Current Biology - A Molecular Switch for Initiating Cell Differentiation in Arabidopsis

Current Biology - A Molecular Switch for Initiating Cell Differentiation in Arabidopsis: "A Molecular Switch for Initiating Cell Differentiation in Arabidopsis

Current Biology, Volume 21, Issue 12, 999-1008, 26 May 2011
Copyright © 2011 Elsevier Ltd All rights reserved.
10.1016/j.cub.2011.04.041


Authors
Maite Sanmartín, Michael Sauer, Alfonso Muñoz, Jan Zouhar, Angel Ordóñez, Wilhelmina T.G. van de Ven, Elena Caro, María de la Paz Sánchez, Natasha V. Raikhel, Crisanto Gutiérrez, José J. Sánchez-Serrano, Enrique Rojosend emailSee Affiliations

* Hint: Rollover Authors and Affiliations

Centro Nacional de Biotecnología-CSIC, Cantoblanco, 28049 Madrid, Spain Center for Plant Cell Biology and Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain Corresponding author These authors have contributed equally to this work

* Highlights
* MINIYO is necessary for initiating all events of cell differentiation in Arabidopsis
* MINIYO sustains global levels of transcriptional elongation in differentiating tissues
* Nuclear accumulation of MINIYO is directed to transition cells
* MINIYO accumulation is sufficient to initiate cell differentiation

Summary
Background

The onset of differentiation entails modifying the gene expression state of cells, to allow activation of developmental programs that are maintained repressed in the undifferentiated precursor cells [1,2]. This requires a mechanism to change gene expression on a genome-scale. Recent evidence suggests that in mammalian stem cells, derepression of developmental regulators during differentiation involves a shift from stalled to productive elongation of their transcripts [3,4,5], but factors mediating this shift have not been identified and the evidence remains correlative.
Results

We report the identification of the MINIYO (IYO) gene, a positive regulator of transcriptional elongation that is essential for cells to initiate differentiation in Arabidopsis. IYO interacts with RNA polymerase II and the Elongator complex and is required to sustain global levels of transcriptional elongation activity, specifically in differentiating tissues. Accordingly, IYO is expressed in embryos, meristems, and organ primordia and not in mature tissues. Moreover, differential subcellular protein distribution further refines the domain of IYO function by directing nuclear accumulation, and thus its transcriptional activity, to cells initiating differentiation. Importantly, IYO overexpression induces premature cell differentiation and leads to meristem termination phenotypes.
Conclusions

These findings identify IYO as a necessary and sufficient factor for initiating differentiation in Arabidopsis and suggest that the targeted nuclear accumulation of IYO functions as a transcriptional switch for this fate transition.

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