The Drosophila GW protein, a posttranscriptional gene regulator that influences progression through mitosis

  • Author / Creator
    Schneider, Mary
  • Regulation of mRNA translation and stability can occur in cytoplasmic compartments known as mRNA processing bodies or P bodies. These compartments contain factors that function in multiple mRNA regulatory pathways and are thought to be centres for coordinating the action of these pathways. One class of proteins that resides in P bodies belongs to the conserved family of GW proteins. Members from this family have been identified only in metazoan genomes and include the prototype human GW182 protein and two additional human paralogues and Caenorhabditis elegans Ain-1 and Ain-2 proteins. In this study, the single Drosophila melanogaster gene encoding a GW protein was characterized. The similarity in structure and function of this gene that were observed in this study, with human orthologues suggest that Drosophila is an appropriate experimentally tractable organism for further advancements in understanding the functions of the human orthologues. This study also contributed evidence supporting the involvement of Drosophila GW in the RNA interference pathway through a physical association with Argonaute 2, an important effector in this pathway. A Drosophila strain carrying a mutation in the gw gene showed multiple mitotic defects in homozygous mutant embryos. The mutant strain was named gawky because of the uncoordinated chromatin movements that were observed in live mutant embryos undergoing mitosis. This observation suggests that Drosophila GW may control the stability and/or translation of mRNAs encoding cell cycle regulators. The endoribonuclease RNase MRP was chosen as a potential mRNA regulator that may be affected in the gw1 mutant strain. In Saccharomyces cerevisiae, RNase MRP degrades the mRNA of the major mitotic cyclin Clb2 and localizes to a P body-like structure. Human RNase MRP also influences the levels of cyclin B mRNA. MRP RNA, the non-coding RNA component of the RNase MRP enzyme has not been previously studied in Drosophila. In this study, expression of Drosophila MRP RNA was verified. MRP RNA was also localized to a subpopulation of structures containing Drosophila GW during mitosis, suggesting that these two components may functionally interact in regulating mitosis.

  • Subjects / Keywords
  • Graduation date
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
    • Department of Cell Biology
  • Supervisor / co-supervisor and their department(s)
    • Dr. A. Simmonds, Cell Biology
  • Examining committee members and their departments
    • Dr. R. Rachubinski, Cell Biology
    • Dr. A. Simmonds, Cell Biology
    • Dr. P. LaPointe, Cell Biology
    • Dr. M. Fritzler, Medicine, University of Calgary
    • Dr. S. Campbell, Biological Sciences