Project description:We evaluate the global gene expression changes that occur during a stage-matched developmental window in a closely related set of killifish species.
Project description:We evaluate the global chromatin changes that occur during the developmental progression and development-to-diapause transition in a closely related set of killifish species.
Project description:The RNA-seq data contain 3 tissues (brain, liver, skin) of N. furzeri strains MZM-0410 and GRZ plus 2 biological replicates of brain of 6 other killifish species. Jena Centre for Systems Biology of Ageing - JenAge (www.jenage.de)
Project description:The mangrove killifish, Kryptolebias marmoratus, can reproduce with self-fertilisation, offering a unique and useful genetic tool for generation of genetic mutants and quick identification of mutated genes. From an ENU-mutated mangrove killifish line R228, we have isolated a novel mutant line, no-fin-ray/nfr in which homozygous mutant of adult fish fin ray development is largely reduced. Besides the reduction of the fin, the nfr mutant also exhibited other phenotype associated with ectodermal cell lineages including loss of scales, deformation in the gill structure such as decreasing the number of gill filaments, the reduction in the number of jaw teeth, pharyngeal teeth and gill rakers. Illumina RNAseq with 3 embryos each from mutants, siblings and the parental WT strain Hon9 (only 9 embryos as total) identified a mutation in the edaradd in a highly conserved C-terminal death domain. Edaradd is known as a cytoplasmic accessory protein for the Ectodysplasin A (EDA) signalling pathway. To confirm the crucial role of edaradd during fin development, CRISPR RNAs were designed to knock out the gene in another killifish species, Arabian killifish. Indeed, Arabian killifish edaradd crispants showed a potent reduction of the fin development with 100% frequency. Furthermore, EDA crispants also showed identical phenotypes to that of edaradd crispants, confirming the fin defect in the mutants/crispants is caused by the signalling pathway of the EDA in the killifish species. These data demonstrate a powerful genetic approach using isogenic self-fertilising mangrove killifish as a tool for identifying mutants and their mutation, and revealed the crucial role of edaradd for the first time in the fish fin development and other ectoderm derived epithelial tissues.
Project description:Diapause is a reversible developmental arrest faced by many organisms in harsh environments. Annual killifish present this mechanism in three possible stages of development. Killifish are freshwater teleosts from Africa and America that live in ephemeral ponds, which dry up in the dry season. The juvenile and adult populations die, and the embryos remain buried in the bottom mud until the next rainy season. Thus, species survival is entirely embryo-dependent, and they are perhaps the most remarkable extremophile organisms among vertebrates. The aim of the present study was to gather information about embryonic diapauses with the use of a “shotgun” proteomics approach in diapause III and prehatching Austrolebias charrua embryos. Our results provide insight into the molecular mechanisms of diapause III. We detected a diapause-dependent change in a large group of proteins involved in different functions, such as metabolic pathways and stress tolerance, as well as proteins related to DNA repair and epigenetic modifications. Furthermore, we observed a diapauseassociated switch in cytoskeletal proteins. This first glance into global protein expression differences between prehatching and diapause III could provide clues regarding the induction/maintenance of this developmental arrest in A. charrua embryos. There appears to be no single mechanism underlying diapause and the present data expand our knowledge of the molecular basis of diapause regulation. This information will be useful for future comparative approaches among different diapauses in annual killifish and/or other organisms that experience developmental arrest.
Project description: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.