File:Luong LD SA F2.jpg

Summary
Figure is adapted from Luong, P. Basic Principles of Genetics, Connexions Web site (2009) under a Creative Commons Attribution License (CC-BY 3.0). Further modification of the figure is performed by the image uploader with reference from Davis PK, Brackmann RK. Chromatin remodeling and cancer. Cancer Biol Ther. 2:22 (2003)..

Caption: Chromatin remodeling complexes in the dynamic regulation of transcription: In the presence of acetylated histones (HAT mediated) and absence of methylase (HMT) activity, chromatin is loosely packaged. Additional nucleosome repositioning by chromatin remodeler complex, SWI/SNF opens up DNA region where transcription machineray proteins, like RNA Pol II, transcription factors and co-activators bind to turn on gene transcription. In the absence of SWI/SNF, nucleosomes can not move farther and remain tightly aligned to one another. Additional methylation by HMT and deacetylation by HDAC proteins condenses DNA around histones and thus, make DNA unavailable for binding by RNA Pol II and other activators, leading to gene silencing.