Insights into Directional Motor-Driven RNA Localization from the Xenopus Oocyte Gagnon, James A creator 2011 x, 222 p. born digital Thesis (Ph.D. -- Brown University (2011) Mowry, Kimberly Director Johnson, Mark Reader McKeown, Mike Reader Dahlberg, Albert Reader Singer, Robert Reader Brown University. BIOMED: Molecular Biology, Cell Biology, and Biochemistry sponsor theses RNA localization is a widely conserved mechanism for generating cellular asymmetry. In Xenopus oocytes, microtubule-dependent transport of RNAs to the vegetal cortex underlies germ layer patterning. However, the mechanisms that control transport and directionality during asymmetric RNA transport are not yet clear. We have analyzed the participation of kinesin and dynein motors in vegetal RNA transport and identified a direct role for kinesin-1 and cytoplasmic dynein. Moreover, in vivo interference and biochemical experiments reveal a key function for multiple motors, specifically kinesin-1, kinesin-2 and cytoplasmic dynein, and suggest that these motors may interact during transport. Critically, we have discovered a sub-population of microtubules with plus ends at the vegetal cortex, supporting roles for these kinesin motors in vegetal RNA transport. Using a novel approach to measure directionality of mRNA transport in live oocytes, we observe discrete domains of unidirectional and bidirectional transport that are dependent on distinct molecular motors. Specifically, both dynein and kinesin motors mediate steps in the vegetal RNA transport pathway, with dynein acting prior to kinesin. Moreover, dynein, but not kinesin-1, promotes unidirectional transport of RNA towards the vegetal cortex. Thus, vegetal RNA transport occurs through a multi-step pathway, providing a new framework for understanding the mechanistic basis of cell polarity. Molecular Motors RNA Localization Developmental biology RPB 20111003 engEnglish10.7301/Z0B27SJ6In CopyrightCollection is open for research.dissertations