Function and regulation of distal-less-related homeobox genes during visceral arch development in zebrafish.

dc.contributor.advisorEkker, Marc,
dc.contributor.authorEllies, Debra L.
dc.identifier.citationSource: Masters Abstracts International, Volume: 35-01, page: 0164.
dc.description.abstractVertebrate distal-less homeobox genes are known to play a role in embryonic pattern formation. Six zebrafish distal-less homeobox genes have been isolated; dlx1, dlx2, dlx3, dlx4, dlx6, and dlx7. Their combinatorial embryonic expression patterns seen in the forebrain, visceral arches, and fins are suggestive of a new "homeobox code". Various doses of all-trans retinoic acid were used to disrupt distal-less expression during different visceral arch developmental time points. The abnormal visceral arch distal-less expression was further correlated with craniofacial cartilage development. Zebrafish embryos at various stages, treated with 10$\sp{-6}$ M RA, displayed a loss of all distal-less expression in the mandibular and hyoid arches. The embryos exhibiting a loss of distal-less expression, also developed with a loss of mandibular and hyoid arch derived craniofacial cartilage components. Embryos treated with 10$\sp{-7}$M RA displayed a stage dependent loss of distal-less expression, mainly in the branchial arches. The visceral arch craniofacial cartilage differentiated abnormally in embryos displaying a loss of distal-less expression. When distal-less expression was lost in the branchial arches, then only the branchial arch cartilage was lost. However, abnormal distal-less expression in any of the visceral arches could also be correlated with abnormal visceral arch cartilage development. These experiments suggest that dlx genes are part of the multi-step process leading to visceral arch cartilage development. Zebrafish genes involved in this process are sensitive to retinoic acid (10$\sp{-7}$M) until 24hpf, where RA does not seem to affect the process of craniofacial cartilage development. Accordingly, a loss in visceral arch dlx expression during any stage (up to 24hpf) of this process leads to abnormal craniofacial cartilage development. (Abstract shortened by UMI.)
dc.format.extent182 p.
dc.publisherUniversity of Ottawa (Canada)
dc.subject.classificationBiology, Molecular.
dc.titleFunction and regulation of distal-less-related homeobox genes during visceral arch development in zebrafish.
CollectionTh├Ęses, 1910 - 2010 // Theses, 1910 - 2010

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