Thesis
Dynamics of the aaap locus in Anaplasma marginale
Washington State University
Master of Science (MS), Washington State University
2010
Handle:
https://hdl.handle.net/2376/101148
Abstract
Anaplasmosis, the most prevalent tick-transmitted disease of cattle, is caused by the rickettsial intracellular parasite Anaplasma marginale. The pathogen replicates within a parasitophorous vacuole formed from the invagination of the erythrocyte membrane. Several strains of A. marginale form "tails" or "appendages" which are attached to, and extend out from, the cytoplasmic side of the parasitophorous vacuole. Genomic analysis of the parasite antigen distributed along the appendage led to the discovery of the aaap gene family located within a highly plastic region in the genome. To investigate locus plasticity, several loci were cloned, sequenced and aligned to identify sites of insertions and deletions. Our findings show that repeat sequences both within and between genes facilitate rearrangement events within the locus. Structural variation of the locus in the St. Maries strain was further investigated during infection of different cellular environments, i.e. bovine erythrocytes and tick cells, with a reduction in subpopulations of the aaap locus within the tick as compared to erythrocytes. Interestingly, subpopulations bearing alternative locus structures began to arise again when the pathogen was transferred from the tick environment into a naìˆve calf. Additionally, the Aaap protein expression profile between blood and tick samples showed a regulatory shift, indicating a hostspecific response. The role the aaap locus may play in the pathogenesis of the bovine host or in tick infection/transmission remains unknown; however the changes in aaap locus subpopulations, locus structure, and protein expression indicate that these genes have a role in strain diversification.
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Details
- Title
- Dynamics of the aaap locus in Anaplasma marginale
- Creators
- Heather Marie Fallquist
- Contributors
- Kelly Brayton (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Molecular Biosciences, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525087601842
- Language
- English
- Resource Type
- Thesis