title: Characterization of the HIV-1 RNA associated proteome identifies Matrin 3 as a nuclear cofactor of Rev function.
abstract: BACKGROUND
  Central to the fully competent replication cycle of the human immunodeficiency virus type 1 (HIV-1) is the nuclear export of unspliced and partially spliced RNAs mediated by the Rev posttranscriptional activator and the Rev response element (RRE).
  
  
  RESULTS
  Here, we introduce a novel method to explore the proteome associated with the nuclear HIV-1 RNAs. At the core of the method is the generation of cell lines harboring an integrated provirus carrying RNA binding sites for the MS2 bacteriophage protein. Flag-tagged MS2 is then used for affinity purification of the viral RNA. By this approach we found that the viral RNA is associated with the host nuclear matrix component MATR3 (Matrin 3) and that its modulation affected Rev activity. Knockdown of MATR3 suppressed Rev/RRE function in the export of unspliced HIV-1 RNAs. However, MATR3 was able to associate with Rev only through the presence of RRE-containing viral RNA.
  
  
  CONCLUSIONS
  In this work, we exploited a novel proteomic method to identify MATR3 as a cellular cofactor of Rev activity. MATR3 binds viral RNA and is required for the Rev/RRE mediated nuclear export of unspliced HIV-1 RNAs.
authors.affiliation: Laboratory of Molecular Virology, International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano, 99, 34012 Trieste, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Kula
authors.forename: Jessica
authors.initials: J
authors.lastname: Guerra
authors.forename: Anna
authors.initials: A
authors.lastname: Knezevich
authors.forename: Danijela
authors.initials: D
authors.lastname: Kleva
authors.forename: Michael P
authors.initials: MP
authors.lastname: Myers
authors.forename: Alessandro
authors.initials: A
authors.lastname: Marcello
mesh_terms: D021581:Active Transport, Cell Nucleus; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D015658:HIV Infections / Q000235:genetics / Q000378:metabolism* / Q000821:virology; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D034521:Nuclear Matrix-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D020543:Proteome / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D054321:rev Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism*
chemical_list: C518587:MATR3 protein, human; D034521:Nuclear Matrix-Associated Proteins; D020543:Proteome; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D054321:rev Gene Products, Human Immunodeficiency Virus