Scott Baird (Committee Member), Athanasios Bubulya (Committee Member), Mill Miller (Committee Member), Labib Rouhana (Advisor)
Master of Science (MS)
Tubulin comprises the structural element of microtubules and Tau is one of many microtubule-associated proteins. Tau Tubulin Kinase (TTBK) phosphorylates both Tau and Tubulin and is required for the initial steps of cilia formation. Due to the structural similarities between cilia and sperm flagella, as well as the enriched expression of TTBK1 and TTBK2 in human testes, we hypothesized that TTBK homologs play a role in sperm maturation. This hypothesis was tested in the planarian Schmidtea mediterranea, a lophotrochozoan model capable of whole-body regeneration and development a complete reproductive system post-embryonically. Six TTBK homologs were identified in the genome of S. mediterranea. Analysis by whole-mount in situ hybridization revealed that all six homologs (Smed-TTBK-a, -b, -c, -d, -e, and -f) are preferentially expressed in the testes of sexual planarians. Functional analyses by RNA-interference (RNAi) revealed that Smed-TTBK-d is specifically required for sperm development. Smed-TTBK-d RNAi also results in behavioral defects which appear to be caused at least in part by structural abnormalities in ciliated epidermal cells that power planarian gliding. Altogether, these results demonstrate that TTBK function is essential for development of ciliated structures in planarians.
Department or Program
Department of Biological Sciences
Year Degree Awarded
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