ABSTRACT
Transcriptional regulation occurs via transcription factors that bind to short control elements associated with the target genes and then interact with each other and with the transcription initiation complex to increase or decrease the rate of transcription of the target gene. Many transcription factors bind to control sequences within a few hundred base pairs of the protein-coding gene being regulated. Transcriptional regulation in a eukaryotic cell is mediated by transcription factors which recognize and bind to short regulatory DNA sequences associated with the gene. In most cases, the transcription factors in eukaryotes that bind to enhancer or promoter sequences are activator proteins that induce transcription. Gene repressor proteins that inhibit the transcription of specific genes in eukaryotes also exist. They may act by binding either to control elements within the promoter region near the gene or at sites located a long distance away from the gene, called silencers.
