TY - JOUR T1 - The human RNA polymerase I structure reveals an HMG-like docking domain specific to metazoans JF - Life Science Alliance JO - Life Sci. Alliance DO - 10.26508/lsa.202201568 VL - 5 IS - 11 SP - e202201568 AU - Julia L Daiß AU - Michael Pilsl AU - Kristina Straub AU - Andrea Bleckmann AU - Mona Höcherl AU - Florian B Heiss AU - Guillermo Abascal-Palacios AU - Ewan P Ramsay AU - Katarina Tlučková AU - Jean-Clement Mars AU - Torben Fürtges AU - Astrid Bruckmann AU - Till Rudack AU - Carrie Bernecky AU - Valérie Lamour AU - Konstantin Panov AU - Alessandro Vannini AU - Tom Moss AU - Christoph Engel Y1 - 2022/11/01 UR - https://www.life-science-alliance.org/content/5/11/e202201568.abstract N2 - Transcription of the ribosomal RNA precursor by RNA polymerase (Pol) I is a major determinant of cellular growth, and dysregulation is observed in many cancer types. Here, we present the purification of human Pol I from cells carrying a genomic GFP fusion on the largest subunit allowing the structural and functional analysis of the enzyme across species. In contrast to yeast, human Pol I carries a single-subunit stalk, and in vitro transcription indicates a reduced proofreading activity. Determination of the human Pol I cryo-EM reconstruction in a close-to-native state rationalizes the effects of disease-associated mutations and uncovers an additional domain that is built into the sequence of Pol I subunit RPA1. This “dock II” domain resembles a truncated HMG box incapable of DNA binding which may serve as a downstream transcription factor–binding platform in metazoans. Biochemical analysis, in situ modelling, and ChIP data indicate that Topoisomerase 2a can be recruited to Pol I via the domain and cooperates with the HMG box domain–containing factor UBF. These adaptations of the metazoan Pol I transcription system may allow efficient release of positive DNA supercoils accumulating downstream of the transcription bubble. ER -