ACTIVATION AND REPRESSION IN THE NERVOUS-SYSTEM

The mechanisms underlying transcriptional activation and repression ha ve become much clearer. Recent evidence suggests that transcription fa ctors that do not bind DNA directly, the co-activators and co-represso rs, mediate a large number of cell signaling events. Their association with histone acetylases, to mediate activation, or deacetylases, to m ediate repression, provide a model for explaining how gene expression is regulated.