Efficient gene transfer into mouse embryonic stem cells with adenovirus vectors

Efficient and transient gene transfer into embryonic stem (ES) cells is expected to be of use for basic studies in developmental biology and for applications in regenerative medicine. Here, we report the development of an adenovirus (Ad) vector that efficiently expresses foreign genes in mouse ES (mES) cells. We prepared four LacZ-expressing Ad vectors, each of which contained one of the following: Rous sarcoma virus (RSV), cytomegalovirus (CMV), beta-actin promoter/CMV enhancer (CA), or EF-1alpha promoter. While the RSV and CMV promoters were inactive in mES cells, the CA and EF-1alpha promoters strongly drove LacZ expression in more than 90% of the mES cells. The EF-1alpha promoter was found to be slightly more efficient than the CA promoter. mES cells were found to express the Ad primary receptor, coxsackievirus and adenovirus receptor, suggesting that while Ad vectors could introduce the exogenous gene into mES cells, the choice of a suitable promoter was critical for efficient gene expression. Fiber-mutant Ad vectors containing RGD or polylysine peptide on the fiber knob mediated efficient LacZ expression, not only in mES cells, but also in feeder cells. Exogenous expression of Oct-3/4 or the dominant-negative mutant of STAT3 (STAT3F) by conventional Ad vectors containing the EF-1alpha promoter promoted the differentiation of mES cells into the cells of three germ layers, and STAT3F-mediated differentiation was rescued by the coexpression of Nanog. These results suggest that Ad vectors can be used for basic research using ES cells and that they may be of great utility for therapeutic applications in gene-modified regenerative medicine based on ES cells.