Stable expression of immunoglobulin gene V(D)J recombinase activity by gene transfer into 3T3 fibroblasts.

Using retroviral recombination substrates, we investigated the developmental stage of expression of V(D)J recombinase activity and the activation of recombinase activity in nonlymphoid cells. V(D)J recombinase activity was detected only in pre-B cells, but a DNA transfer protocol successfully activated V(D)J recombination in an NIH 3T3 cell line. The V(D)J recombinase activity was transferred in a second round of transfection and was then stably expressed in fibroblasts at a level comparable to that of a recombinationally active pre-B cell. It is likely that expression of a single, lymphoid-specific gene in a fibroblast is sufficient to confer V(D)J recombinase activity on that cell.