Dataset Information

MicroRNA profiling in Atlantic killifish (Fundulus heteroclitus)

ABSTRACT: The Atlantic killifish (Fundulus heteroclitus) is an ideal model species to study physiological and toxicological adaptations to stressors. Killifish inhabiting the PCB-contaminated Superfund site in New Bedford Harbor, MA (NBH) have evolved resistance to toxicity and activation of the aryl hydrocarbon receptor (AHR) signaling pathway after exposure to PCBs and other AHR agonists. Until recently, a lack of genomic information has limited efforts to understand the molecular mechanisms underlying environmental adaptation to stressors. The advent of high throughput sequencing has facilitated an unbiased assessment of coding as well as non-coding RNAs in any species of interest. Among non-coding RNAs, microRNAs (miRNAs) are important regulators of gene expression and play crucial roles in development and physiology. The objective of this study is to catalog the miRNAs in killifish and determine their expression patterns in the embryos from contaminated (NBH) and pristine (Scorton Creek, MA (SC)) sites. Embryos from NBH and SC were collected daily from 1 to 15 days post-fertilization and RNA from pooled samples from each site was sequenced using SOLiD sequencing. We obtained 7.5 and 11 million raw reads from pooled SC and NBH samples, respectively. Analysis of the sequencing data identified 216 conserved mature miRNA sequences that are expressed during development. Using the draft killifish genome, we retrieved the miRNA precursor sequences. Based on the capacity of these putative precursor sequences to form the characteristic hairpin loop (assessed using RNAfold), we identified 197 conserved miRNA sequences in the genome.

ORGANISM(S): Fundulus heteroclitus

PROVIDER: GSE70953 | GEO | 2015/07/20

SECONDARY ACCESSION(S): PRJNA290009

REPOSITORIES: GEO

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Project description:This study presents statistical analyses of gene expression in 5, 10 and 15 day post-fertilization (dpf) embryos of the teleost Fundulus heteroclitus treated with control vehicle (DMSO) or a potent non-ortho-PCB (PCB-126; 3,3’,4,4’,5-pentachlorobiphenyl). The embryos were from two populations: a clean, reference population (SC, Scorton Creek, MA USA) and a polluted Superfund population (N, New Bedford Harbor, MA USA). For each site, eggs from 8 females (~1100 total) were fertilized using minced testes from 5 males. After non-fertile eggs were culled, embryos were exposed to vehicle (DMSO; 0.1%) or PCB-126 (50 nM) in filtered seawater (salinity 25 part per thousand, 65 embros per 20 ml in glass petri dish) for 4 hr at 20º C. After exposure, the embryos were washed in filtered seawater and incubated at 20º C under a 14-h light, 10-h dark cycle. At 5-, 10-, and 15-dpf, embryos were collected as three pools of 20 embryos from each treatment group and flash frozen in liquid nitrogen and stored at -80º C until used for RNA isolation. A loop design was used for the microarray hybridizations where each sample is hybridized to 2 arrays using both Cy3 and Cy5 labeled fluorophores. We used three loops in which each loop consisted of Cy3- and Cy5-labeled embryo aRNAs from 12 samples: one sample from each population-treatment-time combination. Within a population-treatment-time, embryos were randomly assigned to one of the three loops. In total, 36 embryos were hybridized to 36 microarrays. The loops formed were SC5C→ SC5P → NBH5C→ NBH5P →SC10C→ SC10P→ NBH10C→ NBH10P → SC15C→ SC15P → NBH15C → NBH15P → SC5C, where each arrow represents a separate hybridization (array) with the biological sample at the base of the arrow labeled with Cy3 and the biological sample at the head of the arrow labeled with Cy5. SC represents the Scorton Creek, Sandwich, MA population (reference), NBH represents the New Bedford Harbor, MA population, C represents control dose (DMSO), P represents the PCB-126 dose, 5 represents 5 dpf, 10 represents 10 dpf and 15 represents 15 dpf.

Dataset Information

MicroRNA profiling in Atlantic killifish (Fundulus heteroclitus)

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