Project description:Tdp1, tyrosyl-DNA phosphodiesterase 1, is an enzyme responsible for the repair of DNA breaks resulting from aberrant topoisomerase 1 activity, called Top1 cleavage complexes (Top1-CCs). Mutation of Tdp1 leads to a progressive neurodegenerative disorder spinocerebellar ataxia with axonal neuropathy 1 (SCAN1). We have generated tdp1-/- zebrafish as a model for SCAN1. The adult fish have a behavioral defect and hypersensitivity to camptothecin (CPT), a Top1 poison. Strikingly, the embryos do not show increased sensitivity to CPT, unlike any other reported vertebrate models, suggesting genetic compensation is at play at this stage. We thus carried out microarray analysis in CPT-treated zebrafish embryos to compare the gene expression profiles of tdp1WT and tdp1-/- genotypes. Gene expression analysis revealed 1,8111 genes that were differentially expressed: 1,071 were upregulated and 740 were downregulated. Sprtn and neil1, two potential compensation candidates were upregulated in the tdp1-/- embryos.
Project description:TDP1 is an enzyme that in humans is encoded by the TDP1 gene.[5][6][7] TDP1 is the protein involved in repairing stalled topoisomerase I-DNA complexes. We evaluated the effect of Tdp1 knockout in HEK293A cells on the gene expression.
Project description:Spinocerebellar ataxia with axonal neuropathy (SCAN1) is a rare recessive neurodegenerative syndrome associated with cerebellar atrophy and peripheral neuropathy. It is caused by a homozygous missense mutation in the tyrosyl-DNA phosphodiesterase-1 (TDP1) gene (A1478G). resulting in a substitution of histidine for arginine-493 (H493R) in the TDP1 catalytic site, leading to reduced TDP1 activity. How TDP1 H493R mutation promotes the SCAN1 phenotype, which is associated with the death of post-mitotic neurons, is unclear. We have generated models of osteosarcoma U2OS cells homozygous for TDP1 H493R employing the CRISPR-Cas9 technique (2 clones, named “1P” and “3.3”). Here, we have generated transcriptional genome wide profile in order to characterize differences in gene expression that are specific of TDP1-mutated clones.
Project description:Zebrafish (Danio rerio) model system have used widespread vertebrate investigations for genetic and cell biological analyses, and is suitable for small molecular screens such as chemical, toxicity and drug in order to use for human diseases and drug discovery . Recently, These powerful zebrafish model increasingly apply to human metabolic disease such as obesity and diabetes and toxicology. Despite a lot of advantages, proteomics research at zebrafish has received little interest in comparison with genetic and biological research using histology and in situ hybridization. Protein lysine acetylation is one of the most known post-translational modifications with dynamic and reversibly controlled by lysine acetyltransferase such as histone acetyltransferases and lysine deacetylase such as histone deacetylases and sirtuins family.Also, during the past year, global lysine acetylome studies using MS-based proteomics approach was in diverse species such as human, mouse, E. coli, Yeast and plants. Based on global acetylome data, our understanding of the roles of lysine acetylation in various cellular processes has increased. . The aim of this study was to identify Lysine acetylation in zebrafish embryos and determine the homology from Human at modified site level. Here we showed the global lysine acetylation study in Zebrafish embryos using MS-based zebrafish embryos.
Project description:Investigation of whole genome gene expression level changes in zebrafish TIF1g-deficient, cdc73 deficient and double-deficient embryos, compared to the wild-type ebryos.
Project description:TDP1 removes transcription-blocking TOP1 cleavage complexes (TOP1ccs) and its inactivating H493R mutation causes the neurodegenerative syndrome SCAN1. However, the molecular mechanism underlying SCAN1 phenotype is unclear. Here, we generate human SCAN1 cell models using CRISPR/Cas9 and show that they accumulate TOP1ccs along with changes in gene expression and genomic distribution of R-loops. SCAN1 cells also accumulate transcriptional DNA double-strand breaks (DSBs) specifically in the G1 cell population due to increased DSB formation and lack of repair, both resulting from abortive removal of transcription-blocking TOP1ccs. Deficient TDP1 activity causes increased DSB production and the presence of mutated TDP1 protein hampers DSB repair by a TDP2-dependent back-up pathway. This study provides powerful models to study TDP1 functions under physiological and pathological conditions and unravels that a gain of function of the mutated TDP1 protein, which prevents DSB repair, rather than a loss of TDP1 activity itself, could contribute to SCAN1 pathogenesis.