Farnesyltransferase: Gene Expression in Plants and Role in Plant Development

dc.contributor.authorZhou, Dafengen
dc.contributor.committeechairCramer, Carole L.en
dc.contributor.committeecochairYang, Zhenbiaoen
dc.contributor.committeememberGrabau, Elizabeth A.en
dc.contributor.committeememberLacy, George H.en
dc.contributor.committeememberWinkel, Brenda S. J.en
dc.contributor.departmentPlant Pathology, Physiology, and Weed Scienceen
dc.date.accessioned2014-03-14T20:21:50Zen
dc.date.adate1997-03-14en
dc.date.available2014-03-14T20:21:50Zen
dc.date.issued1997-03-14en
dc.date.rdate1998-03-15en
dc.date.sdate1998-07-25en
dc.description.abstractProtein 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.en
dc.description.degreePh. D.en
dc.identifier.otheretd-351514312971890en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-351514312971890/en
dc.identifier.urihttp://hdl.handle.net/10919/30483en
dc.publisherVirginia Techen
dc.relation.haspartDZhou.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectFarnesyltransfeen
dc.subjectExpressionen
dc.subjectGUSen
dc.subjectPrenylationen
dc.subjectGFPen
dc.subjectIsoprenoiden
dc.titleFarnesyltransferase: Gene Expression in Plants and Role in Plant Developmenten
dc.typeDissertationen
thesis.degree.disciplinePlant Pathology, Physiology, and Weed Scienceen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en
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