Tethering human immunodeficiency virus type 1 preintegration complexes to target DNA promotes integration at nearby sites.
Integration of retroviral cDNA in vivo is normally not sequence specific with respect to the integration target DNA. We have been investigating methods for directing the integration of retroviral DNA to predetermined sites, with the dual goal of understanding potential mechanisms governing normal site selection and developing possible methods for gene therapy. To this end, we have fused retroviral integrase enzymes to sequence-specific DNA-binding domains and investigated target site selection by the resulting proteins. In a previous study, we purified and analyzed a fusion protein composed of human immunodeficiency virus integrase linked to the DNA-binding domain of lambda repressor. This fusion could direct selective integration in vitro into target DNA containing lambda repressor binding sites. Here we investigate the properties of a fusion integrase in the context of a human immunodeficiency virus provirus. We used a fusion of integrase to the DNA binding domain of the zinc finger protein zif268 (IN-zif). Initially we found that the fusion was highly detrimental to replication as measured by the multinuclear activation of a galactosidase indicator (MAGI) assay for infected centers. However, we found that viruses containing mixtures of wild-type integrase and IN-zif were infectious. We prepared preintegration complexes from cells infected with these viruses and found that such complexes directed increased integration near zif268 recognition sites.
Bushman
F D
FD
Infectious Disease Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Miller
M D
MD
D002461:Cell Line, Transformed; D004247:DNA; D004268:DNA-Binding Proteins / Q000235:genetics*; D051766:Early Growth Response Protein 1; D019427:HIV Integrase / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics* / Q000472:pathogenicity; D006801:Humans; D017874:Immediate-Early Proteins; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D016662:Virus Integration
D004268:DNA-Binding Proteins; C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; D017874:Immediate-Early Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D004247:DNA; D019427:HIV Integrase