title: Neurogenic role of Gcm transcription factors is conserved in chicken spinal cord.
abstract: Although glial cells missing (gcm) genes are known as glial determinants in the fly embryo, the role of vertebrate orthologs in the central nervous system is still under debate. Here we show for the first time that the chicken ortholog of fly gcm (herein referred to as c-Gcm1), is expressed in early neuronal lineages of the developing spinal cord and is required for neural progenitors to differentiate as neurons. Moreover, c-Gcm1 overexpression is sufficient to trigger cell cycle exit and neuronal differentiation in neural progenitors. Thus, c-Gcm1 expression constitutes a crucial step in the developmental cascade that prompts progenitors to generate neurons: c-Gcm1 acts downstream of proneural (neurogenin) and progenitor (Sox1-3) factors and upstream of NeuroM neuronal differentiation factor. Strikingly, this neurogenic role is not specific to the vertebrate gene, as fly gcm and gcm2 are also sufficient to induce the expression of neuronal markers. Interestingly, the neurogenic role is restricted to post-embryonic stages and we identify two novel brain neuronal lineages expressing and requiring gcm genes. Finally, we show that fly gcm and the chick and mouse orthologs induce expression of neural markers in HeLa cells. These data, which demonstrate a conserved neurogenic role for Gcm transcription factors, call for a re-evaluation of the mode of action of these genes during evolution.
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cedex, CU de Strasbourg, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Soustelle
authors.forename: Françoise
authors.initials: F
authors.lastname: Trousse
authors.forename: Cécile
authors.initials: C
authors.lastname: Jacques
authors.forename: Julian
authors.initials: J
authors.lastname: Ceron
authors.forename: Philippe
authors.initials: P
authors.lastname: Cochard
authors.forename: Cathy
authors.initials: C
authors.lastname: Soula
authors.forename: Angela
authors.initials: A
authors.lastname: Giangrande
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002454:Cell Differentiation; D002642:Chick Embryo; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004330:Drosophila / Q000196:embryology / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013116:Spinal Cord / Q000196:embryology* / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D014162:Transfection
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C102805:GCM protein, Drosophila; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors