University of SaskatchewanHARVEST
  • Login
  • Submit Your Work
  • About
    • About HARVEST
    • Guidelines
    • Browse
      • All of HARVEST
      • Communities & Collections
      • By Issue Date
      • Authors
      • Titles
      • Subjects
      • This Collection
      • By Issue Date
      • Authors
      • Titles
      • Subjects
    • My Account
      • Login
      JavaScript is disabled for your browser. Some features of this site may not work without it.
      View Item 
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item

      Characterization of the two genes encoding cytoplasmic ribosomal protein L23a in Arabidopsis thaliana

      Thumbnail
      View/Open
      PHDTHESIS-FINALCOMPILED.pdf (18.34Mb)
      Date
      2005-11-09
      Author
      McIntosh, Kerri Bryn
      Type
      Thesis
      Degree Level
      Doctoral
      Metadata
      Show full item record
      Abstract
      RPL23a is one of the ~80 ribosomal proteins (r-proteins) of the cytoplasmic ribosome in the model plant Arabidopsis thaliana. The objectives of this research were to establish Arabidopsis RPL23a as a functional r-protein, characterize expression patterns for the two genes (RPL23aA and B) encoding RPL23a using reverse transcription PCR (RT-PCR), and identify regulatory elements controlling the expression of RPL23aA and B. Complementation of a yeast l25 mutant with AtRPL23aA demonstrated that AtRPL23aA can fulfill all the essential functions of L25 in vivo. A survey of various Arabidopsis tissue types showed that, while RPL23aA and B expression patterns both showed increased transcript abundance in mitotically active tissues, RPL23aB transcript levels were generally lower than those of RPL23aA and responded differently to abiotic stresses. In order to determine cis regulatory elements controlling RPL23aA and B expression, the 5’ regulatory region (RR) of each gene was characterized via plants carrying a series of 5’ RR deletion fragments upstream of a reporter. Transcript start sites and 5’ untranslated regions (UTRs) for both RPL23aA and B were also characterized using primer extension, and transcripts from 5’ deletion transgenics were amplified using RT-PCR. No correlation was observed between putative cis-acting elements and the expression patterns from the RPL23aA and B deletion transgenics, although a 102 bp sequence in the RPL23aB 5’ RR was found to contain pollen-specific elements. 5’ leader introns were found in each RPL23a gene, and amplification of transgene transcripts from deletion series plants indicated the importance of post-transcriptional and translational regulation in RPL23aA and B expression. This thesis work is the first demonstration of a plant RPL23a protein as a functional member of the L23/L25 (L23p) conserved r-protein family, and is one of the few in-depth studies of the regulation of r-protein genes in plants. While the majority of previous research on plant r-protein gene expression has focused solely on transcript levels, I show herein that post-transcriptional mechanisms have a critical role in regulating these genes, and thus plant r-protein genes more strongly resemble their mammalian counterparts than those of yeast in terms of structure and regulation.
      Degree
      Doctor of Philosophy (Ph.D.)
      Department
      Biology
      Program
      Biology
      Supervisor
      Bonham-Smith, Peta C.
      Committee
      Roesler, William J.; Messier, François; Kaminskyj, Susan G. W.; Davis, Arthur R.; Bailey-Serres, Julia
      Copyright Date
      November 2005
      URI
      http://hdl.handle.net/10388/etd-11222005-135848
      Subject
      regulatory region
      yeast complemetation
      ribosome
      ribosomal protein
      Arabidopsis
      gene expression
      Collections
      • Graduate Theses and Dissertations
      University of Saskatchewan

      University Library

      The University of Saskatchewan's main campus is situated on Treaty 6 Territory and the Homeland of the Métis.

      © University of Saskatchewan
      Contact Us | Disclaimer | Privacy