Molecular biology I: transcriptional regulation

Whereas the DNA of the cell may be envisaged as the blueprints for a human, it is the processes of transcription and translation that act as the production line to convert these blueprints into the active protein required to produce the complex biological interactions that allow a cell to function. At its very simplest level the process of transcription is concerned with the recruitment of RNA polymerase II (Pol II) to the transcription start site of the target gene: The faster this process occurs then the more transcripts can be produced in a given amount of time and hence the more mRNA is produced to be converted to protein. This rate of Pol II recruitment can be modified through the action of a number of DNA-binding proteins (transcription factors), such as the nuclear receptors that are key sensors for the presence of therapeutic drugs within the cell. In the current article we will examine the techniques available for examining the DNA:protein interactions within the regulatory regions of target genes, which result in the increased recruitment of RNA polymerase II. In addition, we will examine those techniques designed to measure the next stage, the transcription of gene coding regions to make mRNA transcripts.