title: Soluble CPG15 expressed during early development rescues cortical progenitors from apoptosis.
abstract: The balance between proliferation and apoptosis is critical for proper development of the nervous system. Yet, little is known about molecules that regulate apoptosis of proliferative neurons. Here we identify a soluble, secreted form of CPG15 expressed in embryonic rat brain regions undergoing rapid proliferation and apoptosis, and show that it protects cultured cortical neurons from apoptosis by preventing activation of caspase 3. Using a lentivirus-delivered small hairpin RNA, we demonstrate that endogenous CPG15 is essential for the survival of undifferentiated cortical progenitors in vitro and in vivo. We further show that CPG15 overexpression in vivo expands the progenitor pool by preventing apoptosis, resulting in an enlarged, indented cortical plate and cellular heterotopias within the ventricular zone, similar to the phenotypes of mutant mice with supernumerary forebrain progenitors. CPG15 expressed during mammalian forebrain morphogenesis may help balance neuronal number by countering apoptosis in specific neuroblasts subpopulations, thus influencing final brain size and shape.
authors.affiliation: The Picower Center for Learning and Memory, Departments of Brain and Cognitive Sciences and Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Putz
authors.forename: Corey
authors.initials: C
authors.lastname: Harwell
authors.forename: Elly
authors.initials: E
authors.lastname: Nedivi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology* / Q000196:embryology; D004622:Embryo, Mammalian; D018507:Gene Expression Regulation, Developmental; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells / Q000502:physiology*; D013997:Time Factors
chemical_list: C114622:Cpg15 protein, rat; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins