SUMMARY PARAGRAPH for ELP3
ELP3 encodes a histone acetyltransferase (HAT) that is part of the six-subunit Elongator complex, which is a major component of the RNA polymerase II holoenzyme responsible for transcriptional elongation (1, 2, 4). Elongator contains two discrete subcomplexes, one consisting of Iki3p/Elp1p, Elp2p, and Elp3p, and the other consisting of Elp4p, Iki1p/Elp5p, and Elp6p (9, 10). Elongator binds to both naked and nucleosomal DNA, can acetylate both core histones and nucleosomal substrates, and plays a role in chromatin remodeling (11, 5). Its activity is directed specifically toward the amino-terminal tails of histone H3 and H4, with the predominant acetylation sites being lysine-14 of histone H3 and lysine-8 of histone H4 (5). Besides its role as a HAT, Elp3p assists subunit communication within Elongator by mediating the protein-protein interactions of Elp2p-Kti12p, Elp2p-Iki1p/Elp5p, Elp2p-Iki3p/Elp1p, and Kti12p-Iki1p/Elp5p (12).
Of the six Elongator subunits, only Iki1p/Elp5p is essential for growth, and deletion of the other individual subunits causes significantly altered mRNA expression levels for many genes (10). Cells lacking Elp3p experience hypoacetylation of histones H3 and H4 in chromatin (5, 13), whereas cells lacking both Gcn5p and Elp3p exhibit derepression of subtelomerically-located genes, suggesting a spread of Sir3p into subtelomeric DNA from the tip of the telomere (14). Disruption of ELP3 also confers resistance to the Kluyveromyces lactis zymotoxin (6), and a reduced sensitivity to the Pichia inositovora toxin (15).
Last updated: 2004-05-06