The Sendai virus nonstructural C proteins specifically inhibit viral mRNA synthesis.
An in vitro transcription system for paramyxoviruses is described, in which polymerase-free templates are combined with cell extracts containing polymerase made in vivo via transfected plasmids. Both P and L are required for polymerase activity, and both must be coexpressed for optimum activity. mRNA synthesis here was found to be inversely proportional to the level of C expression, whereas defective interfering genome replication was largely unaffected by the level of C in the extract. The inhibition of transcription appeared to be due to the C' and C, but not the Y1 and Y2 proteins, and only occurred when C'/C was coexpressed with P and L. C'/C appears to intervene during polymerase formation, possibly by forming polymerase complexes which are inactive for transcription, but still competent for genome replication.
Curran
J
J
Department of Genetics and Microbiology, University of Geneva School of Medicine, Switzerland.
Marq
J B
JB
Kolakofsky
D
D
D001483:Base Sequence; D002478:Cells, Cultured; D015967:Gene Expression Regulation, Viral; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D010222:Parainfluenza Virus 1, Human / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D012367:RNA, Viral / Q000096:biosynthesis; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D012367:RNA, Viral; D014764:Viral Proteins; C051221:nonstructural C protein, Sendai virus