In utero complementation of a neural crest-derived melanocyte defect using cell directed gene transfer

This study describes an in utero approach for overexpressing genes in a cell‐type directed manner. It uses an avian leukosis retroviral expression system coupled with a transgenic mouse line expressing the viral receptor tv‐a from a tissue‐specific promoter (RCAS‐TVA system) (Federspiel et al., 1994, and reviewed in Fisher et al., 1999). A transgenic mouse line was generated expressing tv‐a from the Dopachrome tautomerase promoter (DCT‐tv‐a) in embryonic melanocyte precursors (melanoblasts). RCAS virus encoding β‐galactosidase (RCAS‐LacZ) or tyrosinase (RCAS‐Tyr) was injected in utero into embryonic day 12.5 albino (tyrosinase inactive) mouse embryos. Animals were analyzed for β‐galactosidase activity or tyrosinase activity (hair pigmentation). RCAS gene expression was detected in 44% and 25% of the transgenic mice, respectively. We demonstrate the RCAS‐TVA system coupled with the DCT‐tv‐a line of mice can be used for in utero infection. genesis 30:70–76, 2001. © 2001 Wiley‐Liss, Inc.