RT Journal Article SR Electronic(1) A1 Harper, D. R. A1 Samson, A. C. R. A1 Lee, C. M. A1 Simon, E.YR 1983 T1 A Temperature-sensitive Mutant of Newcastle Disease Virus which is Affected in Both haemagglutinin—neuraminidase and Matrix Proteins JF Journal of General Virology, VO 64 IS 12 SP 2781 OP 2784 DO https://doi.org/10.1099/0022-1317-64-12-2781 PB Microbiology Society, SN 1465-2099, AB SUMMARY Virions prepared from a non-revertible temperature-sensitive (ts) mutant (ts53) of Newcastle disease virus (NDV) grown in ovo at the permissive temperature (34 °C) possessed thermolabile haemagglutination and neuraminidase activities compared with parental (ts +) virions. Purified haemagglutinin—neuraminidase (HN) protein from ts53 virions was also more thermolabile than ts + HN protein. SDS-PAGE analysis of [3H]leucine pulse- and pulse/chase-labelled NDV proteins synthesized in chick embryo fibroblasts following infection with ts + and ts53 virus revealed that ts53 matrix (M) protein was unstable and disappeared during chase incubations only at the non-permissive temperature (42 °C). The non-revertibility of the ts53 mutant may indicate that it is a double mutant affected in both HN and M genes; alternatively this mutant may only be affected in the HN gene, the close physical association of the thermolabile HN with the M protein during virus maturation resulting in the lack of protection of the M protein from the action of cellular proteases at the non-permissive temperature., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-64-12-2781