Figure 3.

Transient expression of CBX1-LEDGF_325-530 retargets LV integration into CBX1-rich heterochromatin regions. (a) Western blot analysis showing protein expression of CBX1-LEDGF_325-530(D366N) and endogenous LEDGF/p75 (mock) compared with WT HeLaP4 cells 48 hours after mRNA electroporation. Loading was controlled by α-tubulin. (b) Following mRNA electroporation, WT HeLaP4 cells were transduced with LV_eGFP-T2A-fLuc. Integrated vector copies were measured by quantitative PCR. (c) Correlations were made between integration sites and the density of a panel of 39 histone modifications. Associations of integration and histone methylation/acetylation were quantified using ROC areas, comparing the association of integration site data sets with the frequency in corresponding MRC sets. A ROC area scale is shown along the bottom of the panel. Tile color indicates whether a specific feature is favored (blue, enrichment relative to random) or disfavored (yellow, negative correlation compared with random) for integration (10 kb window) in the respective data sets relative to their MRCs. P values showing significance of departures from mock-treated WT cells (overlaid with dashes) are shown with asterisks (***P < 0.001, Wald statistics referred to χ² distribution compared with mock). CBX1, heterochromatin protein 1β LEDGF/p75, lens epithelium-derived growth factor; LV, lentiviral vector; MRC, matched random control; ROC, receiver operating characteristic; WT, wild-type.