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I have investigated the mechanisms by which developmental asymmetry arises, using oocyte determination in Drosophila melanogaster as a model system. The Bicaudal-D (Bic-D) gene is required early in oogenesis for the asymmetric localization of specific mRNAs and proteins and for the differentiation of an oocyte from one of a cluster of 16 interconnected germarial cells. To better understand how Bic-D functions in creating this asymmetry, I took two approaches. First, I examined the role of Bic-D in the asymmetric localization of mRNA and other cellular components during later oogenesis. Second, I molecularly and genetically characterized a gene that interacts with Bic-D in oocyte determination. To determine the role of Bic-D in later oogenesis, I used an inducible source of Bic-D activity to selectively rescue the block at oocyte determination in Bic-D null mutants. Using this system, I find that Bic-D is indeed required in the later stages of oogenesis for the localization of specific mRNAs at both the anterior and posterior of the oocyte. Bic-D is also required for oocyte growth and nuclear positioning, processes which also depend on microtubules. / In the second part of this thesis, I describe the characterization of a Bic-D interacting gene which I have identified as the Drosophila homologue of the human Lissencephaly-1 (Lis-1) gene, DLis-1. Human Lis-1 is the causative gene for Miller-Dieker Syndrome and is required for neuronal migration in the developing brain, while fungal homologues have been implicated in dynein dependent nuclear migration. Like Bic-D , DLis-1 is essential for oocyte determination and for intracellular localization throughout oogenesis. DLis-1 is required for correct positioning of the oocyte nucleus, and appears to function upstream of dynein in this process. Immunolocalization studies suggest that DLis-1 functions as part of a cortical anchor that links microtubules and the oocyte nucleus, via dynein and microtubules, to the cell cortex. DLis-1 and Bic-D are also required for nuclear positioning during neural development in Drosophila, supporting a model in which the neuronal migration defects in Miller-Dieker Syndrome are due to a disruption of dynein/Lis-1 dependent nuclear migration.

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No description available.

Glycosylation is a fundamental post-translational modification of proteins that occurs in all eukaryotes, but the biological significance of specific glycosylation structures is still largely unknown. We have chosen to study this process by cloning and characterizing the genes involved in the N-linked glycosylation pathway in Drosophila melanogaster and analysing mutants of these genes. Since this biochemical pathway for the production of N-linked glycans is considerably conserved, studying it in Drosophila, a useful organism for genetic research, should yield results applicable to other eukaryotes. This thesis describes the attempt to identify a Drosophila homologue of rat ER mannosidase and how this investigation resulted in the identification of a Drosophila cDNA with considerable homology to calnexin, an enzyme involved in the folding of N-glycosylated proteins. It also describes the cloning and characterization of the genomic sequence for the putative Golgi mannosidase II (GmII)* in Drosophila. The expression and control of expression of GmII have been investigated further, and have suggested expression of this gene throughout Drosophila development. Analysis of the GmII promoter region has shown expression from a TATA-less promoter contained within 288bp of sequence 5' to the start of transcription.

Bibliography: p. 75-84. / 84 p., [20] leaves, [36] leaves of plates : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Identifies key interactions between Polycomblike and other members of the Polycomb group and suggests a model for the role of Polycomblike within the group. / Thesis (Ph.D.)--University of Adelaide, Dept. of Genetics, 2000?

Bibliography: p. 75-84. / 84 p., [20] leaves, [36] leaves of plates : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Identifies key interactions between Polycomblike and other members of the Polycomb group and suggests a model for the role of Polycomblike within the group. / Thesis (Ph.D.)--University of Adelaide, Dept. of Genetics, 2000?

Thesis (M.S.)--University of North Carolina at Greensboro, 2007. / Title from PDF t.p. (viewed Mar. 3, 2008). Directed by Vincent C. Henrich; submitted to the Dept. of Biology. Includes bibliographical references (p. 43-46).

Diss. (sammanfattning) Umeå : Univ., 2004. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2005. / Härtill 4 uppsatser.