Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2007. / Härtill 3 uppsatser.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 138-170).

The proteins and molecular machinery mediating the release of cortical granule (CG) contents from fertilized embryos is not completely understood. The process of vesicle fusion involves linking chaperones prior to vesicle to membrane contact. Rab3A, a member of a low-molecular weight GTP-binding protein superfamily has been detected in mouse embryos from the unfertilized meiotic II stage to the 2-cell. It is believed to positively regulate the final step of CG exocytosis by binding to Rabphillin, calcium ions (Ca2+), and phospholipids. SNAP23 a member of soluble NSF [N-ethylmaleimidesensitive factor] attachment protein receptors (SNAREs) binds together with parts of the Rab3A-rabphilin3A complex and is believed to be involved in the Ca2+-dependent exocytosis of non-neuronal systems. In this study we observed the mRNA expression for SNAP23 and Rab3A in pre-Meiotic I, post-Meiotic I unfertilized eggs (pre-MI UFE and post-MI UFE), and fertilized eggs (FE) utilizing RT-PCR. The products were analyzed in 2% agarose gel stained with ethidium bromide. Density analysis using a globin external standard showed that the levels of mRNA transcripts declined from the UFE to the FE in both genes, SNAP23 and Rab3A. Immunofluorescence was used for the detection and localization of Rab3A protein within the pre-MI and post-MI UFE and FE mouse egg. Eggs were stained with anti-Rab3A primary antibody and lens culinaris agglutinin (LCA) conjugated to FITC. Rab3A showed punctate staining in pre- and post-MI UFEs on small vesicles assumed to be CGs and in FEs on vesicles of a larger size. Uniform cytoplasmic expression was also seen, throughout the cells cortical and subcortical regions in each stage (pre- and post-MI UFEs and FEs), but with decreasing intensity as the eggs matured. This cytoplasmic stain may represent inactive Rab3A in the cytosol. The LCA stain showed punctate expression of cortical granules with localization within the cortical region and the plasma membrane. The addition of information on SNAP23 and Rab3A will aid in the process of studying CG exocytosis as well as in understanding the temporal and spatial development pathways involved in stimulating the cortical reaction. / Department of Biology

Thesis (Ph.D.). / Written for the Dept. of Biology. Title from title page of PDF (viewed 2008/07/24). Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri--Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 107-112). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri--Columbia, 2000. / "August 2000." Typescript. Vita. Includes bibliographical references (leaves 107-112). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. Includes bibliographical references.

Thesis (Ph.D.)--University of Alberta, 2010. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Medical Microbiology and Immunology. Title from pdf file main screen (viewed on April 24, 2010). Includes bibliographical references.

As we age, our ability to cope with a variety of stresses significantly decreases. One of the features of an ageing organism is the dramatic increase in the number of cells arrested in the G1 phase, a process known as senescence. It is well established that the senescence phenotype leads to a change in the way cells respond to stress. However, the molecular mechanisms by which these cells cope and/or respond to a variety of environmental challenges remain unknown. In general, cells respond to stress by engaging a variety of mechanisms; one of them is the assembly of cytoplasmic foci known as stress granules (SGs). These entities are considered as part of the survival pathways that are activated at the beginning of any stress to protect key cellular elements which allow a quick recovery if the stress is rapidly removed. However, we do not know whether SGs formation is activated during senescence. In this study, we investigated the formation and the role of SGs in senescent cells exposed to various stresses. We demonstrated that while SGs can assemble in response to oxidative stress (OS) during all the steps leading to senescence activation, their number significantly increases at late stage of senescence. This increase correlates with a rapid decrease in the expression of the cyclin kinase inhibitor p21, one of the main players in the activation of the senescence phenotype. Although the OS-induced recruitment of p21 mRNA to SGs correlates with a significant increase in its half-life, this translocation interferes with p21 translation only at late senescence. This translation inhibition could be explained by the co-recruitment of CUGBP1, a known translation activator during senescence of p21, and p21 mRNA to SGs. Therefore, our data suggest that SGs formation and the reduction in p21 protein levels represent two main events through which senescent cells respond to stress conditions.

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