title: Analysis of the contribution of cellular and viral RNA to the packaging of APOBEC3G into HIV-1 virions.
abstract: BACKGROUND
  Efficient incorporation of the cellular cytidine deaminase APOBEC3G (APO3G) into HIV-1 virions is necessary for its antiviral activity. Even though cellular RNAs are known to be non-specifically incorporated into virus particles, we have previously found that encapsidation of APO3G into HIV-1 virions is specifically enhanced by viral genomic RNA. Intracellularly, APO3G was found to form large RNA-protein complexes involving a variety of cellular RNAs. The goal of this study was to investigate the possible contribution of host RNAs recently identified in intracellular APO3G ribonucleoprotein complexes to APO3G's encapsidation into HIV-1 virions.
  
  
  RESULTS
  Our results show that 7SL RNA, a component of signal recognition particles, and hY1, hY3, hY4, hY5 RNAs were present in intracellular APO3G complexes and were packaged into HIV-1 particles lacking viral genomic RNA unlike APO3G, which was not packaged in significant amounts into genomic RNA-deficient particles. These results indicate that packaging of 7SL or hY RNAs is not sufficient for the packaging of APO3G into HIV-1 virions. We also tested the encapsidation of several other cellular RNAs including beta-actin, GAPDH, alpha-tubulin, and small nuclear RNAs and determined their effect on the packaging of APO3G into nascent virions. Again, we were unable to observe any correlation between APO3G encapsidation and the packaging of any of these cellular RNAs.
  
  
  CONCLUSIONS
  The results from this study support our previous conclusion that viral genomic RNA is a critical determinant for APO3G incorporation into HIV-1 virions. While most cellular RNAs tested in this study were packaged into viruses or virus-like particles we failed to identify a correlation between APO3G encapsidation and the packaging of these cellular RNAs.
authors.affiliation: Laboratory of Molecular Microbiology, Viral Biochemistry Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0460, USA. mkhan@niaid.nih.gov
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Khan
authors.forename: Ritu
authors.initials: R
authors.lastname: Goila-Gaur
authors.forename: Sandrine
authors.initials: S
authors.lastname: Opi
authors.forename: Eri
authors.initials: E
authors.lastname: Miyagi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Sandra
authors.initials: S
authors.lastname: Kao
authors.forename: Klaus
authors.initials: K
authors.lastname: Strebel
mesh_terms: D000071480:APOBEC-3G Deaminase; D003564:Cytidine Deaminase; D017931:DNA Primers; D016259:Genes, myc; D015497:HIV-1 / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D009700:Nucleoside Deaminases / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014771:Virion / Q000502:physiology*
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D012367:RNA, Viral; D012097:Repressor Proteins; D009700:Nucleoside Deaminases; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase