Project description:To explore the transcriptional effects of aromatase inhibitors on sex differentiation of zebrafish, we exposed 3-month-old zebrafish (AB strain) to the third generation aromatase inhibitor Exemestane (CAS: 107868-30-4) and characterized transcript abundance among testes and ovaries after 32 days of drug exposure. After the drug treatment, we dissected zebrafish gonads, isolated polyA+ RNA and performed high-throughput RNA-Seq analysis.
Project description:The mRNA cap-binding protein eIF4E1b is critical for female germline development in zebrafish. To study the effect of eIF4E1b loss in zebrafish, we isolated gonads with a high expression of ziwi:GFP (female germline marker) from wild-type and eif4e1b mutant juveniles and performed RNA-seq.
Project description:Acute exposure to acrylamide (ACR), a type-2 alkene, may lead to a ataxia, skeletal muscles weakness and numbness of the extremities in exposed human and laboratory animals. Recently, a zebrafish model for ACR neurotoxicity mimicking most of the pathophysiological processes described in mammalian models, was generated in 8 days post-fertilization larvae. In order to better understand the predictive value of the zebrafish larvae model of acute ACR neurotoxicity, in the present manuscript the ACR acute neurotoxicity has been characterized in the brain of adult zebrafish, and the results compared with those obtained with the whole-larvae. Although qualitative and quantitative analysis of the data shows important differences in the ACR effects between the adult brain and the whole-larvae, the overall effects of ACR in adult zebrafish, including a significant decrease in locomotor activity, altered expression of transcriptional markers of proteins involved in synaptic vesicle cycle, presence of ACR-adducts on cysteine residues of some synaptic proteins, and changes in the profile of some neurotransmitter systems, are similar to those described in the larvae. Thus, these results support the suitability of the zebrafish ACR acute neurotoxicity recently developed in larvae for screening of molecules with therapeutic value to treat this toxic neuropathy.
Project description:Sexual development is a process regulated by complex interactions of molecular events that define the final sexual phenotype. Although the genetic and transcriptomic mechanisms involved in the formation of an ovary or a testis are largely studied, the epigenetic mechanisms regulating the fate of an undifferentiated gonad remain poorly understood. Using the zebrafish model (Danio rerio), we exposed larvae of two independent families to high temperature during sex differentiation (18-32 days post fertilization), and by a targeted sequencing approach, we analyzed the methylation profiles of 18 genes related to sexual development in mature gonads two months after the exposure. Gene expression patterns were measured by qPCR in order to correlate them with the DNA methylation. Methylation profiles were family-dependent. However, general patterns of sexual dimorphism were observed in the DNA methylation levels of steroidogenic enzymes (e.g. cyp19a1a, hsd17b1 and hsd11b2), transcription factors (e.g. dmrt1 and amh) and epigenetic-related (dnmt1) genes. In testes, temperature was able to alter the methylation levels of some genes by hypermethylation (cyp19a1a, cyp11a1, amh) or hypomethylation (dmrt1), whereas in ovaries, no changes in the methylation levels were observed. Our results indicate that high temperature during sex differentiation altered methylation in the adult fish gonads and as a novelty, methylation patterns of some genes (e.g., cyp11c1, hsd11b2, dmrt3a and ar) were described here for the fish time in fish.
Project description:The objectives of this study were to characterize gene expression responses to hypoxia in gonads of mature zebrafish (Danio rerio), and to start characterizing modes of action by which hypoxia could potentially alter reproduction. Adult male and female zebrafish were maintained under normoxia (7 mg O2/L), moderate hypoxia (3 mg O2/L) and severe hypoxia (1 mg O2/L) for 4 and 14 days (n = 5 per treatment) and changes in gene expression in gonadal tissues were evaluated using a commercial 21,000 gene zebrafish oligonucleotide microarray. Differentially expressed genes were determined using ANOVA (p < 0.01), and enriched gene ontology (GO) categories (p < 0.05) identified using GeneSpring GX software (Agilent, USA). Short-term (4 d) exposure to hypoxia affected expression of genes associated with the initial adaptive responses such as: metabolism of carbohydrates and proteins, nucleotide metabolism, haemoglobin synthesis, reactive oxygen species metabolism and locomotion. More prolonged (14 d) hypoxia affected a suite of genes belonging to different GO categories: lipid metabolism, reproduction (e.g., steroid hormone synthesis), and immune responses (cytokine synthesis). The results of the present study demonstrate that reproduction likely would be affected by hypoxia via multiple modes of action. These include previously hypothesized mechanisms such as inhibition of steroidogenesis via modulation of expression of steroidogenic genes, and downregulation of serotonergic pathway. But, in addition to these, we propose that there are multiple other points of disruption of reproductive system function linked, for example, to reorganization of lipid transport and other mechanisms involved in responding to hypoxia (e.g., hydroxysteroid dehydrogenase alterations, downregulation of contractile elements etc.). Keywords: time course and dose response