The heat shock protein 70 cochaperone YDJ1 is required for efficient membrane-specific flock house virus RNA replication complex assembly and function in Saccharomyces cerevisiae.
The assembly of RNA replication complexes on intracellular membranes is an essential step in the life cycle of positive-sense RNA viruses. We have previously shown that Hsp90 chaperone complex activity is essential for efficient Flock House virus (FHV) RNA replication in Drosophila melanogaster S2 cells. To further explore the role of cellular chaperones in viral RNA replication, we used both pharmacologic and genetic approaches to examine the role of the Hsp90 and Hsp70 chaperone systems in FHV RNA replication complex assembly and function in Saccharomyces cerevisiae. In contrast to results with insect cells, yeast deficient in Hsp90 chaperone complex activity showed no significant decrease in FHV RNA replication. However, yeast with a deletion of the Hsp70 cochaperone YDJ1 showed a dramatic reduction in FHV RNA replication that was due in part to reduced viral RNA polymerase accumulation. Furthermore, the absence of YDJ1 did not reduce FHV RNA replication when the viral RNA polymerase and replication complexes were retargeted from the mitochondria to the endoplasmic reticulum. These results identify YDJ1 as an essential membrane-specific host factor for FHV RNA replication complex assembly and function in S. cerevisiae and are consistent with known differences in the role of distinct chaperone complexes in organelle-specific protein targeting between yeast and higher eukaryotes.
Department of Internal Medicine, Division of Infectious Diseases, 5220E MSRB III, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-0640, USA.
Spencer A
SA
Weeks
David J
DJ
Miller
D000818:Animals; D002462:Cell Membrane / Q000737:chemistry; D004331:Drosophila melanogaster / Q000821:virology*; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000502:physiology*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D007304:Insect Viruses / Q000235:genetics*; D018832:Molecular Chaperones / Q000235:genetics / Q000502:physiology*; D012328:RNA Viruses / Q000235:genetics*; D012367:RNA, Viral / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000821:virology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*; D014764:Viral Proteins / Q000032:analysis / Q000378:metabolism
D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D018832:Molecular Chaperones; D012367:RNA, Viral; D029701:Saccharomyces cerevisiae Proteins; D014764:Viral Proteins; C070319:YDJ1 protein, S cerevisiae