Doctor of Philosophy (PhD)
First Advisor's Name
Charles H. Bigger
First Advisor's Committee Title
Second Advisor's Name
Martin L. Tracey, Jr.
Third Advisor's Name
Sylvia L, Smith
Fourth Advisor's Name
Fifth Advisor's Name
Sixth Advisor's Name
Date of Defense
One goal of comparative immunology is to derive inferences about evolutionary pathways in the development of immune-defense systems. Almost 700 million years ago, a major divergence occurred in the phylogeny of animals, spitting all descendants into either the protostome or deuterostome (includes vertebrates) lineages. Genes have evolved independently along these lineages for that amount of time. Cnidarians originated before that divergence event, and can hold clues as to which immune response genes are homologous to both lineages. This work uses the gorgonian coral, Swiftia exserfa, for two major reasons: 1) because of their phylogenetic position, corals are an important animal model in studies concerning the phylogeny of immune-response genes, and 2) nothing is known about the genes controlling immunocompetence in corals. The work described here has important implications in both innate and adaptive immunity.
The vertebrate complement system is a major component of innate immunity. C3 is a critical component of the three pathways of complement. Because of its opsonic properties, a C3-like protein is expected to have evolved early. However, currently available data suggests that complement-like components are unique to the deuterostome lineage. This work describes the cloning and characterization of a C3- like gene from S. exserta. The deduced polypeptide sequence reveals conservation of multiple, functionally critical, sites while sharing physiochemical and structural properties with the complement components C3/C4/C5.
Antigen processing, via intracellular enzymatic proteasomes, is a major requirement of vertebrate adaptive immunity. These organelles have a catalytic core, through which pass intracellular proteins for degradation into peptides presentable to the immune system. LMP 7 is one component of the paralogous “immunoproteasome”. LMP 7 is a paralog of the ubiquitous LMP X, but is restricted to vertebrates. While LMP 7 is absent in the coral, this work describes a coral LMP X gene. Phylogenetic analyses, along with hydropathy profiling of a critical portion of the invertebrate and vertebrate paralogous genes, suggests that some invertebrates have two diverging LMP X genes. In some cases, one LMP X protein shares characteristics with vertebrate LMP 7. This work presents new evidence for how the LMP X and 7 genes evolved.
Dishaw, Larry J., "Immunophylogenetic aspects of a Gorgonian coral" (2002). FIU Electronic Theses and Dissertations. 2825.
In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/
This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).