Relationships between chromatin organization and DNA methylation in determining gene expression

Chromatin ir the natural substrate for the control of gene expression. Chromatin contains DNA, the transcriptional machinery and structural proteins such as histones. Recent advances demonstrate that transcriotional activity of a gene Is Inr largely controlled by the packaging of the template within chromatin. The covalent modification of chromatin provides an attractive mechanism for establishing and maintaining stable states of gene activity. DNA methylation and histone acetylation alter the nucleosomal infrastructure to repress or activate transcription. These covalent modifications have causal roles in both promoter-specific events and the global control of chromosomal activity. DNA methylation and histone acetylation have a major impact in both oncogenic transformation and normal development.