tailieunhanh - Báo cáo khoa học: DNA methylation-mediated nucleosome dynamics and oncogenic Ras signaling

Histone-derived antimicrobial peptides have been identified in various organisms from plants to humans. The rat histone H4 mRNA variants, and rat histogranin (HNr) mRNAs, were recently reported to be involved in the synthesis of H4-(86–100) and its related peptide HNr, respectively. | IFEBS Journal REVIEW ARTICLE DNA methylation-mediated nucleosome dynamics and oncogenic Ras signaling Insights from FAS FAS ligand and RASSF1A Samir K. Patra1 and Moshe Szyf2 1 Cancer Epigenetics Research Kalyani India 2 Department of Pharmacology and Therapeutics McGillUniversity Montreal Canada Keywords apoptosis cancer DNA methylation epigenetics FAS FAS ligand H-Ras K-Ras nucleosome dynamics RASSF1A Correspondence S. K. Patra Cancer Epigenetics Research Kalyani B-7 183 Nadia West Bengal India Fax 91 332 582 8460 Tel 91 943 206 0602 E-mail skpatra_99@ Present address Division of Biochemistry Department of ExperimentalMedicine University of Parma Italy Received 5 June 2008 revised 8 August 2008 accepted 22 August 2008 doi Cytosine methylation at the 5-carbon position is the only known stable base modification found in the mammalian genome. The organization and modification of chromatin is a key factor in programming gene expression patterns. Recent findings suggest that DNA methylation at the junction of transcription initiation and elongation plays a critical role in suppression of transcription. This effect is mechanistically mediated by the state of chromatin modification. DNA methylation attracts binding of methyl-CpG-binding domain proteins that trigger repression of transcription whereas DNA demethylation facilitates transcription activation. Understanding the rules that guide differential gene expression as well as transcription dynamics and transcript abundance has proven to be a taxing problem for molecular biologists and oncologists alike. The use of novel molecular modeling methods is providing exciting insights into the challenging problem of how methylation mediates chromatin dynamics. New data implicate lipid rafts as the coordinators of signals emanating from the cell membrane and are converging on the mechanisms linking DNA methylation and chromatin dynamics. This review focuses on some of these recent .