Signaling through FGF receptor-2 is required for lens cell survival and for withdrawal from the cell cycle during lens fiber cell differentiation.

Fibroblast growth factors (FGFs) play important roles in many aspects of development, including lens development. The lens is derived from the surface ectoderm and consists of an anterior layer of epithelial cells and elongated, terminally differentiated fiber cells that form the bulk of the tissue. FGF signaling has been implicated in lens induction, proliferation, and differentiation. To address the role of FGFs in lens development, we inactivated FGF receptor-2 (Fgfr2) using a Cre transgene that is expressed in all prospective lens cells from embryonic day 9.0. Inactivation of Fgfr2 shows that signaling through this receptor is not required for lens induction or for the proliferation of lens epithelial cells. However, Fgfr2 signaling is needed to drive lens fiber cells out of the cell cycle during their terminal differentiation. It also contributes to the normal elongation of primary lens fiber cells and to the survival of lens epithelial cells. Copyright 2005 Wiley-Liss, Inc