2. Academic Validation
  3. The tRNA pseudouridine synthase TruB1 regulates the maturation of let-7 miRNA

The tRNA pseudouridine synthase TruB1 regulates the maturation of let-7 miRNA

  • EMBO J. 2020 Oct 15;39(20):e104708. doi: 10.15252/embj.2020104708.
Ryota Kurimoto 1,  Tomoki Chiba 1,  Yoshiaki Ito 1 2,  Takahide Matsushima 1,  Yuki Yano 1,  Kohei Miyata 3,  Yuka Yashiro 4,  Tsutomu Suzuki 5,  Kozo Tomita 4,  Hiroshi Asahara 1 6
Affiliations

Affiliations

  • 1 Department of Systems BioMedicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
  • 2 Research Core, Research Facility Cluster, Institute of Research, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
  • 3 Department Obstetrics and Gynecology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
  • 4 Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan.
  • 5 Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo, Japan.
  • 6 Department of Molecular and Experimental Medicine, The Scripps Research Institute, San Diego, CA, USA.
PMID: 32926445 DOI: 10.15252/embj.2020104708
Abstract

Let-7 is an evolutionary conserved MicroRNA that mediates post-transcriptional gene silencing to regulate a wide range of biological processes, including development, differentiation, and tumor suppression. Let-7 biogenesis is tightly regulated by several RNA-binding proteins, including Lin28A/B, which represses let-7 maturation. To identify new regulators of let-7, we devised a cell-based functional screen of RNA-binding proteins using a let-7 sensor luciferase reporter and identified the tRNA pseudouridine synthase, TruB1. TruB1 enhanced maturation specifically of let-7 family members. Rather than inducing pseudouridylation of the miRNAs, high-throughput Sequencing crosslinking immunoprecipitation (HITS-CLIP) and biochemical analyses revealed direct binding between endogenous TruB1 and the stem-loop structure of pri-let-7, which also binds Lin28A/B. TruB1 selectively enhanced the interaction between pri-let-7 and the microprocessor DGCR8, which mediates miRNA maturation. Finally, TruB1 suppressed cell proliferation, which was mediated in part by let-7. Altogether, we reveal an unexpected function for TruB1 in promoting let-7 maturation.

Keywords

RNA-binding protein; TruB1; let-7; microRNA; pseudouridine.

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