RNA EDITING IN NEWCASTLE-DISEASE VIRUS

The co-transcriptional editing of the Newcastle disease virus (NDV) P gene has been studied by sequence analysis of cloned viral genomic RNA and mRNA. Evidence has been obtained for the specific insertion of non-templated G nucleotides, the consequence of which is the generation of three populations of P gene-derived mRNAs. The three populations encode proteins (P, V and W) which have a common N-terminal region, but which utilize three different reading frames at their C termini. Paradoxically, NDV edits its P gene mRNA by the insertion of non-templated G residues in a manner similar to Sendai and measles viruses (P --> V editing) despite its apparent closer evolutionary relationship to the simian virus type 5, mumps and related group of viruses which edit a V genomic sequence to generate an mRNA to encode a functional P protein (V --> P editing).