Curran J Marq JB Kolakofsky D 1992 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. https://sonar.ch/global/documents/195612 eng info:eu-repo/semantics/altIdentifier/doi/10.1016/0042-6822(92)90588-g info:eu-repo/semantics/altIdentifier/pmid/1322593 Virology. - 1992 Base Sequence Cells, Cultured Gene Expression Regulation, Viral In Vitro Techniques Molecular Sequence Data Mutagenesis, Site-Directed Oligodeoxyribonucleotides Parainfluenza Virus 1, Human RNA, Messenger RNA, Viral Transcription, Genetic Viral Proteins The Sendai virus nonstructural C proteins specifically inhibit viral mRNA synthesis. http://purl.org/coar/resource_type/c_6501