Virginia Tech
    • Log in
    View Item 
    •   VTechWorks Home
    • ETDs: Virginia Tech Electronic Theses and Dissertations
    • Doctoral Dissertations
    • View Item
    •   VTechWorks Home
    • ETDs: Virginia Tech Electronic Theses and Dissertations
    • Doctoral Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Farnesyltransferase: Gene Expression in Plants and Role in Plant Development

    Thumbnail
    View/Open
    DZhou.pdf (722.6Kb)
    Downloads: 149
    Date
    1997-03-14
    Author
    Zhou, Dafeng
    Metadata
    Show full item record
    Abstract
    Protein farnesyltransferase (FTase, E. C. 2.5.1.21) post-translationally modifies regulatory proteins involved in controlling cell growth, division, and differentiation. Recently, a cDNA clone (PsFTb) encoding a pea (Pisum sativum) FTase b subunit was isolated. Initial studies led to the hypothesis that FTase plays a role in the regulation of plant cell division. To gain insight into FTase function in plants, a detailed study of the expression pattern of FTase genes was carried out. A cDNA (NgFTb) encoding the b subunit of tobacco FTase was cloned from a Nicotiana glutinosa cDNA library to initiate studies in tobacco. In tobacco BY-2 suspension culture, levels of NgFTb mRNA and FTase activity transiently increased at the early log phase of cell growth and rapidly declined before cells entered stationary phase. These data, along with inhibitor studies in the BY-2 system, support our hypothesis. To understand the expression and regulation of pea FTase subunit genes, 5'-upstream sequences of both pea FTase subunit genes (PsFTb and PsFTa) were cloned from a pea genomic library. The 5'-upstream sequence (~2 kb) of PsFTa was fused to GUS (b-glucuronidase) and GFP (green fluorescent protein) reporter genes and introduced into tobacco plants. This 2 kb upstream region appears insufficient to provide PsFTa promoter function. On the other hand, 3.2 kb of PsFTb 5'-upstream sequence expressed as a PsFTb:GUS construct is fully functional in transgenic tobacco plants. GUS expression was most prominent in actively growing cells supporting FTase involvement in plant cell cycle control. GUS activity was also found in mature and imbibed embryos but not premature embryos, consistent with the role of FTase in abscisic acid (ABA) signaling. An unexpected pattern of GUS activity, not correlated with dividing cells or ABA signaling, was also observed in the transgenic plants. GUS activity was detected in vascular bundles adjacent to actively-growing tissues and in regions that connect two organs, e.g., junctions between stems and leaf petioles, cotyledons and hypocotyls, roots and hypocotyls. Auxin promotes PsFTb expression while light and sucrose inhibit expression. These spatial and temporal expression patterns strongly suggest that FTase has a broader role associated with regulation of nutrient transportation or allocation in plants.
    URI
    http://hdl.handle.net/10919/30483
    Collections
    • Doctoral Dissertations [15920]

    If you believe that any material in VTechWorks should be removed, please see our policy and procedure for Requesting that Material be Amended or Removed. All takedown requests will be promptly acknowledged and investigated.

    Virginia Tech | University Libraries | Contact Us
     

     

    VTechWorks

    AboutPoliciesHelp

    Browse

    All of VTechWorksCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    Log inRegister

    Statistics

    View Usage Statistics

    If you believe that any material in VTechWorks should be removed, please see our policy and procedure for Requesting that Material be Amended or Removed. All takedown requests will be promptly acknowledged and investigated.

    Virginia Tech | University Libraries | Contact Us