Charakterisierung von Faktoren und Mechanismen der Translationskontrolle von TOP-mRNAs
Biochemie
Zellbiologie
Zusammenfassung der Projektergebnisse
Investigating the molecular basis of the TOP-response: We employed gradient profiling by sequencing (Grad-seq) to globally analyse translation efficiency and changes in the cellular mRNP composition in parallel upon mTOR inactivation in nutrient starvation conditions. Grad-seq combines biochemical separation of RNA-protein complexes from cellular extracts by gradient centrifugation followed by RNA sequencing (RNA- seq) of individual gradient fractions. Challenging previous findings, Grad-seq shows 5’-TOP mRNAs to accumulate primarily in monosome fractions upon starvation, while bulk mRNA translation rates are unchanged. In addition, unlike most other cellular mRNAs, whose transcript levels decrease under starvation conditions, the 5’TOP mRNA population remains stable. Moreover, we show that 5’TOP mRNAs are actively translated in monosomes during starvation. This mode, which we refer to as “baseline translation”, requires functional LARP1, is maintained over long periods of mTOR inhibition, and correlates with the previously reported stabilization of 5’TOP mRNAs by LARP1. Baseline translation reconciles many of the apparently contradictory key features of the TOP response, as it explains how mRNAs that are translationally downregulated can be stabilized at the same time. Our results also provide mechanistic insights into translation in monosomes, which has also been observed in yeast. The role of the RNA-helicases in mRNA homeostasis: RNA helicases constitute a large protein family that use ATP hydrolysis to remodel substrate RNAs and RNA-protein complexes (RNPs). Structural and functional studies have provided detailed insight into the mechanism of RNA helicases’ activities on their targets but how they identify their substrates and what renders specificity to their cellular role remain mostly elusive. Interestingly, the translation machinery appears to be a hot spot for RNA helicase activity and loss of or defects in various RNA helicases have been implicated in human diseases, particularly, those affecting the nervous system. In this project we will investigate the ribosomeassociated RNA helicase IGHMBP2, which is genetically linked to the motoneuron disease SMARD12. Our work has shown that IGHMBP2 regulates a distinct set of target-mRNAs with short GC-rich highly structured 5’ UTRs, thus constituting an mRNA regulon. Our data indicate that this regulon modulates the post-transcriptional gene expression program of the cell. It is our goal to uncover the molecular basis of this helicase-driven post-transcriptional gene regulation and gain insight into the ethology of SMARD1.
Projektbezogene Publikationen (Auswahl)
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Deciphering the mRNP Code: RNA-Bound Determinants of Post-Transcriptional Gene Regulation. Trends in Biochemical Sciences, 42(5), 369-382.
Gehring, Niels H.; Wahle, Elmar & Fischer, Utz
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Crystal Structure of a Variant PAM2 Motif of LARP4B Bound to the MLLE Domain of PABPC1. Biomolecules, 10(6), 872.
Grimm, Clemens; Pelz, Jann-Patrick; Schneider, Cornelius; Schäffler, Katrin & Fischer, Utz
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Grad-seq shines light on unrecognized RNA and protein complexes in the model bacterium Escherichia coli. Nucleic Acids Research, 48(16), 9301-9319.
Hör, Jens; Di Giorgio, Silvia; Gerovac, Milan; Venturini, Elisa; Förstner, Konrad U & Vogel, Jörg
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Grad‐seq in a Gram‐positive bacterium reveals exonucleolytic sRNA activation in competence control. The EMBO Journal, 39(9).
Hör, Jens; Garriss, Geneviève; Di Giorgio, Silvia; Hack, Lisa‐Marie; Vanselow, Jens T; Förstner, Konrad U; Schlosser, Andreas; Henriques‐Normark, Birgitta & Vogel, Jörg
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Genotype–phenotype correlations and novel molecular insights into the DHX30-associated neurodevelopmental disorders. Genome Medicine, 13(1).
Mannucci, Ilaria; Dang, Nghi D. P.; Huber, Hannes; Murry, Jaclyn B.; Abramson, Jeff; Althoff, Thorsten; Banka, Siddharth; Baynam, Gareth; Bearden, David; Beleza-Meireles, Ana; Benke, Paul J.; Berland, Siren; Bierhals, Tatjana; Bilan, Frederic; Bindoff, Laurence A.; Braathen, Geir Julius; Busk, Øyvind L.; Chenbhanich, Jirat; Denecke, Jonas; ... & Lessel, Davor
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An unusual mode of baseline translation adjusts cellular protein synthesis capacity to metabolic needs. Cell Reports, 41(2), 111467.
Schneider, Cornelius; Erhard, Florian; Binotti, Beyenech; Buchberger, Alexander; Vogel, Jörg & Fischer, Utz
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hnRNP R negatively regulates transcription by modulating the association of P‐TEFb with 7SK and BRD4. EMBO reports, 23(9).
Ji, Changhe; Deng, Chunchu; Antor, Katharina; Bischler, Thorsten; Schneider, Cornelius; Fischer, Utz; Sendtner, Michael & Briese, Michael
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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
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Cytosolic Ptbp2 modulates axon growth in motoneurons through axonal localization and translation of Hnrnpr. Nature Communications, 14(1).
Salehi, Saeede; Zare, Abdolhossein; Prezza, Gianluca; Bader, Jakob; Schneider, Cornelius; Fischer, Utz; Meissner, Felix; Mann, Matthias; Briese, Michael & Sendtner, Michael
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RNA helicase IGHMBP2 regulates THO complex to ensure cellular mRNA homeostasis. Cell Reports, 43(2), 113802.
Prusty, Archana Bairavasundaram; Hirmer, Anja; Sierra-Delgado, Julieth Andrea; Huber, Hannes; Guenther, Ulf-Peter; Schlosser, Andreas; Dybkov, Olexandr; Yildirim, Ezgi; Urlaub, Henning; Meyer, Kathrin C.; Jablonka, Sibylle; Erhard, Florian & Fischer, Utz
