The gene capicua is required for the establishment of dorsal-ventral polarity in the Drosophila melanogaster ovary. Loss of capicua function in the follicle cells results in dorsalization of both the embryo and eggshell. The most prominent dorsal features of the Drosophila eggshell are the dorsal appendages. We show that loss of capicua function results in the ventral ectopic specification of dorsal appendage-producing follicle cell fate. This cell fate change is due in part to the ectopic expression of genes such as mirror and Broad-Complex in capicua mutant ovaries. When either mirror or Broad-Complex are ectopically expressed independently of loss of capicua function, they generate a phenotype similar to the capicua mutant phenotype. We propose that Capicua normally acts in the ventral follicle cells to repress the expression of genes that pattern the dorsal follicle cells. EGF receptor signaling may normally inactivate Capicua repression in the dorsal follicle cells.

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 135-152).

No description available.

No description available.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted. Includes bibliographical references.

An organism's immune response may vary due to pathogen pressure in its environment, as well as due to interactions with other organisms. These factors, along with geographic rules (i.e. Gloger's rule) may influence the geographic distribution of the immune response within populations of a species. Here we use real-time quantitative PCR to measure the immune gene expression in six populations collected along the eastern U.S. of Drosophila melanogaster after mating. Antimicrobial genes did not show significant differences in expression due to location, whereas we did observe differences in anti-fungal and pro-phenoloxidase (anti-macromolecule) related genes. These differences in anti-macromolecule resistance are correlated with the latitude of the population opposite of which we would expect by Gloger's rule. We also determined that males and females from different populations tended to drive the differences we detected. Taken together, these results suggest that geographic factors influence genes involved in fungal and macro-pathogens defense post-mating.

No description available.

No description available.

Master of Science / Department of Biology / S. K. Chapes / Ehrlichia chaffeensis is a Gram-negative, obligatorily intracytoplasmic bacterium and the causative agent of a tick-borne disease, human monocytic ehrlichiosis. In vertebrates, E. chaffeensis exhibits tropism for monocytes /macrophages. However, no clear requirements for cell tropism have been defined in ticks. Previously, our group identified two host genes that control E. chaffeensis replication in vivo in Drosophila. We used these two genes, CG6364 and separation anxiety (san) to test the hypothesis that E. chaffeensis replicates in arthropod hemocytes. Using the UAS/GAL4 RNAi system, we generated F1 flies (RNAi flies) and confirmed ubiquitous-or tissue-specific reduction in the transcript levels of the targeted genes. When RNAi flies were screened for Ehrlichia infections, we found that when either CG6364 or san were specifically suppressed in the hemocytes or in the fat body E. chaffeensis failed to replicate or cause infection. Deletion of these genes in the eyes, wings or the salivary glands did not impact fly susceptibility or bacterial replication within these organs. Our data demonstrate that in Drosophila, E. chaffeensis replicates within the hemocytes, the insect homolog of mammalian macrophages, and in the fat body, the liver homolog of mammals. This study provides insights about replication sites of E. chaffeensis in arthropods.