NS1-Binding protein (NS1-BP): a novel human protein that interacts with the influenza A virus nonstructural NS1 protein is relocalized in the nuclei of infected cells.
We used the yeast interaction trap system to identify a novel human 70-kDa protein, termed NS1-binding protein (NS1-BP), which interacts with the nonstructural NS1 protein of the influenza A virus. The genetic interaction was confirmed by the specific coprecipitation of the NS1 protein from solution by a glutathione S-transferase-NS1-BP fusion protein and glutathione-Sepharose. NS1-BP contains an N-terminal BTB/POZ domain and five kelch-like tandem repeat elements of approximately 50 amino acids. In noninfected cells, affinity-purified antibodies localized NS1-BP in nuclear regions enriched with the spliceosome assembly factor SC35, suggesting an association of NS1-BP with the cellular splicing apparatus. In influenza A virus-infected cells, NS1-BP relocalized throughout the nucleoplasm and appeared distinct from the SC35 domains, which suggests that NS1-BP function may be disturbed or altered. The addition of a truncated NS1-BP mutant protein to a HeLa cell nuclear extract efficiently inhibited pre-mRNA splicing but not spliceosome assembly. This result could be explained by a possible dominant-negative effect of the NS1-BP mutant protein and suggests a role of the wild-type NS1-BP in promoting pre-mRNA splicing. These data suggest that the inhibition of splicing by the NS1 protein may be mediated by binding to NS1-BP.
Institut für Virologie, Philipps-Universität Marburg, 35037 Marburg, Germany. wolfft@mailer.uni-marburg.de
T
T
Wolff
R E
RE
O'Neill
P
P
Palese
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002461:Cell Line, Transformed; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005260:Female; D006367:HeLa Cells; D006801:Humans; D009980:Influenza A virus / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012322:RNA Precursors; D012326:RNA Splicing; D016601:RNA-Binding Proteins; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D014407:Tumor Cells, Cultured; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*
D002352:Carrier Proteins; D018076:DNA, Complementary; C085820:INS1 protein, influenza virus; C114207:IVNS1ABP protein, human; D009687:Nuclear Proteins; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D017361:Viral Nonstructural Proteins