The integration profile of EIAV-based vectors

Abstract

Lentiviral vectors based on equine infectious anemia virus (EIAV) stably integrate into dividing and nondividing cells such as neurons, conferring long-term expression of their transgene. The integration profile of an EIAV vector was analyzed in dividing HEK293T cells, alongside an HIV-1 vector as a control, and compared to a random dataset generated in silico. A multivariate regression model was generated and the influence of the following parameters on integration site selection determined: (a) within/not within a gene, (b) GC content within 20 kb, (c) within 10 kb of a CpG island, (d) gene density within a 2-Mb window, and (e) chromosome number. The majority of the EIAV integration sites (68%; n = 458) and HIV-1 integration sites (72%; n = 162) were within a gene, and both vectors favored AT-rich regions. Sites within genes were examined using a second model to determine the influence of the gene-specific parameters, gene region, and transcriptional activity. Both EIAV and HIV-1 vectors preferentially integrated within active genes. Unlike the gammaretrovirus MLV, EIAV and HIV-1 vectors do not integrate preferentially into the promoter region or the 5' end of the transcription unit.

Role of the PWWP Domain of Lens Epithelium-derived Growth Factor (LEDGF)/p75 Cofactor in Lentiviral Integration Targeting

“…Estimation of integrated HIV copies by quantitative PCR (Fig. 5B) (16,63). EIAV integration sites were analyzed as described previously (17), yielding a total of 4923 integration sites.…”

Correction of the disease phenotype in the mouse model of Stargardt disease by lentiviral gene therapy

“…It has been shown that EIAV vectors preferentially integrate within active genes favoring AT-rich regions with a similar profile to that of HIV-1 vectors. 54 Furthermore, it has recently been demonstrated that the genotoxicity associated with lentiviral vectors is very low. 55 In conclusion, treatment of mouse models with lentiviral vectors carrying a reporter gene and/or the therapeutic gene, ABCA4, results in high-level and sustained expression of a transgene/protein in the injected area.…”

Ocular gene delivery using lentiviral vectors

“…75 HIV-1 or EIAV vectors in vitro, for example, consistently favour integration into active coding regions in dividing human cell lines, unlike retroviral MoLV vectors, which favour integration near transcriptional start sites. [76][77][78] HIV-1 integration in (post-mitotic) murine or rat RPE in vivo does not appear to show site preference for these regions, and instead shows near-random and uniform frequency of integration into genes and gene spare long interspersed nuclear elements, 79 suggesting that the risk of integrating HIV-1-related IM in post-mitotic tissues is probably low, and lower than in mitotically active cells. The in vivo intraocular vector integration profiles of lentiviruses other than HIV-1 have not been reported, but are also likely to be influenced by the degree of target cell mitosis.…”