A local Wnt-3a signal is required for development of the mammalian hippocampus.
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.
Lee
S M
SM
Department of Molecular Biology, The Biolabs, Harvard University, Cambridge, MA 02138, USA.
Tole
S
S
Grove
E
E
McMahon
A P
AP
D000818:Animals; D002540:Cerebral Cortex / Q000196:embryology; D005314:Embryonic and Fetal Development / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D006624:Hippocampus / Q000196:embryology*; D008322:Mammals; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000166:cytology / Q000502:physiology; D011506:Proteins / Q000235:genetics* / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D013234:Stem Cells / Q000166:cytology / Q000502:physiology; D013687:Telencephalon / Q000196:embryology; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein
D011506:Proteins; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein; C555511:Wnt3a protein, mouse; C490603:Wnt8b protein, mouse