ABSTRACT
This chapter looks at some of the elements of transcription regulation. It discusses epigenetic mechanisms—transcription regulatory mechanisms that involve either Deoxyribonucleic acid (DNA) or histone covalent modifications. Important in transcriptional regulation are also enhancer elements that often are located distant to the transcription start site. Critical molecular players in the regulation of transcription are the specific transcription factors, proteins that bind to a subset of genes, rather than all of them. These transcription factors may act either as repressors or activators of transcription. Adding to the complexity of transcription initiation and regulation is the fact that many genes have more than one transcription start site, and the selection of the start site is subject to control. Each of the transcription factors typically recognizes DNA in a sequence-specific manner. The action of a transcription factor is dependent on its recognition of a site in DNA.
