Temperature-sensitive mutants of influenza virus: a mutation in the hemagglutinin gene.

Abstract

Abstract A mutant (ts-61S) belonging to a single recombination-complementation group (Group VI) was obtained by segregation of an influenza virus WSN (HON1) temperature-sensitive double mutant (ts-61) that possessed mutational lesions characteristic of Groups V and VI. The segregant retained the thermolabile hemagglutinating activity of the parental mutant, ts-61, but lost the defectiveness in virion RNA synthesis manifested by the parent at the nonpermissive temperature. No hemagglutinating activity developed in cells infected with ts-61S at the nonpermissive temperature. In rescue experiments all HO-serotype progeny from the cross between ts-61S (HO-serotype) and temperature-resistant H3-serotype virus were temperature-sensitive, localizing the ts defect in the hemagglutinin gene. No glycosylated hemagglutinin polypeptide was detected in the polyacrylamide gel electropherogram of cells infected with ts-61S at the nonpermissive temperature, whereas the synthesis of neuraminidase (the other virion glycoprotein) proceeded normally at both permissive and nonpermissive temperatures. The results indicate that the Group VI mutation is in the gene coding for the viral hemagglutinin.