1. Academic Validation
  2. Characterisation of the biflavonoid hinokiflavone as a pre-mRNA splicing modulator that inhibits SENP

Characterisation of the biflavonoid hinokiflavone as a pre-mRNA splicing modulator that inhibits SENP

  • Elife. 2017 Sep 8;6:e27402. doi: 10.7554/eLife.27402.
Andrea Pawellek 1 Ursula Ryder 1 Triin Tammsalu 1 Lewis J King 2 Helmi Kreinin 2 Tony Ly 1 Ronald T Hay 1 Richard C Hartley 2 Angus I Lamond 1
Affiliations

Affiliations

  • 1 Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom.
  • 2 WestCHEM, School of Chemistry, University of Glasgow, Glasgow, United Kingdom.
Abstract

We have identified the plant biflavonoid hinokiflavone as an inhibitor of splicing in vitro and modulator of alternative splicing in cells. Chemical synthesis confirms hinokiflavone is the active molecule. Hinokiflavone inhibits splicing in vitro by blocking spliceosome assembly, preventing formation of the B complex. Cells treated with hinokiflavone show altered subnuclear organization specifically of splicing factors required for A complex formation, which relocalize together with SUMO1 and SUMO2 into enlarged nuclear speckles containing polyadenylated RNA. Hinokiflavone increases protein SUMOylation levels, both in in vitro splicing reactions and in cells. Hinokiflavone also inhibited a purified, E. coli expressed SUMO Protease, SENP1, in vitro, indicating the increase in SUMOylated proteins results primarily from inhibition of de-SUMOylation. Using a quantitative proteomics assay we identified many SUMO2 sites whose levels increased in cells following hinokiflavone treatment, with the major targets including six proteins that are components of the U2 snRNP and required for A complex formation.

Keywords

RNA splicing; SENP1; SUMO; U2 snRNP; biochemistry; hinokiflavone; none.

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