title: Synthesis and methyltransferase activity of nonstructural protein nsP1 in Sindbis virus-infected Aedes albopictus cells.
abstract: To investigate the synthesis and turnover of the nonstructure protein, nsP1, in Aedes albopictus cells, we labeled infected cells with [35S]-methionine and immunoprecipitated nsP1 with a polyclonal monospecific rabbit antibody. Synthesis of nsP1 in mosquito cells could be detected 2 hr after infection and continued as long as 24 hr post-infection, regardless whether the infected cells were maintained at 28 degrees C , 34.5 degrees C , or 37 degrees C. Whereas the time pattern of nsP1 synthesis varied with temperature. Nonstructural protein 1 synthesis at 28 degrees C was maximal at 4 hr, then decreased. At 37 degrees C synthesis reached a high level at 2 hr and remained constant for 24 hr. Pulse-chase experiments showed that nsP1 in mosquito cells, whether made as early as 5 hr post-infection or as late as 24 hr, were stable during that time, the longest period tested. Enzyme activity reached a maximum at 10 hr and remained almost the same level until 24 hr. The yield of Sindbis virus from mosquito cells was higher at 34.5 degrees C and 37 degrees C than at 28 degrees C. Methyltransferase activity was needed for modification of positive-strand genomic and subgenomic RNAs. The activity of methyltransferase observed until late in the replication cycle probably accounted for both the continued synthesis and minimal turnover of nsP1.
authors.affiliation: Department of Medical Technology, Fooyin Institute of Technology, Kaohsiung, Taiwan, ROC.
authors.forename: H L
authors.initials: HL
authors.lastname: Wang
authors.forename: V
authors.initials: V
authors.lastname: Stollar
mesh_terms: D000330:Aedes / Q000821:virology*; D000818:Animals; D002478:Cells, Cultured; D012845:Sindbis Virus / Q000502:physiology*; D013696:Temperature; D017361:Viral Nonstructural Proteins / Q000096:biosynthesis*; D014779:Virus Replication; D012359:tRNA Methyltransferases / Q000378:metabolism*
chemical_list: D017361:Viral Nonstructural Proteins; C104211:nsP1 protein, Sindbis virus; D012359:tRNA Methyltransferases