Characterizing Regulators of the C. elegans Cytoskeleton
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2014-10-30
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Abstract
Understanding the process of embryonic morphogenesis is one of the most important questions in developmental biology. Morphogenesis is an important process that allows an organism to develop its final body shape. In most organisms, embryos form a roughly spherical ball of cells, but its final shape requires precise morphogenic and molecular events that have several layers of regulation. In Caenorhabditis elegans, a smooth muscle-like contraction of an actin/myosin network in the epidermis mediates the elongation of a worm embryo from a ball of cells into a long, thin worm. In this system only the lateral epidermal cells contract, suggesting that a localized Rho GEF (guanine exchange factor), which is an activator of contraction, is involved in this process.
The first project of this thesis focused on characterizing a previously identified Rho GEF encoded by RHo Guanine nucleotide exchange Factor 2 (rhgf-2) gene. Previous work has placed rhgf-2within the context of a genetic pathway, but further characterization during early embryogenesis has not been studied. I continued the characterization of RHGF-2 by determining its protein expression pattern during embryogenesis and found that although it is ubiquitously expressed, RHGF-2 expression in the lateral epidermal cells is both necessary and sufficient for morphogenesis. The maternal and zygotic expression of RHGF-2 was also determined. I found that maternal expression regulates the speed of cleavage furrows in the early embryo while zygotic expression mediates morphogenesis. Finally, I examined the actin dynamics and tissue specific activity of RHGF-2.
A second project focused on identifying a new component of the elongation pathway. A suppressor screen performed by a previous lab member against a mel-11 elongation-defective mutant discovered many components of the embryonic elongation pathway as we know it today. However, one allele of an unknown gene that our lab has designated as sb89 was not identified. I identified the gene represented by the sb89 mutation as ZK185.1 by using a combination of traditional mapping techniques in combination with Whole Genome Sequencing (WGS).
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Chan, B. G. (2014). Characterizing Regulators of the C. elegans Cytoskeleton (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25301