The discovery of oncogenes revolutionized analysis of the molecular bases of cancer. Oncogenes provided starting points for molecular dissection of the signaling pathways that govern normal cell growth and for elucidation of the events that lead to oncogenesis. The fos oncogene is responsible for induction of osteosarcomas and cell transformation by the Finkel-Biskis-Jinkins murine sarcoma virus. Its protein product, Fos, functions as a component of the inducible mammalian transcription factor AP 1. Induction of c-fos expression is associated with mitogenesis, differentiation, apoptosis and excitation of neurons. It is believed to participate in complex signal transduction networks that couple extracellular stimuli to long-term cellular responses by regulating gene expression. Transformation by fos is thought to be a consequence of inappropriate regulation of gene expression. Three major specific aims are addressed in this application. The first concerns the identification and characterization of fos target genes responsible for cell transformation by Representational Difference Analysis and cDNA array hybridization approaches. In the second specific aim we will follow up preliminary studies demonstrating that DNA 5-methylcytosine transferase-1 (dnmt1) is a fos target gene involved in cell transformation. We plan to identify genes that are methylated by dnmt1 in fos transformed cells and analyze their contribution to transformation. The third specific aim concerns the role of reduction/oxidation (redox) in the regulation of Fos function and cell growth. Previously, we demonstrated that the bifunctional redox/endonuclease gene, ref-1, regulates the DNA binding activity of Fos through a conserved cysteine residue in the DNA binding domain. Disruption of the Ref-1 gene in mice causes early embryonic lethality. We will introduce point mutations into Ref-1, by homologous recombination in embryonic stem cells that ablate the redox and nuclease functions of Ref-1 independently. These cells will be used to generate mutant mice and cell lines that will be used to analyze the role of Ref-1 in modulating AP1 activity and cell growth.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA084139-02
Application #
6342208
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Freeman, Colette S
Project Start
2000-01-01
Project End
2004-12-31
Budget Start
2001-01-01
Budget End
2001-12-31
Support Year
2
Fiscal Year
2001
Total Cost
$392,805
Indirect Cost
Name
St. Jude Children's Research Hospital
Department
Type
DUNS #
067717892
City
Memphis
State
TN
Country
United States
Zip Code
38105
Ordway, Jared M; Fenster, Steven D; Ruan, Hong et al. (2005) A transcriptome map of cellular transformation by the fos oncogene. Mol Cancer 4:19
Ordway, Jared M; Williams, Katy; Curran, Tom (2004) Transcription repression in oncogenic transformation: common targets of epigenetic repression in cells transformed by Fos, Ras or Dnmt1. Oncogene 23:3737-48
Li, Leyi; Connelly, Michele C; Wetmore, Cynthia et al. (2003) Mouse embryos cloned from brain tumors. Cancer Res 63:2733-6
Ordway, Jared M; Eberhart, Derek; Curran, Tom (2003) Cysteine 64 of Ref-1 is not essential for redox regulation of AP-1 DNA binding. Mol Cell Biol 23:4257-66
Ordway, Jared M; Curran, Tom (2002) Methylation matters: modeling a manageable genome. Cell Growth Differ 13:149-62
Ng, L; Pedraza, P E; Faris, J S et al. (2001) Audiogenic seizure susceptibility in thyroid hormone receptor beta-deficient mice. Neuroreport 12:2359-62