Project description:Epithelial-mesenchymal interactions are crucial for the development of multiple animal structures. Thus, unraveling how molecular tools are recruited in different lineages to control the interplay between these tissue types is key to understand morphogenetic evolution. Here, we studied Epithelial Splicing Regulatory Protein (Esrp) genes, which regulate extensive alternative splicing programs associated with cell adhesion and motility in human cells and are essential during mouse organogenesis. We found that Esrp genes are involved in the development of many structures in deuterostome organisms, often by conferring epithelial-associated cellular properties. However, this common employment of Esrp in morphogenetic functions was not mirrored at the exon level at the largest phylogenetic distances, as no Esrp-dependent exons appeared conserved between phyla. A remarkable phylum-specific event was observed in the Fgfr gene family, which was recruited as an Esrp target in stem chordates and subsequently co-opted into developmental programs of multiple novel traits in vertebrates.
Project description:Alternative splicing achieves coordinated changes in post-transcriptional gene expression programs through the activities of diverse RNA binding proteins. Epithelial Splicing Regulatory Proteins 1 and 2 (ESRP1 and ESRP2) are cell type-specific regulators of transcripts that switch splicing during the Epithelial Mesenchymal Transition (EMT). To define a comprehensive program of alternative splicing that is regulated during the EMT, we identified an extensive ESRP-regulated splicing network of hundreds of alternative splicing events within numerous genes with roles in cell-cell adhesion, polarity, and migration. Loss of this global ESRP-regulated epithelial splicing program induces the phenotypic changes in cell morphology that are observed during the EMT. Components of this splicing signature provide novel molecular markers that can be used to characterize the EMT. Bioinformatics and experimental approaches revealed a high affinity ESRP binding motif and a predictive RNA map that governs their activity. This work establishes the ESRPs as coordinators of a complex alternative splicing network that adds an important post-transcriptional layer to the changes in gene expression that underlie epithelial-mesenchymal transitions during development and disease. Keywords: control / knockdown comparison and control / ectopic expression comparison
Project description:Tissue- and cell-type specific regulators of alternative splicing (AS) are an essential layer of posttranscriptional gene regulation necessary for normal cellular function, patterning, and development. Here we report the Epithelial splicing regulatory proteins (Esrps) are required for patterning of multiple organs, with loss of both paralogs, Esrp1 and Esrp2, resulting in increasingly severe phenotypes. Global profiling of the Esrp splicing regulatory network from total epidermis revealed varied splicing sensitivity of Esrp targets upon loss of Esrp1 or double knockout. This may explain the progressive phenotypes seen in Esrp knockout mice, and these mice provide a unique genetic tool to evaluate functional consequences of epithelial splicing events in vivo.
Project description:Zebrafish are an important model organism with inherent advantages that have the potential to make zebrafish a widely applied model for the study of energy homeostasis and obesity. The small size of zebrafish allows for assays on embryos to be conducted in a 96- or 384-well plate format, Morpholino and CRISPR based technologies promote ease of genetic manipulation, and drug treatment by bath application is viable. Moreover, zebrafish are ideal for forward genetic screens allowing for novel gene discovery. Given the relative novelty of zebrafish as a model for obesity, it is necessary to develop tools that fully exploit these benefits. Herein, we describe a method to measure energy expenditure in thousands of embryonic zebrafish simultaneously. We have developed a whole animal microplate platform in which we use 96-well plates to isolate individual fish and we assess cumulative NADH2 production using the commercially available cell culture viability reagent alamarBlue. In poikilotherms the relationship between NADH2 production and energy expenditure is tightly linked. This energy expenditure assay creates the potential to rapidly screen pharmacological or genetic manipulations that directly alter energy expenditure or alter the response to an applied drug (e.g. insulin sensitizers).
Project description:Most organisms modulate their reproductive activity responding to day length by the nocturnal release of melatonin by the pineal gland. This hormone is also responsible for synchronizing reproduction with specific external environment stimuli in order to optimize reproductive success.The aim of this study was to establish the effect of melatonin on zebrafish reproduction.Adult females were daily exposed, via water, to two different doses (100 nM and 1 µM) of melatonin. Melatonin led to an increase of the Gonado Somatic Index (GSI) associated with the increase of eggs production, and the raise of gene and protein levels of vitellogenin (VTG) and estradiol receptor ? (ER?) in the liver. The ability of melatonin to increase fecundity was consistent with a significant increase of gene transcription of kiss 1, kiss 2, gnrh3, in the brain, and lh in the pituitary, while in the ovary (in class IIIB follicles), with a significant decrease of two genes codifying for intra-ovarian regulators of premature oocyte maturation, the tgf?1 and the bmp15. The reduction in the expression of these two genes was concomitant with the increase of lhr and a modulation of mpr? and mpr? gene transcription, whose proteins are involved in oocyte maturation. Melatonin also exerted a direct action on follicles as shown by the increase of the oocytes undergoing to germinal vesicle break down (GVBD) and modulated mpr ? and ? gene expression in the in vitro exposure.These data highlight the effects of melatonin in promoting zebrafish reproduction exerting its effects either in the brain-pituitary and in the gonads.