title: Competition between the Sendai virus N mRNA start site and the genome 3'-end promoter for viral RNA polymerase.
abstract: The genomic and antigenomic 3'-end replication promoters of Sendai virus are bipartite in nature and symmetrical, composed of le or tr sequences; a gene start or gene end site, respectively; and a simple hexameric repeat. The relative strengths of these 3'-end promoters determines the ratios of genomes and antigenomes formed during infection and whether model mini-genomes can be rescued from DNA by nondefective helper viruses. Using these tests of promoter strength, we have confirmed that tr is stronger than le in this respect. We have also found that the presence of a gene start site within either 3'-end promoter strongly reduces 3'-end promoter strength. The negative effects of the gene start site on the 3'-end promoter suggest that these closely spaced RNA start sites compete with each other for a common pool of viral RNA polymerase. The manner in which this competition could occur for polymerase off the template (in trans) and polymerase on the template (in cis) adds insight into how the viral RNA polymerase switches between its dual functions as transcriptase and replicase.
authors.affiliation: Department of Genetics and Microbiology, University of Geneva School of Medicine, CH1211 Geneva, Switzerland.
authors.forename: Philippe
authors.initials: P
authors.lastname: Le Mercier
authors.forename: Dominique
authors.initials: D
authors.lastname: Garcin
authors.forename: Eduardo
authors.initials: E
authors.lastname: Garcia
authors.forename: Daniel
authors.initials: D
authors.lastname: Kolakofsky
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D001667:Binding, Competitive; D002460:Cell Line; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D003673:Defective Viruses / Q000235:genetics / Q000502:physiology; D016679:Genome, Viral; D006378:Helper Viruses / Q000235:genetics / Q000502:physiology; D006801:Humans; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000737:chemistry / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics*; D011995:Recombination, Genetic; D029082:Sendai virus / Q000235:genetics* / Q000502:physiology*; D014758:Viral Core Proteins / Q000737:chemistry / Q000235:genetics*; D014779:Virus Replication
chemical_list: D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D012333:RNA, Messenger; D012367:RNA, Viral; D014758:Viral Core Proteins; D012321:DNA-Directed RNA Polymerases