page_title: Chromatin remodeling
section_title: Significance
hierarchical_section_title: Chromatin remodeling / Significance
context_page_description: Chromatin remodeling is the dynamic modification of chromatin architecture to allow access of condensed genomic DNA to the regulatory transcription machinery proteins, and thereby control gene expression. Such remodeling is principally carried out by 1 covalent histone modifications by specific enzymes, e.g., histone acetyltransferases, deacetylases, methyltransferases, and kinases, and 2 ATP-dependent chromatin remodeling complexes which either move, eject or restructure nucleosomes. Besides actively regulating gene expression, dynamic remodeling of chromatin imparts an epigenetic regulatory role in several key biological processes, egg cells DNA replication and repair; apoptosis; chromosome segregation as well as development and pluripotency. Aberrations in chromatin remodeling proteins are found to be associated with human diseases, including cancer. Targeting chromatin remodeling pathways is currently evolving as a major therapeutic strategy in the treatment of several cancers.
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 machinery 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.
exif: {}