One important mechanism of transcriptional control is genomic imprinting, a process by which a gene is expressed from only one parental allele. Loss of imprinting is implicated in human disease and cancer. Alterations in regulation of the imprinted genes IGF2 and HI9 have been shown to contribute to Beckwith-Wiedemann Syndrome, a syndrome of overgrowth and tumor development. These genes are expressed from different parental alleles, but their imprinted expression is regulated by common DNA elements. An important molecular difference between alleles is differential methylation of CpGs in the H19 5' region. This differentially methylated domain (DMD) is required for imprinted expression of both HI9 and Igf2 and methylation of the DMD is correlated with the silencing of HI9. How this DNA methylation is interpreted and translated into a repressed state is unknown. A family of proteins, the Methyl-CpG binding proteins (Mbd), has been identified that may be the link between methylation and silencing. I propose to test the hypothesis that Mbd proteins are required for the silencing of imprinted genes. I will employ an RNAi approach to reduce Mbd activity in early embryos, and then determine the effect reduction of Mbd activity has on imprinted gene expression and methylation. I will also identify which Mbds are bound to repressive methylated chromatin at imprinted loci in embryonic cell lines.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32GM069103-01
Application #
6691103
Study Section
Special Emphasis Panel (ZRG1-F08 (20))
Program Officer
Wolfe, Paul B
Project Start
2004-01-01
Project End
2005-12-31
Budget Start
2004-01-01
Budget End
2004-12-31
Support Year
1
Fiscal Year
2003
Total Cost
$41,608
Indirect Cost
Name
University of Pennsylvania
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Reese, Kimberly J; Lin, Shu; Verona, Raluca I et al. (2007) Maintenance of paternal methylation and repression of the imprinted H19 gene requires MBD3. PLoS Genet 3:e137
Reese, K J; Bartolomei, M S (2006) Establishment and maintenance of H19 imprinting in the germline and preimplantation embryo. Cytogenet Genome Res 113:153-8