Studies are to be carried out on the interaction of the transforming protein of Rous sarcoma virus, p60src, with polypeptides present in transformed cells. Polypeptide substrated and possible polypeptide inhibitors will be characterized. The viral protein or proteins encoded by each of the mRNAs of the avian coronavirus, infectious bronchitis virus, will be determined. The transcriptional mechanism which generated the subgenomic mRNAs of infectious bronchitis virus will be characterized.