How is chromatin activity regulated?

In order to properly regulate gene transcription, the cell uses different multisubunit protein complexes to modulate chromatin activity. These processes include ATP-dependent nucleosome remodeling, DNA modification, histone modification, recognition of specific histone modifications, and DNA and RNA binding. During nucleosome remodeling, chromatin complexes use the energy from ATP hydrolysis to alter the position and structure of nucleosomes. They may eject, slide, or reposition nucleosomes to either hide or expose specific DNA regions. During histone modification, histone proteins undergo several post-translational modifications like methylation, phosphorylation, and acetylation, where each may have the ability to influence gene expression. Histone modifications regulate the physical properties of chromatin and its associated transcriptional state. This can be done directly, where acetyl groups repel negatively charged DNA to form open chromatin conformation; or it can be done through protein adaptors such as effectors.