基因转录调控与早期三维生命体模式的构建

从分子生物学的角度而言,胚胎发育就是基因的时空调控过程,从而构建动物的三维模式.顺式调控是发育基因的基本原理;转录调控因子的激活与抑制决定了细胞分化与结构形成.     

Growth factor superfamilies and mammalian embryogenesis

With the availability of amino acid and nucleotide sequence information has come the realization that growth factors can be clustered in to superfamilies. Several of these superfamilies contain molecules that were not initially identified because of growth-promoting activities; rather they were discovered through their ability to regulate other processes. Certain members of these superfamilies are present during early mammalian embryogenesis. However, until recently, it has been difficult to manipulate the developing mammalian embryo to observe directly the effects of inappropriate, excessive, or reduced expression of these molecules. Despite this limitation, at least some of these molecules have been implicated in the control of differentiation and morphogenesis, two actions unpredicted from the cell biology of most of the growth factors. Moreover, these actions are reflected in nonmammalian species where homologues of the mammalian growth factors control crucial steps in the choice of developmental fate. This review describes five growth factor superfamilies and the role these molecules may have in controlling proliferation, differentiation, and morphogenesis during mammalian development.