Project description:Mutation or deletion of LIS1 (Lissencephaly-1) underlies classical lissencephaly, a migration disorder resulting in brain malformation, epilepsy and mental retardation. Orthologues for LIS1 genes (lis1a and lis1b) are ubiquitously expressed in developing zebrafish larvae, but the functional consequences of Lis1 knockdown are unknown. Here we used lis1-specific morpholino oligonucleotides (MOs, targeting protein translation or mRNA splicing, respectively) to transiently knockdown Lis1 expression in zebrafish. Injection of lis1 MOs resulted in morphological changes including microcephaly. At four days post-fertilization, lis1 morphants exhibited spontaneous convulsive behavior and abnormal large-amplitude electrographic discharge resembling that seen in acute and genetic zebrafish models of epilepsy. Abnormal brain development and neuronal migration defects were observed when lis1 MO injections were made into fluorescent reporter lines demarcating interneuron distribution (Dlx5a/6a:GFP) and brain structure (GBT0133:mRFP). Microarray analysis for ~44,000 Danio rerio transcripts identified 215 up-regulated and 160 down-regulated genes. Quantitative PCR and whole-mount in situ hybridization were used to validate these results for twenty and seven genes, respectively. These findings in a simple vertebrate model reproducing neuroanatomical and epileptic hallmarks of the human condition represent a novel approach to the study of childhood seizure disorders associated with a single gene mutation 4 WT samples (sample= 10 pooled larvae) and 4 Lis1Morphants slight phenotype (sample= 10 pooled larvae) were collected at 4dpf (days post fertilization). The morphants were selected based on phenotype and seizure behavior. Both groups of fish derived from same pools of eggs
Project description:Proper cortical development relies on the balance of neuronal migration and proliferation. We investigated the gene expression differences of mouse knock-outs for Lissencephaly in humans. Our analysis suggests that gene expression and pathway analysis in mouse models of a similar disorder or within a common pathway can be used to define novel candidates for related human diseases. We investigated the developing brain of four mutants and wild-type mice using expression microarrays, bioinformatic analyses, and in vivo/in vitro experiments to address whether mutations in different members of the LIS1 neuronal migration complex lead to similar and/or distinct global gene expression alterations.
Project description:Mutation or deletion of LIS1 (Lissencephaly-1) underlies classical lissencephaly, a migration disorder resulting in brain malformation, epilepsy and mental retardation. Orthologues for LIS1 genes (lis1a and lis1b) are ubiquitously expressed in developing zebrafish larvae, but the functional consequences of Lis1 knockdown are unknown. Here we used lis1-specific morpholino oligonucleotides (MOs, targeting protein translation or mRNA splicing, respectively) to transiently knockdown Lis1 expression in zebrafish. Injection of lis1 MOs resulted in morphological changes including microcephaly. At four days post-fertilization, lis1 morphants exhibited spontaneous convulsive behavior and abnormal large-amplitude electrographic discharge resembling that seen in acute and genetic zebrafish models of epilepsy. Abnormal brain development and neuronal migration defects were observed when lis1 MO injections were made into fluorescent reporter lines demarcating interneuron distribution (Dlx5a/6a:GFP) and brain structure (GBT0133:mRFP). Microarray analysis for ~44,000 Danio rerio transcripts identified 215 up-regulated and 160 down-regulated genes. Quantitative PCR and whole-mount in situ hybridization were used to validate these results for twenty and seven genes, respectively. These findings in a simple vertebrate model reproducing neuroanatomical and epileptic hallmarks of the human condition represent a novel approach to the study of childhood seizure disorders associated with a single gene mutation