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
T. Wolff et al., 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, Journal of virology, 72(9), 1998, pp. 7170-7180
We used the yeast interaction trap system to identify a novel human 70
-kDa protein, termed NS1-binding protein (NS1-BP), which interacts wit
h the nonstructural NS1 protein of the influenza A virus. The genetic
interaction was confirmed by the specific coprecipitation of the NS1 p
rotein from solution by a glutathione S-transferase-NS1-BP fusion prot
ein and glutathione-Sepharose. NS1-BP contains an N-terminal BTB/POZ d
omain and five kelch-like tandem repeat elements of similar to 50 amin
o acids. In noninfected cells, affinity-purified antibodies localized
NS1-BP in nuclear regions enriched with the spliceosome assembly facto
r SC35, suggesting an association of NS1-BP with the cellular splicing
apparatus. In influenza A virus-infected cells, NS1-BP relocalized th
roughout the nucleoplasm and appeared distinct from the SC35 domains,
which suggests that NS1-BP function may be disturbed or altered. The a
ddition of a truncated NS1-BP mutant protein to a HeLa cell nuclear ex
tract efficiently inhibited pre-mRNA splicing but not spliceosome asse
mbly, This result could be explained by a possible dominant-negative e
ffect of the NS1-BP mutant protein and suggests a role of the wild-typ
e NS1-BP in promoting pre-mRNA splicing. These data suggest that the i
nhibition of splicing by the NS1 protein may be mediated by binding to
NS1-BP.