title: Mechanism of RNA synthesis initiation by the vesicular stomatitis virus polymerase.
abstract: The minimal RNA synthesis machinery of non-segmented negative-strand RNA viruses comprises a genomic RNA encased within a nucleocapsid protein (N-RNA), and associated with the RNA-dependent RNA polymerase (RdRP). The RdRP is contained within a viral large (L) protein, which associates with N-RNA through a phosphoprotein (P). Here, we define that vesicular stomatitis virus L initiates synthesis via a de-novo mechanism that does not require N or P, but depends on a high concentration of the first two nucleotides and specific template requirements. Purified L copies a template devoid of N, and P stimulates L initiation and processivity. Full processivity of the polymerase requires the template-associated N protein. This work provides new mechanistic insights into the workings of a minimal RNA synthesis machine shared by a broad group of important human, animal and plant pathogens, and defines a mechanism by which specific inhibitors of RNA synthesis function.
authors.affiliation: Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Morin
authors.forename: Amal A
authors.initials: AA
authors.lastname: Rahmeh
authors.forename: Sean P J
authors.initials: SP
authors.lastname: Whelan
mesh_terms: D012321:DNA-Directed RNA Polymerases / Q000302:isolation & purification / Q000378:metabolism*; D008954:Models, Biological; D012367:RNA, Viral / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D018116:Vesiculovirus / Q000201:enzymology*; D014764:Viral Proteins / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D012367:RNA, Viral; D011994:Recombinant Proteins; D014764:Viral Proteins; D012321:DNA-Directed RNA Polymerases