Regulation of gene expression through post-initiation controls

9-19Synthesis of messenger RNA in an eukaryotic cell can be regulated at multiple levels. Although the regulatory processes at the initiation step help in the discrimination between whether or not a gene need to be transcribed in a particular cell at a particular time, the decision to go through with the complete synthesis could still be revised through controls at the succeeding steps of the process. This article reviews the regulatory controls exercised at the transcription elongation step and the factors which participate in this process. Inspite of the plethora of factors contributing to the elongation process, the main catalytic activity is entrusted with the RNA polymerase II, and other factors mainly assist or modify the polymerase to alter its enzymatic efficiency