Esa1mediated

Esa1mediated refers to the activities governed by Esa1, a histone acetyltransferase in the yeast Saccharomyces cerevisiae. Esa1 is the catalytic subunit of the NuA4 histone acetyltransferase complex, a multi-subunit assembly that modulates chromatin structure and function.

The primary biochemical activity of Esa1 within NuA4 is the acetylation of histones, notably histones H4 and H2A. By adding acetyl groups to these histones, Esa1 promotes a more open and accessible chromatin state, which in turn facilitates transcriptional initiation and elongation, as well as the deposition and exchange of histone variants. This acetylation also serves as a signal to recruit chromatin readers and remodelers that influence gene expression patterns.

Esa1-mediated chromatin modifications play a significant role in the DNA damage response and repair. In the presence of DNA lesions, NuA4-dependent acetylation helps relax chromatin around break sites, enhancing access for repair factors and contributing to efficient genome maintenance. It is also involved in telomere maintenance and normal cell cycle progression, reflecting broader roles in genome stability.

regulation and conservation: Esa1 activity is dependent on the integrity of the NuA4 complex, and loss or impairment of Esa1 leads to defects in histone acetylation, transcriptional misregulation, and reduced viability in yeast. Across eukaryotes, functional homologs of Esa1 exist, with Tip60 representing the best-characterized vertebrate counterpart, operating within the Tip60/p400 complexes to perform analogous acetylation and chromatin-regulatory functions.

See also: NuA4 complex, histone acetyltransferases, Tip60, chromatin remodeling, DNA repair.