The yeast regulator of transcription protein Rtr1lacks an active site and phosphatase activity

摘要

The activity of RnA polymerase II (Pol II) is controlled in part by the phosphorylation stateof the C-terminal domain (CTD) of its largest subunit. Recent reports have suggested thatyeast regulator of transcription protein, Rtr1, and its human homologue RPAP2, possess PolII CTD ser5 phosphatase activity. Here we report the crystal structure of Kluyveromyces lactisRtr1, which reveals a new type of zinc finger protein and does not have any close structuralhomologues. Importantly, the structure does not show evidence of an active site, and extensiveexperiments to demonstrate its CTD phosphatase activity have been unsuccessful, suggestingthat Rtr1 has a non-catalytic role in CTD dephosphorylation.