A tale of two signals: Wnt and Hedgehog in dentate neurogenesis.
It is now widely accepted that discrete regions of the adult brain contain stem cells that continue to generate new neurons. However, it remains unclear what molecular signals define the neurogenic niche and how such signals act on the heterogeneous cell populations within these regions. Here we discuss two recent studies that demonstrate the role of Wnt and Sonic Hedgehog signaling in neurogenic zones. Wnts act on neuronal precursors that mature and contribute to the dentate gyrus (DG), whereas Sonic Hedgehog affects the bona fide stem cells and transit amplifying cells (the partially committed progeny of stem cells). These studies further define how discrete populations of cells react to specific extracellular signals provided within the neurogenic niche to survive, proliferate, and form functional mature cell types.
Pozniak
Christine D
CD
Department of Neurology, Program in Neuroscience, University of California, San Francisco, CA 94143, USA.
Pleasure
Samuel J
SJ
D000818:Animals; D001253:Astrocytes / Q000166:cytology; D002454:Cell Differentiation / Q000502:physiology; D019070:Cell Lineage; D018891:Dentate Gyrus / Q000166:cytology*; D053823:Hedgehog Proteins; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics; D051379:Mice; D008959:Models, Neurological; D009024:Morphogenesis / Q000502:physiology; D009474:Neurons / Q000166:cytology*; D009836:Oligodendroglia / Q000166:cytology; D051381:Rats; D011960:Receptors, Estrogen / Q000187:drug effects / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology*; D013629:Tamoxifen / Q000494:pharmacology; D015534:Trans-Activators / Q000502:physiology*; D051153:Wnt Proteins / Q000502:physiology*; D000071676:Zinc Finger Protein GLI1
C498520:Gli1 protein, mouse; D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; C509239:SHH protein, human; C465570:Shh protein, mouse; D015534:Trans-Activators; D051153:Wnt Proteins; D000071676:Zinc Finger Protein GLI1; D013629:Tamoxifen