSV mRNA in a cell-free system and in VSV-infected mouse L cells. In a rabbit reticulocyte lysate cell-free system, the oligomers complementary to N (oligomer I) and NS (oligomer II) mRNAs inhibited translation of VSV N and NS mRNAs whereas oligomer III had only a slight inhibitory effect on N protein synthesis. At 100 and 150 .mu.M, oligomer I specifically inhibited N protein synthesis in the lysate. In contrast, at 150 .mu.M, oligomer II inhibited both N and NS protein synthesis. This reduced specificity of inhibition may be due to the formation of partial duplexes between oligomer II and VSV N mRNA. The oligomers had little or no inhibitory effects on the synthesis of globin mRNA in the same lysate system. Oligomers I-III specifically inhibited the synthesis of all five viral proteins in VSV-infected cells in a concentration-dependent manner. The oligomers had no effects on cellular protein synthesis in uninfected cells nor on cell growth. An oligothymidylate which forms only weak duplexes with poly(rA) had just a slight effect on VSV protein synthesis and yield of virus. Oligomers I-III have extensive partial complementarity with the coding regions of L mRNA. The nonspecific inhibition of viral protein synthesis in infected cells may reflect the role of N, NS, and/or L proteins in the replication and transcription of viral RNA or result from duplex formation between the oligomers and complementary, plus-strand viral RNA. The results of this study indicate that inhibition of viral protein synthesis in a cell-free lysate and in infected cells is primarily due to the interaction of oligomers I-III with complementary VSV mRNAs. Oligomers I-III also significantly inhibited VSV production in a manner corresponding to their effects on VSV protein synthesis. These results demonstrate that oligonucleoside methylphosphonates can be used to study viral gene expression and to control virus production.