RESUMO
Primary cilia are organelles extended from virtually all cells and are required for the proper regulation of a number of canonical developmental pathways. The role in cortical development of proteins important for ciliary form and function is a relatively understudied area. Here we have taken a genetic approach to define the role in forebrain development of three intraflagellar transport proteins known to be important for primary cilia function. We have genetically ablated Kif3a, Ift88, and Ttc21b in a series of specific spatiotemporal domains. The resulting phenotypes allow us to draw several conclusions. First, we conclude that the Ttc21b cortical phenotype is not due to the activity of Ttc21b within the brain itself. Secondly, some of the most striking phenotypes are from ablations in the neural crest cells and the adjacent surface ectoderm indicating that cilia transduce critical tissue-tissue interactions in the developing embryonic head. Finally, we note striking differences in phenotypes from ablations only one embryonic day apart, indicating very discrete spatiotemporal requirements for these three genes in cortical development.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Transporte Biológico/genética , Cílios/fisiologia , Cinesinas/genética , Prosencéfalo/embriologia , Proteínas Supressoras de Tumor/genética , Animais , Camundongos , Camundongos KnockoutRESUMO
Key facets of mammalian forebrain cortical development include the radial migration of projection neurons and subsequent cellular differentiation into layer-specific subtypes. Inappropriate regulation of these processes can lead to a number of congenital brain defects in both mouse and human, including lissencephaly and intellectual disability. The genes regulating these processes are still not all identified, suggesting genetic analyses will continue to be a powerful tool in mechanistically studying the development of the cerebral cortex. Reelin is a molecule which we have understood to be critical for proper cortical development for many years. The precise mechanism of Reelin, however, is not fully understood. To address both of these unresolved issues, we report here the creation of a novel conditional allele of the Reelin gene and showcase the use of an Etv1-GFP transgenic line highlighting a subpopulation of the cortex: layer V pyramidal neurons. Together, these represent genetic tools which may facilitate the study of cortical development in a number of different ways.
Assuntos
Cerebelo/ultraestrutura , Córtex Cerebral/ultraestrutura , Efeito Fundador , Hipocampo/ultraestrutura , Camundongos Transgênicos , Células Piramidais/ultraestrutura , Alelos , Animais , Moléculas de Adesão Celular Neuronais/genética , Moléculas de Adesão Celular Neuronais/metabolismo , Movimento Celular , Cerebelo/metabolismo , Córtex Cerebral/metabolismo , Cruzamentos Genéticos , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Feminino , Expressão Gênica , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Hipocampo/metabolismo , Masculino , Camundongos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Plasmídeos/química , Plasmídeos/metabolismo , Células Piramidais/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteína Reelina , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , TransfecçãoRESUMO
Grainyhead-like genes are part of a highly conserved gene family that play a number of roles in ectoderm development and maintenance in mammals. Here we identify a novel allele of Grhl2, cleft-face 3 (clft3), in a mouse line recovered from an ENU mutagenesis screen for organogenesis defects. Homozygous clft3 mutants have a number of phenotypes in common with other alleles of Grhl2. We note a significant effect of genetic background on the clft3 phenotype. One of these is a reduction in size of the telencephalon where we find abnormal patterns of neural progenitor mitosis and apoptosis in mutant brains. Interestingly, Grhl2 is not expressed in the developing forebrain, suggesting this is a survival factor for neural progenitors exerting a paracrine effect on the neural tissue from the overlying ectoderm where Grhl2 is highly expressed. genesis 53:573-582, 2015. © 2015 Wiley Periodicals, Inc.
RESUMO
Phenotype-driven mutagenesis experiments are a powerful approach to identifying novel alleles in a variety of contexts. The traditional disadvantage of this approach has been the subsequent task of identifying the affected locus in the mutants of interest. Recent advances in bioinformatics and sequencing have reduced the burden of cloning these ENU mutants. Here we report our experience with an ENU mutagenesis experiment and the rapid identification of a mutation in a previously known gene. A combination of mapping the mutation with a high-density SNP panel and a candidate gene approach has identified a mutation in collagen type II, alpha I (Col2a1). Col2a1 has previously been studied in the mouse and our mutant phenotype closely resembles mutations made in the Col2a1 locus.
