“…Typically, the conditional rpb1-1 mutant ( 43) is used to interrogate the role of Pol II in phenomena such as chromatin occupancy of a transcription-associated protein. This approach is not ideal as Pol II occupancy is only moderately (2-to 3-fold) reduced at actively transcribing genes following a 90 min shift to the non-permissive temperature (37°C) (e.g., (44) ). By contrast, HD pretreatment followed by a 7.5 min shift to 39°C, as described here, results in close to 100% loss of Pol II occupancy within 10 min at both constitutively and inducibly transcribed genes.…”