Changes in miRNA Expression in a Model of Microcephaly

miRNAs function to regulate gene expression through post-transcriptional mechanisms to potentially regulate multiple aspects of physiology and development. Whole transcriptome analysis has been conducted on the citron kinase mutant rat, a mutant that shows decreases in brain growth and development. The resulting differences in RNA between mutant and wild-type controls can be used to identify genetic pathways that may be regulated differentially in normal compared to abnormal neurogenesis. The goal of this thesis was to verify, with quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), changes in miRNA expression in Cit-k mutants and wild types. In addition to confirming miRNA expression changes, bio-informatics software TargetScan 5.1 was used to identify potential mRNA targets of the differentially expressed miRNAs. The miRNAs that were confirmed to change include: rno-miR-466c, mmu-miR-493, mmu-miR-297a, hsa-miR-765, and hsa-miR-1270. The TargetScan analysis revealed 347 potential targets which have known roles in development. A subset of these potential targets include genes involved in the Wnt signaling pathway which is known to be an important regulator of stem cell development.

Investigating the Affects of Cucurbitacin-I on Cellular Motility

Cellular migration is an integral component of many biological processes including immune function, wound healing and cancer cell metastasis. A complete model illustrating the mechanism by which cells accomplish movement is still lacking. Exploring the affects of various drugs on cell motility may be instrumental in discovering new proteins which mediate cell movement. This project aims ultimately to characterize the molecular target of the drug Cucurbitacin-I, a natural plant product. This drug has been shown to inhibit migration of epithelial sheets and may have anti-tumor activity. In this paper, we show that Cucurbitacin-I inhibits the migration of MDCK and B16F1 cells. The drug also affects the integrity of the actin cytoskeleton of these cells by indirectly stabilizing filamentous actin. Cucurbitacin-I does not, however, have an effect on the motility or cytoskeletal morphology of the soil amoeba, Dictyostelium discoidium.