There are various proteins callled as transcription factors which regulate the process of transcription. In addition to the general transcription factors, other transcription factors can bind to the promoter to regulate gene transcription. In some eukaryotic genes, there are regions that help increase or enhance transcription. These are enhancers which may be located upstream or downstream of a gene to be regulated. Then there are transcriptional repressors that can can bind to promoter or enhancer regions and block transcription.