β-Catenin signals regulate cell growth and the balance between progenitor cell expansion and differentiation in the nervous system

• Published in: Developmental biology 2003-06, Vol.258 (2), p.406-418
• Main Authors: Zechner, Dietmar, Fujita, Yasuyuki, Hülsken, Jörg, Müller, Thomas, Walther, Ingrid, Taketo, Makoto M, Bryan Crenshaw, E, Birchmeier, Walter, Birchmeier, Carmen
• Format: Article
• Language: English
• Subjects: Alleles; Animals; Axin Protein; beta Catenin; Brain - cytology; Brain - embryology; Brain - metabolism; Bromodeoxyuridine - metabolism; Cell Differentiation; Cell Division; Central Nervous System - cytology; Central Nervous System - embryology; Central Nervous System - metabolism; Cytoskeletal Proteins - deficiency; Cytoskeletal Proteins - genetics; Cytoskeletal Proteins - physiology; Gene Expression Regulation, Developmental; Mice; Mice, Mutant Strains; Mice, Transgenic; Mutation; Neural stem cells; Neuronal progenitors; Neurons - cytology; Neurons - metabolism; Progenitor pool; Proliferation versus differentiation; Proto-Oncogene Proteins - metabolism; Signal Transduction; Spinal Cord - cytology; Spinal Cord - embryology; Spinal Cord - metabolism; Stem Cells - cytology; Stem Cells - metabolism; Trans-Activators - deficiency; Trans-Activators - genetics; Trans-Activators - physiology; Wnt Proteins; Wnt signaling; Zebrafish Proteins; β-Catenin
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1016/S0012-1606(03)00123-4

β-Catenin is an essential component of the canonical Wnt signaling system that controls decisive steps in development. We employed here two conditional β-catenin mutant alleles to alter β-catenin signaling in the central nervous system of mice: one allele to ablate β-catenin and the second allele to express a constitutively active β-catenin. The tissue mass of the spinal cord and brain is reduced after ablation of β-catenin, and the neuronal precursor population is not maintained. In contrast, the spinal cord and brain of mice that express activated β-catenin is much enlarged in mass, and the neuronal precursor population is increased in size. β-Catenin signals are thus essential for the maintenance of proliferation of neuronal progenitors, controlling the size of the progenitor pool, and impinging on the decision of neuronal progenitors to proliferate or to differentiate.