RNA quality control (RQC) and post-transcriptional gene silencing (PTGS) target and degrade aberrant endogenous RNAs and foreign RNAs, contributing to homeostasis of cellular RNAs. In plants, RQC and PTGS compete for foreign and selected endogenous RNAs; however, little is known about the mechanism interconnecting the two pathways. Using a reporter system designed for monitoring PTGS, we revealed that the 26S proteasome subunit RPT2a enhances transgene PTGS by promoting the accumulation of transgene-derived short interfering RNAs without affecting their biogenesis. RPT2a physically associated with a subset of RQC components and downregulated the protein level. Overexpression of the RQC components interfered with transgene silencing, and impairment of the RQC machinery reinforced transgene PTGS attenuated by rpt2a. Overall, we demonstrate that the 26S proteasome subunit RPT2a promotes PTGS by repressing the RQC machinery to control foreign RNAs.
Bibliographical noteFunding Information:
We thank Y. Watanabe for the pDCP2-DCP2-GFP transgenic line, H. Lange for the RRP41-GFP and RRP41-MYC transgenic plants, H. Vaucheret for the L1 line, S. Park for the JAP3 transgenic plants, C. You and J. H. Park for the technical advice. This work was supported by IBS-R013-G2 from the Institute for Basic Science and in part by a grant from National Research Foundation (2019R1A2C3007376) and start-up funds from DGIST to J.M.K., and in part by (IBS‐R013‐D1) from the Institute for Basic Science.
© 2019, The Author(s), under exclusive licence to Springer Nature Limited.
All Science Journal Classification (ASJC) codes
- Plant Science