Gene Transcription Fine Tuned by New Checkpoint Mechanism Alessandro Gardini, Ph.D., assistant professor in the Gene Expression & Regulation Program at The Wistar Institute, in his lab. [Wistar Institute] May 18, 2021 Alessandro Gardini, Ph.D., assistant professor in the Gene Expression & Regulation Program at The Wistar Institute, in his lab. [Wistar Institute] Share Researchers from the Wistar Institute in Philadelphia and the Peter MacCallum Cancer Center in Melbourne, Australia, say they have discovered a new checkpoint mechanism that fine-tunes gene transcription. Cell, a component of the Integrator protein complex tethers the protein phosphatase 2A (PP2A) to the site of transcription allowing it to stop the activity of the RNA polymerase II enzyme (RNAPII).