The exoskeleton of the fins comprises fin rays and actinotrichia; the latter are small unmineralized fibrils found at the distal margin of fin rays. Actinotrichia play a role in the growth and structure of the fins during fin development and regeneration. Our lab has previously identified the actinodin (and) gene family, which codes for structural proteins in actinotrichia. Interestingly, the loss of this gene family has been proposed to be involved in the loss of fin rays, an important step in the fin-to-limb transition during evolution. Furthermore, the and genes are expressed in the epithelial cells and in the migrating mesenchymal cells of the zebrafish embryonic pectoral and median fin fold. The presence of tissue-specific cis-acting regulatory elements were found within the 2 kilobase pair genomic region (2P) located upstream of and1’s first untranslated exon by performing analyses of the expression of a fluorescent reporter (EGFP) placed under the control of fragments of various lengths originating from the 2P genomic fragment in zebrafish transgenic lines. Using these various and1 reporter lines, tissue-specific and1 expression was previously characterized during the embryonic stage of zebrafish development. However, these transgenic reporter lines were not analyzed throughout important fin morphogenesis events occurring during fin development, such as the initial formation of lepidotrichia and the resorption of the median fin fold, and throughout fin regeneration as well.
This study mainly enabled us to characterize in great details and1 expression throughout fin development and regeneration using the various tissue-specific and1 reporter lines by performing time course analyses. In doing so, we were able to demonstrate that these reporter lines recapitulate endogenous and1 expression through in iii situ hybridization and RT-PCR experiments. Furthermore, the distinct transgene expression patterns observed during lepidotrichia formation/regeneration in the various and1 reporter lines supports previous research that proposes and1-expressing cells may indirectly contribute to lepidotrichia formation not only during fin regeneration but during fin development as well. Furthermore, the characterization of the tissue-specific and1 reporter lines throughout development allowed us to characterize specific changes in the cis-acting regulation of and1 in the fins of adult fish when compared with the tissue-specific and1 reporter expression patterns characterized during the embryonic stage. All in all, this study provides further clues on the contribution of and1-expressing cells throughout fin development and regeneration.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/36080 |
| Date | January 2017 |
| Creators | Northorp, Marissa |
| Contributors | Akimenko, Marie-Andree |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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