RNA polymerase II C-terminal domain: Tethering transcription to transcript and template

The RNA polymerase II (Pol II) C-terminal domain (CTD) is a repetitive disordered domain that extends from the catalytic core of the enzyme. This tail domain is heavily modified by phosphorylation, glycosylation, and proline isomerization. In addition to the enzymes that modify the tail a number of RNA processing factors and chromatin modification factors interact with the CTD. Thus, this domain acts as a tether to bring into close proximity the machinery necessary to synthesize and process Pol II transcripts. Gene-specific aspects of CTD function will be discussed in accompanying reviews by Jeronimo et al. and Eick and Geyer. To set the stage for discussing the CTD the evolution of this domain is also considered. Genetic and gene expression effects of altering the CTD will then be considered.