The influenza virus NS1 protein forms multimers in vitro and in vivo.
The NS1 protein of the influenza A virus inhibits both the nuclear export of mRNA and pre-mRNA splicing. Two functional domains, an RNA-binding domain and an effector domain, have been identified in this protein. Here we demonstrate that the NS1 protein exists as a dimer in vitro both in the absence of its RNA target and when it is bound to a specific RNA target, U6 snRNA. This indicates that it is most likely the dimer that binds to the RNA target. Mutational analysis indicated that the RNA-binding and dimerization domains are coincident. Multimerization also occurs in vivo, as assayed using the yeast two-hybrid system. In contrast to the situation in vitro, multimerization in vivo was mediated by not only the RNA-binding domain but also the effector domain. This suggests that multimerization in vivo involves a cellular protein cofactor that bridges more than one NS1 protein molecule together via their effector domains.
Nemeroff
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ME
Department of Molecular Biology and Biochemistry, Rutgers, State University of New Jersey, Piscataway 08855-1179, USA.
Qian
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Krug
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D000595:Amino Acid Sequence; D005982:Glutathione Transferase / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009975:Orthomyxoviridae / Q000737:chemistry*; D011487:Protein Conformation; D012342:RNA, Small Nuclear / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017384:Sequence Deletion; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
C085820:INS1 protein, influenza virus; D012342:RNA, Small Nuclear; D011993:Recombinant Fusion Proteins; D017361:Viral Nonstructural Proteins; D005982:Glutathione Transferase