The epigenetic modification of cytosine in DNA is essential for normal vertebrate development yet adds a substantial mutagenic burden on the organism. This project seeks to understand the mechanisms of mutation at CpG sites and to determine how methylation patterns change during transformation and contribute to gene inactivation. Sequencing of mutations in tumor suppressor genes such as p53 in human cancers has shown that CpG methylation sites are common sites for mutations in somatic cells, as well as in the human germline. DNA methylation therefore contributes very significantly to the generation of human point mutations and these mutations are responsible, in some cases, for the activation of tumor suppressor genes. We will investigate methylation changes in human bladder cancer since our preliminary studies have already identified some of the key genetic changes involved in the multistep transformation of human uroeptithelium. New genetic changes involved in the multistep transformation of human uroepithelium. New genetic assays we have established, will be used to fully define the role of DNA methylation in generating CT transition mutations. In particular, we will follow-up our observation that the DNA methyltransferase itself is capable of inducing a high percentage of transitions. Since we are interested in understanding the role of methylation in controlling the expression of vertebrate genes, we will also use a model system we have derived to investigate the molecular mechanisms of genomic imprinting. A somatic cell line has been established which contains a maternal duplication/paternal deficiency of Igf2 which can be induced to express Igf2 by 5-azacytidine or BudR treatment. Our goals are therefore to determine how methylation patterns are established, their roles in suppressing the activities of certain genes during differentiation and transformation and to determine the significance of this process in the generation of human mutations.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Unknown (R35)
Project #
5R35CA049758-11
Application #
2882362
Study Section
Special Emphasis Panel (SRC (88))
Program Officer
Okano, Paul
Project Start
1989-05-01
Project End
2001-02-28
Budget Start
1999-03-11
Budget End
2000-02-29
Support Year
11
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Southern California
Department
Biochemistry
Type
Schools of Medicine
DUNS #
041544081
City
Los Angeles
State
CA
Country
United States
Zip Code
90089
Kelly, Theresa K; Miranda, Tina Branscombe; Liang, Gangning et al. (2010) H2A.Z maintenance during mitosis reveals nucleosome shifting on mitotically silenced genes. Mol Cell 39:901-11
Kelly, Theresa K; De Carvalho, Daniel D; Jones, Peter A (2010) Epigenetic modifications as therapeutic targets. Nat Biotechnol 28:1069-78
Gonzalgo, Mark L; Jones, Peter A (2002) Quantitative methylation analysis using methylation-sensitive single-nucleotide primer extension (Ms-SNuPE). Methods 27:128-33
Nguyen, C; Liang, G; Nguyen, T T et al. (2001) Susceptibility of nonpromoter CpG islands to de novo methylation in normal and neoplastic cells. J Natl Cancer Inst 93:1465-72
Pao, M M; Tsutsumi, M; Liang, G et al. (2001) The endothelin receptor B (EDNRB) promoter displays heterogeneous, site specific methylation patterns in normal and tumor cells. Hum Mol Genet 10:903-10
Nguyen, C T; Gonzales, F A; Jones, P A (2001) Altered chromatin structure associated with methylation-induced gene silencing in cancer cells: correlation of accessibility, methylation, MeCP2 binding and acetylation. Nucleic Acids Res 29:4598-606
Pao, M M; Liang, G; Tsai, Y C et al. (2000) DNA methylator and mismatch repair phenotypes are not mutually exclusive in colorectal cancer cell lines. Oncogene 19:943-52
Robertson, K D; Jones, P A (2000) DNA methylation: past, present and future directions. Carcinogenesis 21:461-7
Jones, P A (1999) The DNA methylation paradox. Trends Genet 15:34-7
Robertson, K D; Uzvolgyi, E; Liang, G et al. (1999) The human DNA methyltransferases (DNMTs) 1, 3a and 3b: coordinate mRNA expression in normal tissues and overexpression in tumors. Nucleic Acids Res 27:2291-8

Showing the most recent 10 out of 71 publications