Critical phosphoprotein elements that regulate polymerase architecture and function in vesicular stomatitis virus.
The RNA-dependent RNA polymerase (RdRP) of nonsegmented negative-sense RNA viruses consists of a large catalytic protein (L) and a phosphoprotein cofactor (P). During infection, the RdRP replicates and transcribes the viral genome, which resides inside an oligomer of nucleocapsid protein (N-RNA). The classical view of P as a cofactor for L assigns a primary role of P as a bridge mediating the access of L to the RNA template, whereby its N-terminal domain (P(NTD)) binds L and its C-terminal domain (P(CTD)) binds N-RNA. Recent biochemical and structural studies of a prototype nonsegmented negative-sense RNA virus, vesicular stomatitis virus, suggest a role for P beyond that of a mere physical link: P induces a structural rearrangement in L and stimulates polymerase processivity. In this study, we investigated the critical requirements within P mediating the functional interaction with L to form a fully functional RdRP. We analyzed the correlation between the impact of P on the conformation of L and its activity in RNA synthesis and the consequences of these events on RdRP function. We identified three separable elements of the P(NTD) that are required for inducing the conformational rearrangement of L, stimulating polymerase processivity, and mediating transcription of the N-RNA. The functional interplay between these elements provides insight into the role of P as a dynamic player in the RNA synthesis machine, influencing essential aspects of polymerase structure and function.
Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA.
Amal A
AA
Rahmeh
Benjamin
B
Morin
Andreas D
AD
Schenk
Bo
B
Liang
Bianca S
BS
Heinrich
Vesna
V
Brusic
Thomas
T
Walz
Sean P J
SP
Whelan
D015153:Blotting, Western; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D013058:Mass Spectrometry; D008854:Microscopy, Electron; D008954:Models, Biological; D019590:Nucleocapsid Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D011487:Protein Conformation; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism*; D018116:Vesiculovirus / Q000201:enzymology*; D014764:Viral Proteins / Q000378:metabolism; D015678:Viral Structural Proteins / Q000378:metabolism*; D014779:Virus Replication / Q000502:physiology*
D019590:Nucleocapsid Proteins; D010750:Phosphoproteins; D014764:Viral Proteins; D015678:Viral Structural Proteins; C040530:L protein, vesicular stomatitis virus; D012324:RNA-Dependent RNA Polymerase