Direct interaction of cellular hnRNP-F and NS1 of influenza A virus accelerates viral replication by modulation of viral transcriptional activity and host gene expression.
To investigate novel NS1-interacting proteins, we conducted a yeast two-hybrid analysis, followed by co-immunoprecipitation assays. We identified heterogeneous nuclear ribonucleoprotein F (hnRNP-F) as a cellular protein interacting with NS1 during influenza A virus infection. Co-precipitation assays suggest that interaction between hnRNP-F and NS1 is a common and direct event among human or avian influenza viruses. NS1 and hnRNP-F co-localize in the nucleus of host cells, and the RNA-binding domain of NS1 directly interacts with the GY-rich region of hnRNP-F determined by GST pull-down assays with truncated proteins. Importantly, hnRNP-F expression levels in host cells indicate regulatory role on virus replication. hnRNP-F depletion by small interfering RNA (siRNA) shows 10- to 100-fold increases in virus titers corresponding to enhanced viral RNA polymerase activity. Our results delineate novel mechanism of action by which NS1 accelerates influenza virus replication by modulating normal cellular mRNA processes through direct interaction with cellular hnRNP-F protein.
Lee
Jun Han
JH
College of Medicine and Medical Research Institute, Chungbuk National University, 12 Gaeshin-Dong Heungduk-Ku, Cheongju 361-763, Republic of Korea.
Kim
Sung-Hak
SH
Pascua
Philippe Noriel Q
PN
Song
Min-Suk
MS
Baek
Yun Hee
YH
Jin
Xun
X
Choi
Joong-Kook
JK
Kim
Chul-Joong
CJ
Kim
Hyunggee
H
Choi
Young Ki
YK
D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry; D015870:Gene Expression; D020868:Gene Silencing; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D053118:Influenza A Virus, H1N1 Subtype / Q000502:physiology*; D053124:Influenza A Virus, H5N1 Subtype / Q000502:physiology*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques; D017361:Viral Nonstructural Proteins / Q000378:metabolism*; D014779:Virus Replication
D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; C085820:INS1 protein, influenza virus; D017361:Viral Nonstructural Proteins