• myGriffith
    • Staff portal
    • Contact Us⌄
      • Future student enquiries 1800 677 728
      • Current student enquiries 1800 154 055
      • International enquiries +61 7 3735 6425
      • General enquiries 07 3735 7111
      • Online enquiries
      • Staff phonebook
    View Item 
    •   Home
    • Griffith Theses
    • Theses - Higher Degree by Research
    • View Item
    • Home
    • Griffith Theses
    • Theses - Higher Degree by Research
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

  • All of Griffith Research Online
    • Communities & Collections
    • Authors
    • By Issue Date
    • Titles
  • This Collection
    • Authors
    • By Issue Date
    • Titles
  • Statistics

  • Most Popular Items
  • Statistics by Country
  • Most Popular Authors
  • Support

  • Contact us
  • FAQs
  • Admin login

  • Login
  • The Thioredoxin System: Gene Structure and Expression Studies in Response to Oxidative Stress

    Thumbnail
    View/Open
    02Whole.pdf (2.193Mb)
    Author(s)
    Osborne, Simone A.
    Primary Supervisor
    Tonissen, Kathryn
    Other Supervisors
    Clarke, Frank
    Year published
    2005
    Metadata
    Show full item record
    Abstract
    The thioredoxin system is comprised of thioredoxin and thioredoxin reductase and is widely distributed in prokaryotes and eukaryotes. The thioredoxin system plays an important role in maintaining the redox state of the cell and in protecting the cell against oxidative stress by scavenging reactive oxygen species through a variety of mechanisms. However, elevated levels of the thioredoxin system are also present in many forms of cancer and with persistent oxidative stress associated with many types of cancer, an understanding of how the expression of the thioredoxin system is controlled under basal conditions and in response ...
    View more >
    The thioredoxin system is comprised of thioredoxin and thioredoxin reductase and is widely distributed in prokaryotes and eukaryotes. The thioredoxin system plays an important role in maintaining the redox state of the cell and in protecting the cell against oxidative stress by scavenging reactive oxygen species through a variety of mechanisms. However, elevated levels of the thioredoxin system are also present in many forms of cancer and with persistent oxidative stress associated with many types of cancer, an understanding of how the expression of the thioredoxin system is controlled under basal conditions and in response to oxidative stress, may aid in elucidating the link between the thioredoxin system and cancer. Initial studies were focused on determining the structure of the thioredoxin reductase gene. A mouse genomic library was screened and a 15kb clone containing 11 exons was mapped and the important regions sequenced. The remaining exons were identified by data base analysis. The structure of the human thioredoxin reductase gene was mapped by data base searches and identified many 5' splice variants involved in an extremely complex regulation of gene expression. The human thioredoxin promoter region directs expression of the thioredoxin gene under both housekeeping conditions and during stimulation by oxidative stress reagents. Two potential transcription start regions had previously been described. In this project luciferase assays and Real-Time PCR analysis were used to characterise the core human thioredoxin promoter region containing these alternate transcription start sites and to analyse the action of other regulatory elements present within the human thioredoxin promoter region in basal expression and in response to oxidative stress. These studies revealed an overlapping promoter region that appears to utilise non-TATA and TATA box containing promoters in conjunction with Sp1 binding sites, oxidative and antioxidant response elements to elicit maximal gene induction to oxidative stress stimuli (tert-butylhydroquinone). Other studies involving human skin cancer cell lines enabled the levels of the thioredoxin system to be measured and correlated with cell pigmentation to ultimately investigate the effect of the thioredoxin system on melanogenesis, a cellular process influenced by levels of oxidative stress. These studies suggested that due to its reactive oxygen species scavenging activities, the thioredoxin system can affect melanogenesis by altering the production of pigment without affecting tyrosinase activity.
    View less >
    Thesis Type
    Thesis (PhD Doctorate)
    Degree Program
    Doctor of Philosophy (PhD)
    School
    School of Biomolecular and Biomedical Sciences
    DOI
    https://doi.org/10.25904/1912/3264
    Copyright Statement
    The author owns the copyright in this thesis, unless stated otherwise.
    Subject
    Thioredoxin
    Gene expression
    Oxidative stress
    Cancer
    Publication URI
    http://hdl.handle.net/10072/367950
    Collection
    • Theses - Higher Degree by Research

    Footer

    Disclaimer

    • Privacy policy
    • Copyright matters
    • CRICOS Provider - 00233E

    Tagline

    • Gold Coast
    • Logan
    • Brisbane - Queensland, Australia
    First Peoples of Australia
    • Aboriginal
    • Torres Strait Islander