title: Association of functional influenza viral proteins and RNAs with nuclear chromatin and sub-chromatin structure.
abstract: Transcription and replication of the influenza virus genome occur in the nucleus. However, the intra-nuclear localization of viral RNP complexes and the function of nuclear domains involved in viral transcription and replication, if any, are not well known. In the present study, we determined the intra-nuclear localization of viral proteins and viral RNAs and the in vitro RNA synthesis activity of viral RNP complexes associated with distinct nuclear fractions prepared from infected nuclei. A majority of viral RNA polymerases and M1 were recovered in DNase-sensitive fractions, whereas some portion of RNA polymerases and approximately 25% of NP were tightly associated with so-called nuclear matrix fractions. The amount of vRNA associated with the nuclear matrix was significantly more than that of cRNA. The in vitro viral RNA synthesis activity was detected in DNase-insensitive fractions, including the nuclear matrix. In contrast, newly synthesized viral RNAs were recovered in the DNase-sensitive fraction. These observations suggest that vRNP complexes are, at least partially, associated with densely packed chromatin, where viral transcription and replication occur, and the newly synthesized vRNP complexes to be transported into the cytoplasm are released into the nucleoplasm.
authors.affiliation: Department of Infection Biology, Graduate School of Comprehensive Human Sciences and Institute of Basic Medical Sciences, University of Tsukuba, 1-1-1 Tennohdai, Tsukuba 305-8575, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Takizawa
authors.forename: Ken
authors.initials: K
authors.lastname: Watanabe
authors.forename: Kaoru
authors.initials: K
authors.lastname: Nouno
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Kyosuke
authors.initials: K
authors.lastname: Nagata
mesh_terms: D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000378:metabolism; D004285:Dogs; D009980:Influenza A virus / Q000378:metabolism*; D011485:Protein Binding; D012367:RNA, Viral / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D002843:Chromatin; D012367:RNA, Viral; D014764:Viral Proteins; D003851:Deoxyribonucleases