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.
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The authors especially thank Philip Gunkel for his contribution. We thank all past and present members of the Engel lab, Achim Griesenbeck, Colyn Crane- Robinson, Christophe Lotz, Marlene Vayssieres, Klaus Grasser, Herbert Tschochner, and Philipp Milkereit for help and discussion; Gerhard Lehmann and Nobert Eichner for IT support; Joost Zomerdijk for UBF-constructs, Volker Cordes for the Hela P2 cell line; Remco Sprangers for shared cell culture; Dina Grohmann and the Archaea Center for fermentation; and Thomas Dresselhaus for access to fluorescence microscopes. This work was in part supported by the Emmy-Noether Programm (DFG grant no. EN 1204/1-1 to C Engel) of the German Research Council and Collaborative Research Center 960 (TP-A8 to C Engel).
Daiß JL, Pilsl M, Straub K, et al. The human RNA polymerase I structure reveals an HMG-like docking domain specific to metazoans. Life Science Alliance. 2022;5(11). doi:10.26508/lsa.202201568
Daiß, J. L., Pilsl, M., Straub, K., Bleckmann, A., Höcherl, M., Heiss, F. B., … Engel, C. (2022). The human RNA polymerase I structure reveals an HMG-like docking domain specific to metazoans. Life Science Alliance. Life Science Alliance. https://doi.org/10.26508/lsa.202201568
Daiß, Julia L, Michael Pilsl, Kristina Straub, Andrea Bleckmann, Mona Höcherl, Florian B Heiss, Guillermo Abascal-Palacios, et al. “The Human RNA Polymerase I Structure Reveals an HMG-like Docking Domain Specific to Metazoans.” Life Science Alliance. Life Science Alliance, 2022. https://doi.org/10.26508/lsa.202201568.
J. L. Daiß et al., “The human RNA polymerase I structure reveals an HMG-like docking domain specific to metazoans,” Life Science Alliance, vol. 5, no. 11. Life Science Alliance, 2022.
Daiß JL, Pilsl M, Straub K, Bleckmann A, Höcherl M, Heiss FB, Abascal-Palacios G, Ramsay EP, Tluckova K, Mars J-C, Fürtges T, Bruckmann A, Rudack T, Bernecky C, Lamour V, Panov K, Vannini A, Moss T, Engel C. 2022. The human RNA polymerase I structure reveals an HMG-like docking domain specific to metazoans. Life Science Alliance. 5(11), e202201568.
Daiß, Julia L., et al. “The Human RNA Polymerase I Structure Reveals an HMG-like Docking Domain Specific to Metazoans.” Life Science Alliance, vol. 5, no. 11, e202201568, Life Science Alliance, 2022, doi:10.26508/lsa.202201568.
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