Lee S M, Tole S, Grove E, McMahon A P
Department of Molecular Biology, The Biolabs, Harvard University, Cambridge, MA 02138, USA.
Development. 2000 Feb;127(3):457-67. doi: 10.1242/dev.127.3.457.
The mechanisms that regulate patterning and growth of the developing cerebral cortex remain unclear. Suggesting a role for Wnt signaling in these processes, multiple Wnt genes are expressed in selective patterns in the embryonic cortex. We have examined the role of Wnt-3a signaling at the caudomedial margin of the developing cerebral cortex, the site of hippocampal development. We show that Wnt-3a acts locally to regulate the expansion of the caudomedial cortex, from which the hippocampus develops. In mice lacking Wnt-3a, caudomedial cortical progenitor cells appear to be specified normally, but then underproliferate. By mid-gestation, the hippocampus is missing or represented by tiny populations of residual hippocampal cells. Thus, Wnt-3a signaling is crucial for the normal growth of the hippocampus. We suggest that the coordination of growth with patterning may be a general role for Wnts during vertebrate development.
调节发育中大脑皮层的模式形成和生长的机制仍不清楚。多个Wnt基因在胚胎皮层中以选择性模式表达，这表明Wnt信号在这些过程中发挥作用。我们研究了Wnt-3a信号在发育中大脑皮层的尾内侧边缘（海马体发育的部位）所起的作用。我们发现，Wnt-3a在局部发挥作用，调节尾内侧皮层的扩张，而海马体正是从该区域发育而来。在缺乏Wnt-3a的小鼠中，尾内侧皮层祖细胞似乎正常特化，但随后增殖不足。到妊娠中期，海马体缺失或仅由少量残留的海马体细胞代表。因此，Wnt-3a信号对海马体的正常生长至关重要。我们认为，生长与模式形成的协调可能是Wnt在脊椎动物发育过程中的一个普遍作用。
