MYCN-dependent Transcription Termination and Stress Resilience of Transcription

• Applicant: Professor Dr. Martin Eilers
• Subject Area: Cell Biology ; Biochemistry
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 438596161

• Final Report Year: 2025

Final Report Abstract

MYCN is one of three genes in the MYC family and is a driving oncogene in many neuroendocrine tumor entities. It encodes a nuclear protein that displays many features of a transcription factor and binds globally to active promoters and many enhancers. A large body of literature documents that MYCN, like its counterpart MYC, can both positively and negatively affect the expression of many genes and potentially increase global transcription rates. However, it has been difficult to explain the pervasive role of MYCN in tumorigenesis in terms of changes in the expression of its target genes because MYCN has very weak effects on the expression of the vast majority of genes with MYCN-bound promoters. At the beginning of the project, we had identified the MYCN interactome and studied its dynamics during the cell cycle. This suggested that MYCN proteins may coordinate transcription elongation with DNA replication. We had also found that MYCN can promote premature transcription termination when RNA polymerase II (RNAPII) stalls. The work in this project led to the observation that MYCN proteins exist in a dynamic equilibrium of two very different states: first, the canonical DNA-bound state, and second, an RNA-bound state, as MYCN translocates to nascent intronic RNA and the RNA degradation machinery to intronic RNA when transcription elongation or co-transcriptional steps in RNA processing are perturbed. We found that MYCN is a direct RNA binding protein and that MYCN mutants that are unable to bind RNA can still promote cell growth and enhance transcription but have defects in coordinating transcription with DNA replication and the resulting cells are hypersensitive to DNA damaging agents. Together with work on MYC that has emerged from the work on MYCN, our data strongly support a model in which relief of transcriptional stress is an important oncogenic function of MYCN. Building on this work, we have now also identified a druggable MYCN-dependent transcription termination pathway and shown that targeting this pathway eliminates MYCN-driven tumor growth in patient-derived xenograft models.

Publications

• Ubiquitylation of MYC couples transcription elongation with double-strand break repair at active promoters. Molecular Cell, 81(4), 830-844.e13.
  Endres, Theresa; Solvie, Daniel; Heidelberger, Jan B.; Andrioletti, Valentina; Baluapuri, Apoorva; Ade, Carsten P.; Muhar, Matthias; Eilers, Ursula; Vos, Seychelle M.; Cramer, Patrick; Zuber, Johannes; Beli, Petra; Popov, Nikita; Wolf, Elmar; Gallant, Peter & Eilers, Martin
  
• MYC multimers shield stalled replication forks from RNA polymerase. Nature, 612(7938), 148-155.
  Solvie, Daniel; Baluapuri, Apoorva; Uhl, Leonie; Fleischhauer, Daniel; Endres, Theresa; Papadopoulos, Dimitrios; Aziba, Amel; Gaballa, Abdallah; Mikicic, Ivan; Isaakova, Ekaterina; Giansanti, Celeste; Jansen, Jennifer; Jungblut, Marvin; Klein, Teresa; Schülein-Völk, Christina; Maric, Hans; Doose, Sören; Sauer, Markus; Beli, Petra ... & Eilers, Martin
  
• MYCN recruits the nuclear exosome complex to RNA polymerase II to prevent transcription-replication conflicts. Molecular Cell, 82(1), 159-176.e12.
  Papadopoulos, Dimitrios; Solvie, Daniel; Baluapuri, Apoorva; Endres, Theresa; Ha, Stefanie Anh; Herold, Steffi; Kalb, Jacqueline; Giansanti, Celeste; Schülein-Völk, Christina; Ade, Carsten Patrick; Schneider, Cornelius; Gaballa, Abdallah; Vos, Seychelle; Fischer, Utz; Dobbelstein, Matthias; Wolf, Elmar & Eilers, Martin
  
• Association with TFIIIC limits MYCN localisation in hubs of active promoters and chromatin accumulation of non-phosphorylated RNA polymerase II. eLife, 13.
  Vidal, Raphael; Leen, Eoin; Herold, Steffi; Müller, Mareike; Fleischhauer, Daniel; Schülein-Völk, Christina; Papadopoulos, Dimitrios; Röschert, Isabelle; Uhl, Leonie; Ade, Carsten P.; Gallant, Peter; Bayliss, Richard; Eilers, Martin & Büchel, Gabriele
  
• PAF1c links S-phase progression to immune evasion and MYC function in pancreatic carcinoma. Nature Communications, 15(1).
  Gaballa, Abdallah; Gebhardt-Wolf, Anneli; Krenz, Bastian; Mattavelli, Greta; John, Mara; Cossa, Giacomo; Andreani, Silvia; Schülein-Völk, Christina; Montesinos, Francisco; Vidal, Raphael; Kastner, Carolin; Ade, Carsten P.; Kneitz, Burkhard; Gasteiger, Georg; Gallant, Peter; Rosenfeldt, Mathias; Riedel, Angela & Eilers, Martin
  
• The MYCN oncoprotein is an RNA-binding accessory factor of the nuclear exosome targeting complex. Molecular Cell, 84(11), 2070-2086.e20.
  Papadopoulos, Dimitrios; Ha, Stefanie Anh; Fleischhauer, Daniel; Uhl, Leonie; Russell, Timothy J.; Mikicic, Ivan; Schneider, Katharina; Brem, Annika; Valanju, Omkar Rajendra; Cossa, Giacomo; Gallant, Peter; Schuelein-Voelk, Christina; Maric, Hans Michael; Beli, Petra; Büchel, Gabriele; Vos, Seychelle M. & Eilers, Martin