Thorpe C J, Schlesinger A, Bowerman B
Howard Hughes Medical Institute and the Dept of Pharmacology, University of Washington, Pharmacology Box 357370, Seattle, WA 98195-7370, USA.
Trends Cell Biol. 2000 Jan;10(1):10-7. doi: 10.1016/s0962-8924(99)01672-4.
Wnt proteins are secreted, cysteine-rich glycoprotein ligands with numerous roles during animal development. Recent studies of endoderm induction during embryogenesis in the nematode Caenorhabditis elegans challenge the prevailing view that Wnt signalling specifies cell fate by converting transcriptional repressors into activators. Instead, a mitogen-activated protein kinase (MAPK)-related pathway converges with Wnt signalling in C. elegans to relieve transcriptional repression. Furthermore, Wnt signalling induces endoderm in part by aligning the mitotic spindle in a responding cell along the anterior-posterior body axis. To orient mitotic spindles, Wnt signalling might directly target the cytoskeleton, prior to any regulation of gene transcription in responding cells.
Wnt蛋白是分泌型、富含半胱氨酸的糖蛋白配体，在动物发育过程中发挥着多种作用。近期对线虫秀丽隐杆线虫胚胎发生过程中内胚层诱导的研究，对普遍认为的Wnt信号通过将转录抑制因子转化为激活因子来决定细胞命运的观点提出了挑战。相反，在秀丽隐杆线虫中，一条与丝裂原活化蛋白激酶（MAPK）相关的信号通路与Wnt信号通路汇聚，以解除转录抑制。此外，Wnt信号通路部分通过使应答细胞中的有丝分裂纺锤体沿前后体轴排列来诱导内胚层。为了使有丝分裂纺锤体定向，Wnt信号通路可能在应答细胞中对基因转录进行任何调控之前，直接作用于细胞骨架。
