Antisense oligodeoxynucleotides provide insight into mechanism of translation initiation of two Sendai virus mRNAs.

Translation of Sendai virus nucleocapsid protein (NP) and phosphoprotein (P/C) mRNAs in rabbit reticulocyte lysates in the presence of antisense oligodeoxynucleotides (15-20-mers) showed that oligonucleotides having complementarity within the 5' noncoding region of the mRNAs blocked translation, oligonucleotides having complementarity within 20 nucleotides upstream from the initiator codon blocked translation only partially, and oligonucleotides complementary to the coding region of mRNA had no effect on translation. The results suggest the possibility that the 80 S initiation complex may form about 20 bases upstream from the initiator codon. Alternatively, the 40 S preinitiation complex may recognize an initiator codon at least 20 nucleotides upstream from the codon, activating a helix-destabilizing process.