FOCAL ADHESION KINASE IS NOT ESSENTIAL FOR IN-VITRO AND IN-VIVO DIFFERENTIATION OF ES CELLS

Focal adhesion kinase, FAK, is a unique protein tyrosine kinase found in cellular focal adhesions. It is widely expressed and highly phospho rylated during embryogenesis. To examine the function of FAK in cell d ifferentiation, we made FAK-deficient embryonic stem (ES) cells by hom ologous recombination. However, FAK deficiency did not interfere with differentiation of the ES cells into cells of three germ layers when i mplanted subcutaneously into nude mice or when treated with retinoic a cid in vitro, nor was there any evidence of defects in hematopoiesis i n vitro. (C) 1995 Academic Press, Inc.