Investigation of genetic compensation in tdp1-/- zebrafish embryos
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ABSTRACT:
PROVIDER: PRJNA626551 | ENA |
REPOSITORIES: ENA
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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.
2022-04-19 | GSE148923 | GEO
Project description:Investigation of genetic compensation in tdp1-/- zebrafish embryos
| PRJNA626551 | ENA
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.
2023-11-20 | GSE247361 | GEO
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.
2024-04-30 | GSE186693 | GEO
Project description:Studying X-chromosome dosage compensation dynamics in human early embryos using single cell RNA sequencing
2019-10-24 | GSE130050 | GEO
Project description:A phenomenon of genetic compensation is commonly observed when an organism with a disease-bearing mutation does not show phenotypic penetrance due to compensatory gene expression changes. Reports have spread showing the absence of disease phenotypes in stable knockout models, but not in transient knockdown models. As such, these incidents present a challenge for the disease modeling field, although a deeper understanding of genetic compensation may also hold the key for novel therapeutic interventions. In our study we created a knockout model of slc25a46 gene, which is a recently discovered important player in mitochondrial dynamics and deleterious mutations in which are known to cause peripheral neuropathy, optic atrophy and cerebellar ataxia. We report a case of genetic compensation in the fourth generation (F4) of slc25a46 knockout zebrafish mutant, in contrast to a penetrant disease phenotype in the first generation (F0) slc25a46 mosaic mutant (crispant), generated with CRISPR/Cas-9 technology. We show that F0 crispant phenotype is specific and rescuable. By performing mRNA sequencing, we define significant changes in slc25a46 F4 mutant’s gene expression profile, which are nearly not present in F0 crispants. We find that among the top candidates for the phenotypic compensation anxa6 gene stands out as a functionally relevant player in mitochondrial dynamics. We also find that our genetic compensation case does not arise from previously identified mechanisms driven by mutant mRNA decay. Our study serves as an important contribution to the understanding of phenomenon of genetic compensation and presents novel insights on Slc25a46 function. Furthermore, our study provides the evidence for the efficiency of F0 CRISPR screens for disease candidate genes, which may advance the field of functional genetics.
2019-10-04 | GSE138414 | GEO
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.
2024-04-25 | GSE226263 | GEO
Project description:X-chromosome dosage compensation dynamics in human early embryos
| PRJNA533639 | ENA
Project description:Genetic compensation in a stable slc25a46 mutant zebrafish
| PRJNA575769 | ENA
Project description:Sex determination is still poorly understood in birds and no key determinants have so far been identified. In contrast to most other species, dosage compensation of bird sex chromosomal genes appears rather ineffective. By comparing microarrays of microdissected primitive streak from single chicken embryos, we identified a large number of genes differentially expressed between male and female embryos at a very early stage (Hamburger and Hamilton stage 4), long before any sexual differentiation occurs. Most of these genes are located on the Z chromosome, which indicates that dosage compensation is ineffective in early chicken embryos. Gene ontology analyses using an enhanced annotation tool for Affymetrix probesets of the chicken genome shows that among the male-biased genes found on the Z chromosome, more than 20 genes have a role in sex differentiation.
2009-05-13 | GSE16064 | GEO