Control of histone modifications.

A role for histone modifications in transcription processes and the remodeling of chromatin structure has been established. This review highlights the recent advances made in studies on histone acetyltransferases, histone deacetylases, histone kinases, and protein phosphatases, as well as their roles in transcriptional activation and repression. Coactivators with histone acetyltransferase activity stimulate transcription, whereas corepressors with histone deacetylase activity repress transcription. Families of histone acetyltransferases and deacetylases have been identified. We have learned that their substrates are not limited to histones but also include transcription factors and architectural proteins. Studies on the composition of multiprotein complexes with histone acetyltransferase or histone deacetylase have revealed mechanisms by which these complexes are recruited to specific genomic sites that are transcriptionally active, silenced, or being repaired. A new and exciting development, presented in this review, is the role of signal transduction pathways in the phosphorylation of histone H3 and the expression of immediate-early genes. J. Cell. Biochem. Suppls. 32/33:141-148, 1999. Copyright 1999 Wiley-Liss, Inc.