[Targeted modification of CCR5 gene in rabbits by TALEN]

The lack of suitable animal model for HIV-1 infection has become a bottleneck for the development of AIDS vaccines and drugs. Wild-type rabbits can be infected by HIV-1 persistently and HIV-1 can be efficiently replicated resulting in syncytia in rabbit cell line co-expressing human CD4 and CCR5.Therefore, a rabbit highly expressing human CD4 and CCR5 may be an ideal animal model for AIDS disease study. In the present report, by using the efficient gene targeting technology, transcription activator-like effector nuclease (TALEN), we explored the feasibility of generating a HIV-1 model by knocking in human CD4 and CCR5 into rabbit genome. First we constructed two TALEN vectors targeting rabbit CCR5 gene and a vector with homologous arms. TALEN mRNAs and donor DNA were then co-injected into fertilized oocytes. After 3?5 days, 24 embryos were collected and used to conduct mutation analysis with PCR and sequencing. All the 24 embryos were detected with CCR5 knockouts and 5 were human CD4 and CCR5 knockins. Our results laid a foundation for establishing a new animal model for the study of AIDS.