RoXaN, a novel cellular protein containing TPR, LD, and zinc finger motifs, forms a ternary complex with eukaryotic initiation factor 4G and rotavirus NSP3.
Rotavirus mRNAs are capped but not polyadenylated, and viral proteins are translated by the cellular translation machinery. This is accomplished through the action of the viral nonstructural protein NSP3, which specifically binds the 3' consensus sequence of viral mRNAs and interacts with the eukaryotic translation initiation factor eIF4G I. To further our understanding of the role of NSP3 in rotavirus replication, we looked for other cellular proteins capable of interacting with this viral protein. Using the yeast two-hybrid assay, we identified a novel cellular protein-binding partner for rotavirus NSP3. This 110-kDa cellular protein, named RoXaN (rotavirus X protein associated with NSP3), contains a minimum of three regions predicted to be involved in protein-protein or nucleic acid-protein interactions. A tetratricopeptide repeat region, a protein-protein interaction domain most often found in multiprotein complexes, is present in the amino-terminal region. In the carboxy terminus, at least five zinc finger motifs are observed, further suggesting the capacity of RoXaN to bind other proteins or nucleic acids. Between these two regions exists a paxillin leucine-aspartate repeat (LD) motif which is involved in protein-protein interactions. RoXaN is capable of interacting with NSP3 in vivo and during rotavirus infection. Domains of interaction were mapped and correspond to the dimerization domain of NSP3 (amino acids 163 to 237) and the LD domain of RoXaN (amino acids 244 to 341). The interaction between NSP3 and RoXaN does not impair the interaction between NSP3 and eIF4G I, and a ternary complex made of NSP3, RoXaN, and eIF4G I can be detected in rotavirus-infected cells, implicating RoXaN in translation regulation.
Vitour
Damien
D
Virologie Moléculaire et Structurale, Unité Mixte de Recherche, CNRS-INRA, 91198 Gif-sur-Yvette, France.
Lindenbaum
Pierre
P
Vende
Patrice
P
Becker
Michelle M
MM
Poncet
Didier
D
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002460:Cell Line; D018076:DNA, Complementary / Q000235:genetics; D039603:Eukaryotic Initiation Factor-4G; D019143:Evolution, Molecular; D015870:Gene Expression; D006801:Humans; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010448:Peptide Initiation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012401:Rotavirus / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D012400:Rotavirus Infections / Q000235:genetics / Q000378:metabolism / Q000821:virology; D020798:Two-Hybrid System Techniques; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016335:Zinc Fingers
D018076:DNA, Complementary; C113920:EIF4G1 protein, human; D039603:Eukaryotic Initiation Factor-4G; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; C082740:NSP3 protein, Rotavirus; D010446:Peptide Fragments; D010448:Peptide Initiation Factors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D017361:Viral Nonstructural Proteins; D014764:Viral Proteins; C484647:ZC3H7B protein, human