mRNA localization is a powerful post-transcriptional mechanism of gene expression that allows for protein expression in distinct cellular locations. This process is exploited in a number of organisms and cell types, and has been particularly well studied in developmental contexts. One such model system is that of the Vg1 mRNA which is localized to the vegetal cortex of the Xenopus laevis oocyte. The primary focus of this dissertation is an investigation into how the Vg1 mRNA is translationally silenced during localization. The results of this investigation are presented in Chapter 2, and implicate the miRNA pathway, specifically Argonaute proteins and the let-7 family of miRNAs, in translational repression. In addition, known Xenopus RNA-binding proteins were investigated as potential translational repressors, and the results of these experiments are presented in the Appendix. In the process of this investigation an in vitro translation extract from Xenopus oocytes was developed, which is documented in Chapter 3. A secondary aim was to understand how Vg1 is localized along the microtubule cytoskeleton. Chapter 4 shows that the orientation of the microtubule cytoskeleton at the vegetal pole of the oocyte and the activity of kinesin motor proteins are critical for the transport of this mRNA. Together, these data represent novel insights into mRNA transport and translational control.
Pratt, Catherine A.,
"Translational control and active transport of Vg1 mRNA in Xenopus laevis oocytes"
Molecular Biology, Cell Biology, and Biochemistry Theses and Dissertations.
Brown Digital Repository. Brown University Library.