Interaction of HIV-1 integrase with DNA repair protein hRad18.
We have previously shown that human immunodeficiency virus-1 (HIV-1) integrase is an unstable protein and a substrate for the N-end rule degradation pathway. This degradation pathway shares its ubiquitin-conjugating enzyme, Rad6, with the post-replication/translesion DNA repair pathway. Because DNA repair is thought to play an essential role in HIV-1 integration, we investigated whether other molecules of this DNA repair pathway could interact with integrase. We observed that co-expression of human Rad18 induced the accumulation of an otherwise unstable form of HIV-1 integrase. This accumulation occurred even though hRAD18 possesses a RING finger domain, a structure that is generally associated with E3 ubiquitin ligase function and protein degradation. Evidence for an interaction between integrase and hRad18 was obtained through reciprocal co-immunoprecipitation. Moreover we found that a 162-residue region of hRad18 (amino acids 65-226) was sufficient for both integrase stabilization and interaction. Finally, we observed that HIV-1 integrase co-localized with hRad18 in nuclear structures in a subpopulation of co-transfected cells. Taken together, these findings identify hRad18 as a novel interacting partner of HIV-1 integrase and suggest a role for post-replication/translesion DNA repair in the retroviral integration process.
Mulder
Lubbertus C F
LC
Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NY 10016, USA.
Chakrabarti
Lisa A
LA
Muesing
Mark A
MA
D015153:Blotting, Western; D002460:Cell Line; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism*; D017353:Gene Deletion; D019427:HIV Integrase / Q000378:metabolism*; D006801:Humans; D008856:Microscopy, Fluorescence; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012190:Retroviridae / Q000235:genetics; D014162:Transfection; D044767:Ubiquitin-Protein Ligases
D004268:DNA-Binding Proteins; C485954:RAD18 protein, human; D044767:Ubiquitin-Protein Ligases; D019427:HIV Integrase