TY - JOUR

T1 - Concerted expression of a cell cycle regulator and a metabolic enzyme from a bicistronic transcript in plants

AU - Lorenzo-Orts, Laura

AU - Witthoeft, Janika

AU - Deforges, Jules

AU - Martinez, Jacobo

AU - Loubéry, Sylvain

AU - Placzek, Aleksandra

AU - Poirier, Yves

AU - Hothorn, Ludwig A.

AU - Jaillais, Yvon

AU - Hothorn, Michael

N1 - Funding Information: The authors thank J. M. Perez-Perez for sending the CYCB1;1-GFP line, A. Wachter for lba1 and upf3-1 seeds, and R. Ulm, A. Wachter and N. Geldner for critical reading of the manuscript. This project was supported by an ERC starting grant from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007–2013)/ERC Grant Agreement no. 310856, the Max Planck Society, the European Molecular Biology Organisation (EMBO) Young Investigator Programme (to M.H.), the Howard Hughes Medical Institute (International Research Scholar Award to M.H.) and the Swiss National Fund Sinergia grant (CRSII3-154471 to Y.P.).

PY - 2019/2

Y1 - 2019/2

N2 - Eukaryotic mRNAs frequently contain upstream open reading frames (uORFs), encoding small peptides that may control translation of the main ORF (mORF). Here, we report the characterization of a distinct bicistronic transcript in Arabidopsis. We analysed loss-of-function phenotypes of the inorganic polyphosphatase TRIPHOSPHATE TUNNEL METALLOENZYME 3 (AtTTM3), and found that catalytically inactive versions of the enzyme could fully complement embryo and growth-related phenotypes. We could rationalize these puzzling findings by characterizing a uORF in the AtTTM3 locus encoding CELL DIVISION CYCLE PROTEIN 26 (CDC26), an orthologue of the cell cycle regulator. We demonstrate that AtCDC26 is part of the plant anaphase promoting complex/cyclosome (APC/C), regulates accumulation of APC/C target proteins and controls cell division, growth and embryo development. AtCDC26 and AtTTM3 are translated from a single transcript conserved across the plant lineage. While there is no apparent biochemical connection between the two gene products, AtTTM3 coordinates AtCDC26 translation by recruiting the transcript into polysomes. Our work highlights that uORFs may encode functional proteins in plant genomes.

AB - Eukaryotic mRNAs frequently contain upstream open reading frames (uORFs), encoding small peptides that may control translation of the main ORF (mORF). Here, we report the characterization of a distinct bicistronic transcript in Arabidopsis. We analysed loss-of-function phenotypes of the inorganic polyphosphatase TRIPHOSPHATE TUNNEL METALLOENZYME 3 (AtTTM3), and found that catalytically inactive versions of the enzyme could fully complement embryo and growth-related phenotypes. We could rationalize these puzzling findings by characterizing a uORF in the AtTTM3 locus encoding CELL DIVISION CYCLE PROTEIN 26 (CDC26), an orthologue of the cell cycle regulator. We demonstrate that AtCDC26 is part of the plant anaphase promoting complex/cyclosome (APC/C), regulates accumulation of APC/C target proteins and controls cell division, growth and embryo development. AtCDC26 and AtTTM3 are translated from a single transcript conserved across the plant lineage. While there is no apparent biochemical connection between the two gene products, AtTTM3 coordinates AtCDC26 translation by recruiting the transcript into polysomes. Our work highlights that uORFs may encode functional proteins in plant genomes.

UR - http://www.scopus.com/inward/record.url?scp=85061296414&partnerID=8YFLogxK

U2 - 10.1038/s41477-019-0358-3

DO - 10.1038/s41477-019-0358-3

M3 - Article

C2 - 30737513

AN - SCOPUS:85061296414

VL - 5

SP - 184

EP - 193

JO - Nature plants

JF - Nature plants

SN - 2055-0278

IS - 2

ER -