LEDGF/p75 functions downstream from preintegration complex formation to effect gene-specific HIV-1 integration.
LEDGF/p75 directly interacts with lentiviral integrase proteins and can modulate their enzymatic activities and chromosomal association. A novel genetic knockout model was established that allowed us for the first time to analyze HIV-1 integration in the absence of LEDGF/p75 protein. Supporting a crucial role for the cofactor in viral replication, HIV-1 vector integration and reporter gene expression were significantly reduced in LEDGF-null cells. Yet, integrase processed the viral cDNA termini normally and maintained its local target DNA sequence preference during integration. Preintegration complexes extracted from knockout cells moreover supported normal levels of DNA strand transfer activity in vitro. In contrast, HIV-1 lost its strong bias toward integrating into transcription units, displaying instead increased affinity for promoter regions and CpG islands. Our results reveal LEDGF/p75 as a critical targeting factor, commandeering lentiviruses from promoter- and/or CpG island-proximal pathways that are favored by other members of Retroviridae. Akin to yeast retrotransposons, disrupting the lentiviral targeting mechanism significantly perturbs overall integration.
Shun
Ming-Chieh
MC
Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Division of AIDS, Harvard Medical School, Boston, Massachusetts 02115, USA.
Raghavendra
Nidhanapati K
NK
Vandegraaff
Nick
N
Daigle
Janet E
JE
Hughes
Siobhan
S
Kellam
Paul
P
Cherepanov
Peter
P
Engelman
Alan
A
D048868:Adaptor Proteins, Signal Transducing / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D016384:Consensus Sequence; D018899:CpG Islands; D004247:DNA / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015497:HIV-1 / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D019426:Integrases / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D009052:Leukemia Virus, Murine / Q000472:pathogenicity; D051379:Mice; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D016662:Virus Integration / Q000235:genetics / Q000502:physiology*
D048868:Adaptor Proteins, Signal Transducing; D036341:Intercellular Signaling Peptides and Proteins; C504650:Psip1 protein, mouse; D014157:Transcription Factors; C119380:lens epithelium-derived growth factor; D004247:DNA; D019426:Integrases