Histone acetyl transferases: a role in DNA repair and DNA replication.

In eukaryotic cells DNA is associated with proteins to form a complex known as chromatin. The dominant proteins within this chromatin complex are the histones, which are subject to a wide variety of covalent and reversible posttranslational modifications such as acetylation. A specialized family of enzymes, the histone acetyl transferases, catalyzes the transfer of acetyl groups from their cosubstrate acetyl-coenzyme A to lysine residues of histones. Acetylation of histone N-terminal lysine residues induces chromosomal changes and results in the loss of chromosomal repression that allows the successful transcription of the underlying genes. Analogously, in DNA repair and also DNA replication the chromosomal repression is thought to be relieved by such mechanisms. Recently several publications have provided evidence that histone acetyl transferases also modify nonhistone proteins and thereby regulate their activities. This review discusses various aspects of histone acetyl transferases and summarizes recent findings which suggest a role for histone acetyl transferases in DNA repair and DNA replication.