Transforming growth factor beta and mouse development

Transforming growth factor beta has many biological effects including the c ontrol of cellular growth, differentiation, migration and extracellular mat rix production; these are all processes essential for normal development. A lthough mice first generated more than eight years ago, bearing mutations i n TGF beta ligands demonstrated the importance of TGF beta -induced signal transduction pathways for development in mammals but complete functional an alysis is still lacking. Here, the current state-of-the-art in mouse develo pment is reviewed. As a basis for understanding function, the principle fea tures of mouse development over the 21 days of pregnancy are described and illustrated, from fertilization of the egg to mid-gestation when organogene sis is largely complete. This is completed with a description of when and w here TGF beta ligands, receptors and downstream signalling molecules are ex pressed as the mouse embryo develops. The functions of TGF beta in preimpla ntation development, in implantation of the embryos in the uterine wall and in postimplantation development are then described through a review of the literature on gene ablation of the ligands, receptors and downstream molec ules, or the ectopic expression of dominant negative forms of the receptors in vivo, which interfere with normal signal transduction. The evidence con firms multifunctional roles at all stages of development. Microsc. Res. Tec h. 52:374-386, 2001. (C) 2001 Wiley-Liss, Inc.