Novel polypeptides encoded by influenza virus subgenomic (DI type) virion RNAs

We have isolated a ts mutant of influenza A/FPV/Rostock/34 that induces the synthesis of a novel small polypeptide in infected cells. This polypeptide is encoded by a subgenomic virion RNA derived from RNA segment 3, apparently by internal deletion. A second polypeptide, similarly derived from RNA segment 1, was found only after in vitro translation of infected cell RNA. The subgenomic vRNAs we describe are probably similar to those found in influenza DI virus preparations. The possible role of 'subgenomic' polypeptides in DI virus-mediated interference is discussed.