Transcriptional control by arginine methylation
Final Report Abstract
The terminated research project concentrated on three members of the Protein Arginine Methyltransferase (PRMT) enzyme family: PRMT1, PRMT4 and PRMT6. We aimed to characterize novel interaction partners and substrates of the selected PRMTs, to define their individual cellular roles in transcriptional regulation as well as the non-transcriptional processes. In the first/previous funding period we had identified several so far unknown interaction partners as well as substrates of the selected PRMTs using various affinity-purification strategies coupled to mass spectrometry. In the second (meanwhile terminated) funding period, we studied in depth the cellular implications of these newly discovered protein-protein interactions and methylation events. In the first project part, we characterized the stress sensor protein p14 ARF as a novel interaction partner and substrate of PRMT1. We found that PRMT1 functions as a tumor suppressor in cellular stress situations, e.g. genotoxic stress, and fosters p53-independent apoptosis by arginine methylation of p14 ARF. In the second project part, we investigated the arginine methylation of c-Myb by PRMT1 and PRMT4 and how this influences the gene-regulatory function of c-Myb in acute myeloid leukemia (AML) cells. The third project part focused on PRMT6. Using published crystal structures, proteinprotein docking approaches and methyltransferase motif analysis by mass spectrometry (MT-MAMS), we characterized in cooperation with the group of Dr. Gene Hart-Smith (Macquarie University, Sydney) the substrate specificity of PRMT6. In agreement with its substrate preference, we found in further studies that PRMT6 interacts with numerous RNA binding proteins and splicing factors, such as several HNRNP proteins, NF45/ILF2 and NF90/ILF3. We investigated the role of PRMT6 in mRNA processing of pluripotent as well as neuronal differentiating NT2/D1 cells and detected that PRMT6 globally influences alternative splicing, primarily of cassette exons and mainly in a histone methylation-independent fashion, thereby contributing to pluripotency and neuronal identity. Altogether, this research funding enabled the identification of novel interaction partners, substrates and functions of the selected PRMT members and revealed that PRMT1, PRMT4 and PRMT6, respectively, are involved in cancerrelevant signaling processes and regulate gene expression on the transcriptional as well as posttranscriptional level.
Publications
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Assaying epigenome functions of PRMTs and their substrates. Methods, 175, 53-65.
Rakow, Sinja; Pullamsetti, Soni Savai; Bauer, Uta-Maria & Bouchard, Caroline
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PRMT1 promotes the tumor suppressor function of p14 ARF and is indicative for pancreatic cancer prognosis. The EMBO Journal, 40(13).
Repenning, Antje; Happel, Daniela; Bouchard, Caroline; Meixner, Marion; Verel‐Yilmaz, Yesim; Raifer, Hartmann; Holembowski, Lena; Krause, Eberhard; Kremmer, Elisabeth; Feederle, Regina; Keber, Corinna U.; Lohoff, Michael; Slater, Emily P.; Bartsch, Detlef K. & Bauer, Uta‐Maria
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Systematic investigation of PRMT6 substrate recognition reveals broad specificity with a preference for an RG motif or basic and bulky residues. The FEBS Journal, 288(19), 5668-5691.
Hamey, Joshua J.; Rakow, Sinja; Bouchard, Caroline; Senst, Johanna M.; Kolb, Peter; Bauer, Uta‐Maria; Wilkins, Marc R. & Hart‐Smith, Gene
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MeCP2 heterochromatin organization is modulated by arginine methylation and serine phosphorylation. Frontiers in Cell and Developmental Biology, 10.
Schmidt, Annika; Frei, Jana; Poetsch, Ansgar; Chittka, Alexandra; Zhang, Hui; Aßmann, Chris; Lehmkuhl, Anne; Bauer, Uta-Maria; Nuber, Ulrike A. & Cardoso, M. Cristina
