Danio rerio
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA329125 | ENA |
REPOSITORIES: ENA
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Project description:The aryl hydrocarbon receptor (AHR) repressor (AHRR), a bHLH-PAS protein, is a transcriptional repressor of AHR and other transcription factors (HIF, ER) and is regulated by an AHR-dependent mechanism. However, the physiological and toxicological roles of AHRR are not well understood. We demonstrated earlier that knockdown of AHRRa (one of two AHRR paralogs) in zebrafish embryos using morpholino anti-sense oligonucleotides results in developmental phenotypes such as pericardial edema, craniofacial malformations, and cardiac deformities, similar to effects caused by exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). AHRRa morphants also exhibit down-regulation of genes associated with photoreceptor development. To characterize the AHRRa function further, we used ZFN (zinc finger nuclease) technology to generate a line of zebrafish with a 7-bp deletion in exon 3 of AHRRa, leading to a truncated AHRR (110 aa, of which 38 are from AHRRa, compared to the 550-aa wild-type (wt) AHRRa). The mutant AHRRa protein, which contains basic regions but lacks the HLH and PAS domains, did not repress AHR in vitro, suggesting that it is inactive (null). Unlike AHRRa morphants, AHRRa-null fish did not display a TCDD-like phenotype; exposure to TCDD caused defects similar to those in TCDD-exposed wt embryos. RNA-sequencing revealed that basal expression of 562 genes differed significantly between the null and wt embryos, including down-regulation of genes associated with photoreceptor development, as seen in AHRRa morphants. TCDD-induced gene expression patterns for the prototypic AHR target genes were similar for null and wt embryos. However, 22 genes were differentially regulated by TCDD in the AHRRa-null embryos as compared to wt embryos (>2-fold; 5% FDR). We are currently investigating the link between these differentially expressed genes and the function of AHRRa in development and AHR signaling. [Supported by NIH R01ES006272]
2017-12-31 | GSE84420 | GEO
Project description:AHR Activation by TCDD Downregulates Sox9b Expression Producing Jaw Malformation in Zebrafish Embryos
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Project description:MicroRNA expression profiling after short-term exposure to TCDD in zebrafish embryos [miRNA-Seq data]
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Project description:AB* zebrafish embryos exposed to 1 ng/mL TCDD from 1d to 5d post-fertilization.
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Project description:MicroRNA expression profiling after short-term exposure to TCDD in zebrafish embryos [agilent and exiqon array data]
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Project description:Transcriptome analysis of 6 hours post fertilization mecp2-null versus wild type zebrafish embryos
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Project description:Altered gene expression in zebrafish embryos exposed to tert-butylhydroquinone and 2,3,7,8-tetrachlorodibenzo-p-dioxin
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Project description:Transcriptomic analyses of TCDD treated zebrafish liver
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Project description:Purpose:To investigate the transcriptomic profiles in zebrafish embryos exposed externally to nucleotides at a critical develpomental window (3-7 days post fertilization) determine biological processes and pathways based on differentially expressed gene transcripts using High Throughput Sequencing (HTS). Methods:Total mRNA profiles of 7 dpf zebraifsh embryos after exposure to 10-5M ATP, AMP, adenosine and adenine were generated by deep sequencing, in triplicate, using Illumina HiSeq2500 Results: There were many differentially expressed genes; including ubiquitin-, actin-, and tubulin-related, showing that the cytoskeleton was altered; other DEGs involved with purine binding, specifically guanine, which was expected as the mixture was composed of purines; DEGs involved with GTP binding were also upregulated, suggesting increased cell signaling,
2020-03-23 | GSE97016 | GEO
Project description:Polychlorinated biphenyls (PCBs) are persistent and ubiquitously distributed environmental pollutants. Based on their chemical structure, PCBs are classified into non-ortho substituted and ortho-substituted congeners. Non-ortho-substituted PCBs are structurally similar to dioxin or TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and their mode of action and toxic effects are well established. In contrast, much less is known about the effects of ortho-substituted PCBs. Studies conducted so far have focused on tissue-specific effects but there is limited knowledge about the effects on the whole organism, particularly the sensitive developmental stages in vertebrates. Hence, in this study we investigated the effects of exposure to an environmentally relevant ortho-substituted PCB (2,2’,4,4’,5,5’-hexachlorobiphenyl; PCB153) on zebrafish embryos. We exposed zebrafish embryos to either DMSO (0.1%; solvent control) or three different concentrations of PCB153 (0.1, 1 and 10 μM) from 4 hours post-fertilization (hpf) to 120 hpf. At the end of the exposure, larvae were sampled for determining transcriptional changes (RNA sequencing) and the remaining embryos were maintained in contaminant-free environment. At 7 and 14 days post-fertilization (dpf), zebrafish larvae were assessed for locomotory behavior. We did not observe any overt phenotypes during the exposure period, but observed a spinal phenotype in the 10μM PCB153 treated group starting at 7 dpf. This phenotype was observed in a dose-dependent manner and majority of the embryos with this phenotype died by 14 dpf. RNA sequencing of 5 dpf larvae exposed to PCB153 also revealed dose-dependent changes in gene expression patterns. A total of 633, 2227, and 3378 differentially expressed genes were observed in 0.1, 1 and 10 μM PCB153 treated embryos, respectively. Among these, 301 genes were common to all treatment groups, and KEGG pathway analysis revealed enrichment of genes related to circadian rhythm, FOXO signaling and insulin resistance pathways. We are currently investigating the functions of genes that are uniquely altered by different PCB153 concentrations. Overall, these results suggest that developmental exposure to PCB153, a PCB congener highly prevalent in the environment, targets multiple physiological processes including photoperiod regulation and metabolism. [Funded by NIH P01ES021923 and NSF OCE-1314642].
2017-12-31 | GSE93310 | GEO