Effects of methionine deprivation of Newcastle disease virus in chicken embryo cells
Krauter, K.M.; Consigli, R.A.
American Journal of Veterinary Research 35(7): 985-995
1974
ISSN/ISBN: 0002-9645 PMID: 4601937 Document Number: 79313
Each of the individual amino acids in Eagle's minimal essential medium (MEM) was needed in the synthesis of NDV in chick embryo cells; however, methionine was needed to the greatest extent. Early recovery of viral synthesis upon addition of methionine to a methionine-deprived NDV infection indicated that methionine deprivation possibly inhibited a late step of viral synthesis. Absence of methionine did not inhibit viral RNA synthesis, but did inhibit plaque-forming activity approximately 96% during the same period. Methionine deprivation did not affect the number of cells synthesizing structural antigens (immunofluorescence); however, haemagglutinin production was reduced by 50%. Methionine was also found to be essential in methylation, since alpha-methyl-methionine (methionine analogue) was found to substitute for methionine late in infection (after 5 hours) and allowed synthesis of viral progeny. In addition, the methyl groups from isotopically labelled methionine were detected in RNA isolated from purified virions of NDV. These findings indicate that methionine is essential for synthesis of NDV in chick embryo cells, since methionine is required for viral protein synthesis, methylation, and maturation of the virion.