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Mol. Cells 2009; 28(4): 375-382

Published online September 30, 2009

https://doi.org/10.1007/s10059-009-0132-x

© The Korean Society for Molecular and Cellular Biology

RNAi Suppression of RPN12a Decreases the
Expression of Type-A ARRs, Negative Regula-tors
of Cytokinin Signaling Pathway, in Arabidopsis

Moon Young Ryu, Seok Keun Cho, and Woo Taek Kim

Received: July 2, 2009; Revised: August 5, 2009; Accepted: August 6, 2009

Abstract

The 26S proteasome is a 2-MDa complex with a central role in protein turn over. The 26S proteasome is comprised of one 20S core particle and two 19S regulatory particles (RPs). The RPN12a protein, a non-ATPase subunit of the 19S RP, was previously shown to be involved in cytokinin signaling in Arabidopsis. To further investigate cellular roles of RPN12a, RNAi transgenic plants of RPN12a were constructed. As expected, the 35S:RNAi-RPN12a plants showed cytokinin signaling defective phenotypes, including abnormal formation of leaves and inflorescences. Furthermore, RNAi knock-down transgenic plants exhibited additional unique phenotypes, including concave and heart-shape cotyledons, triple cotyledons, irregular and clustered guard cells, and defects in phyllotaxy, all of which are typical for defective cytokinin signaling. We next examined the mRNA level of cytokinin signaling compo-nents, including type-A ARRs, type-B ARRs, and CRFs. The expression of type-A ARRs, encoding negative regulators of cytokinin signaling, was markedly reduced in 35S:RNAi-RPN12a transgenic plants relative to that in wild type plants, while type-B ARRs and CRFs were unaffected. Our results also indicate that in vivo stability of the ARR5 protein, a negative regulator of cytokinin signaling, is mediated by the 26S proteasome complex. These results suggest that RPN12a participates in feedback inhibitory mechanism of cytokinin signaling through modulation of the abundance of ARR5 protein in Arabidopsis.

Keywords 26S proteasome complex, Arabidopsis, cytokinin signaling, RNAi suppression, RPN12a

Article

Research Article

Mol. Cells 2009; 28(4): 375-382

Published online October 31, 2009 https://doi.org/10.1007/s10059-009-0132-x

Copyright © The Korean Society for Molecular and Cellular Biology.

RNAi Suppression of RPN12a Decreases the
Expression of Type-A ARRs, Negative Regula-tors
of Cytokinin Signaling Pathway, in Arabidopsis

Moon Young Ryu, Seok Keun Cho, and Woo Taek Kim

Received: July 2, 2009; Revised: August 5, 2009; Accepted: August 6, 2009

Abstract

The 26S proteasome is a 2-MDa complex with a central role in protein turn over. The 26S proteasome is comprised of one 20S core particle and two 19S regulatory particles (RPs). The RPN12a protein, a non-ATPase subunit of the 19S RP, was previously shown to be involved in cytokinin signaling in Arabidopsis. To further investigate cellular roles of RPN12a, RNAi transgenic plants of RPN12a were constructed. As expected, the 35S:RNAi-RPN12a plants showed cytokinin signaling defective phenotypes, including abnormal formation of leaves and inflorescences. Furthermore, RNAi knock-down transgenic plants exhibited additional unique phenotypes, including concave and heart-shape cotyledons, triple cotyledons, irregular and clustered guard cells, and defects in phyllotaxy, all of which are typical for defective cytokinin signaling. We next examined the mRNA level of cytokinin signaling compo-nents, including type-A ARRs, type-B ARRs, and CRFs. The expression of type-A ARRs, encoding negative regulators of cytokinin signaling, was markedly reduced in 35S:RNAi-RPN12a transgenic plants relative to that in wild type plants, while type-B ARRs and CRFs were unaffected. Our results also indicate that in vivo stability of the ARR5 protein, a negative regulator of cytokinin signaling, is mediated by the 26S proteasome complex. These results suggest that RPN12a participates in feedback inhibitory mechanism of cytokinin signaling through modulation of the abundance of ARR5 protein in Arabidopsis.

Keywords: 26S proteasome complex, Arabidopsis, cytokinin signaling, RNAi suppression, RPN12a

Mol. Cells
Feb 28, 2023 Vol.46 No.2, pp. 69~129
COVER PICTURE
The bulk tissue is a heterogeneous mixture of various cell types, which is depicted as a skein of intertwined threads with diverse colors each of which represents a unique cell type. Single-cell omics analysis untangles efficiently the skein according to the color by providing information of molecules at individual cells and interpretation of such information based on different cell types. The molecules that can be profiled at the individual cell by single-cell omics analysis includes DNA (bottom middle), RNA (bottom right), and protein (bottom left). This special issue reviews single-cell technologies and computational methods that have been developed for the single-cell omics analysis and how they have been applied to improve our understanding of the underlying mechanisms of biological and pathological phenomena at the single-cell level.

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