title: DBR1 siRNA inhibition of HIV-1 replication.
abstract: BACKGROUND
  HIV-1 and all retroviruses are related to retroelements of simpler organisms such as the yeast Ty elements. Recent work has suggested that the yeast retroelement Ty1 replicates via an unexpected RNA lariat intermediate in cDNA synthesis. The putative genomic RNA lariat intermediate is formed by a 2'-5' phosphodiester bond, like that found in pre-mRNA intron lariats and it facilitates the minus-strand template switch during cDNA synthesis. We hypothesized that HIV-1 might also form a genomic RNA lariat and therefore that siRNA-mediated inhibition of expression of the human RNA lariat de-branching enzyme (DBR1) expression would specifically inhibit HIV-1 replication.
  
  
  RESULTS
  We designed three short interfering RNA (siRNA) molecules targeting DBR1, which were capable of reducing DBR1 mRNA expression by 80% and did not significantly affect cell viability. We assessed HIV-1 replication in the presence of DBR1 siRNA and found that DBR1 knockdown led to decreases in viral cDNA and protein production. These effects could be reversed by cotransfection of a DBR1 cDNA indicating that the inhibition of HIV-1 replication was a specific effect of DBR1 underexpression.
  
  
  CONCLUSIONS
  These data suggest that DBR1 function may be needed to debranch a putative HIV-1 genomic RNA lariat prior to completion of reverse transcription.
authors.affiliation: Department of Molecular Biology & Biochemistry, 2230 McGaugh Hall, University of California, Irvine, Irvine, CA 92697-3900, USA. yey@uci.edu
authors.forename: Ying
authors.initials: Y
authors.lastname: Ye
authors.forename: Jessica
authors.initials: J
authors.lastname: De Leon
authors.forename: Noriko
authors.initials: N
authors.lastname: Yokoyama
authors.forename: Yathi
authors.initials: Y
authors.lastname: Naidu
authors.forename: David
authors.initials: D
authors.lastname: Camerini
mesh_terms: D002460:Cell Line; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D012316:RNA Nucleotidyltransferases / Q000037:antagonists & inhibitors* / Q000235:genetics; D012326:RNA Splicing; D012333:RNA, Messenger / Q000032:analysis; D034741:RNA, Small Interfering / Q000494:pharmacology*; D014158:Transcription, Genetic; D014162:Transfection; D014779:Virus Replication
chemical_list: D012333:RNA, Messenger; D034741:RNA, Small Interfering; D012316:RNA Nucleotidyltransferases; C048135:lariat debranching enzyme