HOW DOES DNA METHYLATION REPRESS TRANSCRIPTION

DNA methylation has an essential regulatory function in mammalian deve lopment, serving to repress nontranscribed genes stably in differentia ted adult somatic cells. Recent data implicate transcriptional repress ors specific for methylated DNA and chromatin assembly in this global control of gene activity. The assembly of specialized nucleosomal stru ctures on methylated DNA helps to explain the capacity of methylated D NA segments to silence transcription more effectively than conventiona l chromatin, Specialized nucleosomes also provide a potential molecula r mechanism for the stable propagation of DNA methylation-dependent tr anscriptional silencing through cell division.