3T3 cell integration and differentiative potential during limb development in the mouse.

Abstract

In this study we have investigated the ability of embryonic mouse limb cells to induce the differentiation of 3T3 cells both in vivo and in vitro. Using the exo utero surgical technique we introduced labeled 3T3 cells into the embryonic mouse limb and monitored their subsequent development. We found no indication that the normal pattern of tissue differentiation was perturbed; rather we observed that 3T3 cells were closely associated with a variety of limb mesodermal tissues which include muscle, tendon, and ligament. In very rare instances did we observe 3T3 cells associated with cartilage. To further investigate the differentiative potential of 3T3 cells we cocultured labeled 3T3 cells with limb cells under conditions that favored either cartilage or muscle differentiation. The results from these experiments suggest that 3T3 cells avoid regions of chondrogenesis and rarely participate in myotube formation. We conclude that 3T3 cells are not responding to differentiation signals present in the developing limb, but rather are responding to signals involved in growth and tissue morphogenesis.