Thesis (M. Med. Sc.)--University of Hong Kong, 2005.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Cartilaginous fish are the most ancient lineage to possess an adaptive immune system however nothing is known about the processes involved in the development, maintenance or proliferation of B cells in this group. In this thesis studies were undertaken to explore whether transcription factors, cytokines and cell surface markers that are involved in B cell immune responses in mammals are also present in cartilaginous fish. Through sequence database mining forty-one genes involved in B cell immune biology were found; of these twelve were B cell transcription factors. The presence of important B cell transcription factors, such as EBF1, pax5, E2A, Blimp1, PU.1 and Bcl6 suggests that B cells in cartilaginous fish probably undergo a similar developmental pathway as those in mammals. Eight cytokines, eleven cytokine receptors and four B cell surface markers were also identified, including CD40L, BAFF and CD79α that were further studied in this thesis. I cloned CD40L and BAFF from cartilaginous fish, both members of the tumour necrosis factor family and found cartilaginous fish BAFF genes have an extra exon that forms a unique α-helix insertion, and which may impact on receptor binding. The importance of all three molecules for the adaptive immune response was indicated by relatively high expression in shark immune tissue, such as spleen, gut-associated lymphoid tissue, gill and the Leydig organ, and the fact that their expression could be induced by immunostimulants, such as pokeweed mitogen. The finding that CD79α expression significantly correlates with those of immunoglobulin heavy-chains and the co-expression of CD79α and IgM on the B cell surface indicate that as in mammals CD79α in cartilaginous fish is expressed by B cells and associates with surface-bound immunoglobulin to form the active B cell receptor. Thus CD79α may serve as a pan B cell marker in future immunological studies in cartilaginous fish.

Interest in the mechanisms of homeo domain specificity led to a screen that identified Drosophila proteins able to bind a consensus homeo domain site. One clone isolated in this screen produced no homeo domain and was selected for further characterisation as a protein with an unknown DNA binding domain and the potential to interact with homeo domain proteins on the DNA. This thesis describes the characterisation of the Drosophila gene dead ringer ( dri ) corresponding to this clone. Isolation of overlapping cDNA clones and sequence analysis allowed the identification of a complete open reading frame in the dri message that gave a predicted protein of 901 amino acids. Database searches and multiple sequence alignment revealed a widely conserved motif in the Dri sequence that is found in proteins from organisms as diverse as yeast, nematodes, flies and humans. Biochemical analysis of the properties of this conserved motif revealed that it could function as a DNA binding domain when expressed in a fusion protein. The in vitro specificity of the Dri DNA binding domain was determined by selection and sequencing of target sites. The Dri consensus site obtained was strikingly similar to that of the Qfo class of homeo domains, although the sequence and predicted secondary structure of the Dri DNA binding domain do not resemble a homeo domain. Analysis of the developmental expression pattern of dri showed a ubiquitous maternal deposit gradually refined to localisation in the mesoderm at germ band extension, then further restriction to a diverse set of tissues including the salivary gland ducts, parts of the gut and a subset of the central nervous system. The phenotype of P - element insertion and deletion mutations of dri were identified as causing embryonic lethality preceded by a disruption of the hindgut and loss of Dri expression in the ring gland. The identification of the novel, conserved DNA - binding domain in Dead ringer offers an explanation for the regulatory activity of several important related proteins and presents an opportunity to use the advantages of the Drosophila model system to clarify the role of these proteins in transcriptional control. / Thesis (Ph.D.)--Departments of Biochemistry and Genetics, 1996.

Rat hepatocytes have previously been reported to possess prostaglandin E₂ receptors of the EP₃-type (EP₃-receptors) that inhibit glucagonstimulated glycogenolysis by decreasing cAMP. Here, the isolation of a functional EP₃ϐ receptor cDNA clone from a rat hepatocyte cDNA library is reported. This clone can be translated into a 362-amino-acid protein, that displays over 95% homology to the EP₃ϐ receptor from mouse mastocytoma. The amino- and carboxy-terminal region of the protein are least conserved. Transiently transfected HEK 293 cells expressed a single binding site for PGE₂ with an apparent Kd of 15 nM. PGE₂ > PGF₂α > PGD₂ competed for [³H]PGE₂ binding sites as did the EP₃ receptor agonists M&B 28767 = sulprostone > misoprostol but not the EP₁ receptor antagonist SC 19220. In stably transfected CHO cells M&B 28767 > sulprostone = PGE₂ > misoprostol > PGF₂α inhibited the forskolin-elicited cAMP formation. Thus, the characteristics of the EP₃ϐ receptor of rat hepatocytes closely resemble those of the EP₃ϐ receptor of mouse mastocytoma.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Greek alphabet delta in title. Includes bibliographical references (leaves 136-155). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--West Virginia University, 2004 / Title from document title page. Document formatted into pages; contains xiii, 119 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri--Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves : 117-131). Also available on the Internet.