Analysis of Polarity Signaling in Both Early Embryogenesis and Germline Development in C. Elegans: A Dissertation
Authors
Bei, YanxiaFaculty Advisor
Craig C. MelloAcademic Program
Cell BiologyUMass Chan Affiliations
RNA Therapeutics InstituteDocument Type
Doctoral DissertationPublication Date
2005-01-18Keywords
EndodermEmbryo
Proto-Oncogene Proteins
Caenorhabditis elegans
Helminth Proteins
Caenorhabditis elegans Proteins
Cell Division
Germ Cells
Glycogen Synthase Kinase 3
Amino Acids, Peptides, and Proteins
Animal Experimentation and Research
Carbohydrates
Cells
Embryonic Structures
Enzymes and Coenzymes
Macromolecular Substances
Metadata
Show full item recordAbstract
In a 4-cell C. elegans embryo the ventral blastomere EMS requires polarity signaling from its posterior sister cell, P2. This signaling event enables EMS to orient its division spindle along the anterior-posterior (A/P) axis and to specify the endoderm fate of its posterior daughter cell, E. Wnt pathway components have been implicated in mediating P2/EMS signaling. However, no single mutants or various mutant combinations of the Wnt pathway components disrupt EMS polarity completely. Here we describe the identification of a pathway that is defined by two tyrosine kinase related proteins, SRC-1 and MES-1, which function in parallel with Wnt signaling to specify endoderm and to orient the division axis of EMS. We show that SRC-1, a C. elegans homolog of c-Src, functions downstream of MES-1 to specifically enhance phosphotyrosine accumulation at the P2/EMS junction in order to control cell fate and mitotic spindle orientation in both the P2 and EMS cells. In the canonical Wnt pathway, GSK-3 is conserved across species and acts as a negative regulator. However, in C. elegans we find that GSK-3 functions in a positive manner and in parallel with other components in the Wnt pathway to specify endoderm during embryogenesis. In addition, we also show that GSK-3 regulates C. elegans germline development, a function of GSK-3 that is not associated with Wnt signaling. It is required for the differentiation of somatic gonadal cells as well as the regulation of meiotic cell cycle in germ cells. Our results indicate that GSK-3 modulates multiple signaling pathways to regulate both embryogenesis and germline development in C. elegans.DOI
10.13028/z1s6-vy96Permanent Link to this Item
http://hdl.handle.net/20.500.14038/31444Notes
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Copyright is held by the author, with all rights reserved.ae974a485f413a2113503eed53cd6c53
10.13028/z1s6-vy96