Ded1p, a conserved DExD/H-box translation factor, can promote yeast L-A virus negative-strand RNA synthesis in vitro.
Viruses are intracellular parasites that must use the host machinery to multiply. Identification of the host factors that perform essential functions in viral replication is thus of crucial importance to the understanding of virus-host interactions. Here we describe Ded1p, a highly conserved DExD/H-box translation factor, as a possible host factor recruited by the yeast L-A double-stranded RNA (dsRNA) virus. We found that Ded1p interacts specifically and strongly with Gag, the L-A virus coat protein. Further analysis revealed that Ded1p interacts with the L-A virus in an RNA-independent manner and, as a result, L-A particles can be affinity purified via this interaction. The affinity-purified L-A particles are functional, as they are capable of synthesizing RNA in vitro. Critically, using purified L-A particles, we demonstrated that Ded1p specifically promotes L-A dsRNA replication by accelerating the rate of negative-strand RNA synthesis in vitro. In light of these data, we suggest that Ded1p may be a part of the long sought after activity shown to promote yeast viral dsRNA replication. This and the fact that Ded1p is also required for translating brome mosaic virus RNA2 in yeast thus raise the intriguing possibility that Ded1p is one of the key host factors favored by several evolutionarily related RNA viruses, including the human hepatitis C virus.
Chong
Jean-Leon
JL
Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA.
Chuang
Ray-Yuan
RY
Tung
Luh
L
Chang
Tien-Hsien
TH
D018797:Cell Cycle Proteins / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D017124:Conserved Sequence; D053487:DEAD-box RNA Helicases; D005656:Fungal Proteins / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D015683:Gene Products, gag / Q000378:metabolism; D020365:RNA Helicases / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D012367:RNA, Viral / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000821:virology*; D029701:Saccharomyces cerevisiae Proteins; D019197:Totivirus / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D014158:Transcription, Genetic; D014771:Virion / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D014779:Virus Replication
D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D015683:Gene Products, gag; D012367:RNA, Viral; D029701:Saccharomyces cerevisiae Proteins; C492152:DED1 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases