Molecular mechanism of cytokinin-activated cell division in Arabidopsis
Abstract
Mitogens trigger cell division in animals. In plants, cytokinins, a group of phytohormones derived from adenine, stimulate cell proliferation. Cytokinin signaling is initiated by membrane-associated histidine kinase receptors and transduced through a phosphorelay system. We show that in the Arabidopsis shoot apical meristem (SAM), cytokinin regulates cell division by promoting nuclear shuttling of Myb-domain protein 3R4 (MYB3R4), a transcription factor that activates mitotic gene expression. Newly synthesized MYB3R4 protein resides predominantly in the cytoplasm. At the G2-to-M transition, rapid nuclear accumulation of MYB3R4—consistent with an associated transient peak in cytokinin concentration—feeds a positive feedback loop involving importins and initiates a transcriptional cascade that drives mitosis and cytokinesis. An engineered nuclear-restricted MYB3R4 mimics the cytokinin effects of enhanced cell proliferation and meristem growth.
Additional Information
© 2021 American Association for the Advancement of Science. Received 7 August 2020; accepted 9 February 2021; Published online 25 February 2021. We thank M. Ito, Y. Helariutta, P. Tarr, H. Liu, and the Nottingham Arabidopsis Stock Centre for materials; J. Gruel for help with the computational modeling; K. Jaeger for assistance with DNA library preparation; G. Evans for assisting with the confocal microscopy analysis; and D. Bergmann for helpful discussions. Funding: This work was supported by the Gatsby Charitable Foundation (GAT3395/DAA and GAT3395/PR4B to E.M. and H.J.). The laboratory of E.M. is supported by the Howard Hughes Medical Institute. R.W. received funding from Leverhulme Trust grant RPG-2015-285. The microscopy facility at the Sainsbury Laboratory is supported by the Gatsby Charitable Foundation. Author contributions: W.Y. and E.M. initiated and designed the study. W.Y., S.C., P.R., K.S., A.G., and R.W. performed the experiments. N.K. and H.J. performed modeling and simulation. A.G. analyzed the RNA FISH data. W.Y. and E.M. wrote the manuscript. All authors discussed and commented on the manuscript. Competing interests: The authors declare no competing interests. Data and materials availability: All data are available in the main text or the supplementary materials. Sequencing data are available at the NCBI Gene Expression Omnibus (GEO; www.ncbi.nlm.nih.gov/geo/) under accession number GSE144049. Scripts used for image analysis and modeling are available via the Sainsbury Laboratory Gitlab Repository (https://gitlab.com/slcu/teamhj/publications/yang_etal_2021). Please contact E.M. for material requests.Attached Files
Accepted Version - nihms-1705061.pdf
Supplemental Material - abe2305_MDAR_Reproducibility_Checklist.pdf
Supplemental Material - abe2305_TableS1.xlsx
Supplemental Material - abe2305_TableS2.xlsx
Supplemental Material - abe2305_TableS3.xlsx
Supplemental Material - abe2305_TableS4.xlsx
Supplemental Material - abe2305_Yang_SM.pdf
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Additional details
- PMCID
- PMC8166333
- Eprint ID
- 108235
- Resolver ID
- CaltechAUTHORS:20210301-070217228
- Gatsby Charitable Foundation
- GAT3395/DAA
- Gatsby Charitable Foundation
- GAT3395/PR4B
- Howard Hughes Medical Institute (HHMI)
- Leverhulme Trust
- RPG-2015-285
- Created
-
2021-03-01Created from EPrint's datestamp field
- Updated
-
2022-02-14Created from EPrint's last_modified field
- Caltech groups
- Division of Biology and Biological Engineering (BBE)