Influenza A virus matrix protein 1 interacts with hTFIIIC102-s, a short isoform of the polypeptide 3 subunit of human general transcription factor IIIC.

Influenza A virus matrix protein 1 (M1) is a multifunctional protein that plays important roles during replication, assembly and budding of the virus. To search for intracellular protein components that interact with M1 protein and explore the potential roles of these interactions in the pathogenesis of influenza virus infection, 11 independent proteins, including hTFIIIC102-s protein, encoding a short isoform of the TFIIIC102 subunit of the human TFIIIC transcription factor, were screened from a human cell cDNA library using a yeast two-hybrid technique. The interaction between M1 protein and hTFIIIC102-s was studied in more detail. Mapping assays showed that the N-terminal globular region (amino acids 1-164) of the M1 protein and the five tandem tetratricopeptide repeats (TPR1-5, amino acids 149-362) in hTFIIIC102-s were necessary for the interaction. The interaction was confirmed by both glutathione-S-transferase (GST) pull-down assays and coimmunoprecipitation assays. In addition, coexpression of hTFIIIC102-s with M1 in HeLa cells inhibited the translocation of M1 into the nucleus. Taken together, the present data indicate that hTFIIIC102-s can interact with the structural M1 protein of the influenza virus, which provides a novel clue toward further understanding of the roles of M1 protein in the interactions between influenza virus and host cells.