Customizing Host Chromatin: A Bacterial Tale
Résumé
Chromatin is located within the nuclei of eukaryotic cells and is composed of DNA wrapped around histone proteins. The highly ordered compaction of chromatin is crucial for the different functions encoded by the genetic material. These range from maintaining cell identity and genome integrity to adapting to environmental stimuli and cell replication. At the center of the chromatin language is its structural organization. This depends on the position and reversible covalent modifications to histone proteins and their cross talk with DNA and regulatory proteins. The basic unit of chromatin is the nucleosome, which is composed of an octamer of four histone proteins (H2A, H2B, H3, and H4) around which ∼147 bases of DNA are wrapped, with the linker histone (H1) outside the core structure providing structural integrity to the complex. Nucleosome remodelers are ATP-dependent enzymes that modify the chromatin structure through translocation, eviction, and introduction of histone variants ( 1 , 2 ), while histone-modifying enzymes introduce reversible covalent posttranslational modifications (PTMs) to histone tails.