title: Comparative aspects of p73 and Reelin expression in Cajal-Retzius cells and the cortical hem in lizard, mouse and human.
abstract: Cajal-Retzius (CR) cells of the mammalian neocortex co-express the extracellular matrix protein Reelin and p73, a transcription factor involved in cell death and survival. Most neocortical CR cells derive from the cortical hem, with minor additional sources. We analyzed the distribution of Reelin and p73 immunoreactive (ir) neurons in the telencephalon of Lacerta galloti from early embryonic stages to hatching. Numerous Reelin-ir cells appeared in the pallial MZ from the preplate stage onward. Conversely, p73-ir cells were rare in the pallial preplate and not observed in the cortical plate. Subpallial p73-ir cells spread from the septum and the telencephalic-diencephalic boundary to the pial surface of the basal forebrain and amygdala, respectively, where they co-expressed Reelin and p73. A small group of Reelin/p73-ir CR cells appeared in a rudimentary cortical hem at the interface of the medial cortex and choroid plexus. Comparison with early embryonic stages of mice and humans showed similar foci of p73-ir cells in the septum and at the telencephalic-diencephalic boundary and revealed an increasing prominence of the cortical hem, in parallel with increasing numbers of neocortical Reelin/p73 positive CR cells, which attain highest differentiation in the human brain. Our data show that Reelin-expression in the pallium is evolutionarily conserved and independent of a cortical hem, and suggest that p73 in the cortical hem may be involved in the evolutionary increase in number and complexity of the mammalian neocortical CR cells.
authors.affiliation: Departamento de Anatomía, Facultad de Medicina, Universidad de La Laguna, 38071 La Laguna, Tenerife, Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Cabrera-Socorro
authors.forename: Nieves Carolina
authors.initials: NC
authors.lastname: Hernandez-Acosta
authors.forename: Miriam
authors.initials: M
authors.lastname: Gonzalez-Gomez
authors.forename: Gundela
authors.initials: G
authors.lastname: Meyer
mesh_terms: D000818:Animals; D005075:Biological Evolution; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D002540:Cerebral Cortex / Q000196:embryology* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019143:Evolution, Molecular; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008116:Lizards / Q000196:embryology* / Q000378:metabolism*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D010802:Phylogeny; D000091042:Reelin Protein; D012686:Septal Nuclei / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D013687:Telencephalon / Q000196:embryology / Q000378:metabolism; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D004268:DNA-Binding Proteins; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D000091042:Reelin Protein; C000606460:TP73 protein, human; C000606368:Trp73 protein, mouse; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; C000717127:RELN protein, human; C000717128:Reln protein, mouse; D012697:Serine Endopeptidases