Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge, United Kindgom.
PLoS One. 2007 Feb 14;2(2):e213. doi: 10.1371/journal.pone.0000213.
The mesoderm of the amphibian embryo is formed through an inductive interaction in which vegetal cells of the blastula-staged embryo act on overlying equatorial cells. Candidate mesoderm-inducing factors include members of the transforming growth factor type beta family such as Vg1, activin B, the nodal-related proteins and derrière.
Microarray analysis reveals different functions for activin B and the nodal-related proteins during early Xenopus development. Inhibition of nodal-related protein function causes the down-regulation of regionally expressed genes such as chordin, dickkopf and XSox17alpha/beta, while genes that are mis-regulated in the absence of activin B tend to be more widely expressed and, interestingly, include several that are involved in cell cycle regulation. Consistent with the latter observation, cells of the involuting dorsal axial mesoderm, which normally undergo cell cycle arrest, continue to proliferate when the function of activin B is inhibited.
CONCLUSIONS/SIGNIFICANCE: These observations reveal distinct functions for these two classes of the TGF-beta family during early Xenopus development, and in doing so identify a new role for activin B during gastrulation.
两栖动物胚胎的中胚层是通过诱导相互作用形成的，在这种相互作用中，囊胚期胚胎的植物细胞作用于上方的赤道细胞。候选的中胚层诱导因子包括转化生长因子-β家族的成员，如 Vg1、激活素 B、与 nodal 相关的蛋白和 derrière。
微阵列分析揭示了激活素 B 和与 nodal 相关的蛋白在早期非洲爪蟾发育过程中的不同功能。抑制与 nodal 相关的蛋白功能会导致区域表达基因（如 chordin、 dickkopf 和 XSox17alpha/beta）的下调，而在没有激活素 B 的情况下失调的基因往往表达更广泛，有趣的是，其中包括几个参与细胞周期调控的基因。与后一种观察结果一致，当抑制激活素 B 的功能时，通常会经历细胞周期停滞的内卷背轴中胚层细胞继续增殖。
结论/意义：这些观察结果揭示了这两类 TGF-β 家族在早期非洲爪蟾发育过程中的不同功能，并因此确定了激活素 B 在原肠胚形成过程中的新作用。
