ИСТИНА

HIV-1 integration results in DNA gaps that should be repaired. Some factors of the non- homologous end-joining repair (NHEJ) supposedly participate in the post-integrational gap repair. However, the direct mechanisms of the NHEJ-mediated repair are not clear since lentiviral integration does not produce double-stranded DNA ends. We and others reported that Ku70 protein of the NHEJ directly binds HIV-1 integrase. Here, we identified the amino acids in HIV-1 integrase which are necessary for binding of Ku70. Here, we engineered HIV-1 based pseudovirus with mutant IN defective in Ku70 binding and generated heterozygous Ku70, Ku80 and DNA-PKcs knockout (KO) cells using CRISPR/Cas9. KO of either of these proteins or inhibition of DNA-PK activity substantially decreased the replication of HIV with native IN but not the mutant one. A qPCR-based assay for the gap repair efficiency measurement showed that HIV-1 with mutant IN was defective in DNA post-integrational repair, whereas the wild type virus displayed such a defect only when DNA-PK activity was reduced. This suggests that IN recruits DNA-PK to the site of HIV post-integrational repair due to Ku70 binding. Our data indicate the importance of interaction between HIV-1 IN and Ku70 in HIV-1 replication at the post- integrational repair step.