Telethon Institute of Genetics and Medicine, via P. Castellino 111, 80131 Naples, Italy. piacosma@tigem.it
Activators, chromatin-modifying enzymes, and basal transcription factors unite to activate genes, but are recruited in a precise order to promoters. The timing of the activation of transcription and the ordered recruitment of factors to promoters are the engines which, at the right moment and for the right length of time, drive the transcriptional regulation of each gene throughout the life of a cell.