Mediator Subunit MED25 Couples Alternative Splicing of JAZ Genes with Fine-Tuning of Jasmonate Signaling.

Fangming Wu, Lei Deng, Qingzhe Zhai, Jiuhai Zhao, Qian Chen, Chuanyou Li

The Plant cell 2020 Feb

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JASMONATE ZIM-DOMAIN (JAZ) transcriptional repressors are key regulators of jasmonate (JA) signaling in plants. At the resting stage, the C-terminal Jas motifs of JAZ proteins bind the transcription factor MYC2 to repress JA signaling. Upon hormone elicitation, the Jas motif binds the hormone receptor CORONATINE INSENSITIVE1, which mediates proteasomal degradation of JAZs and thereby allowing the Mediator subunit MED25 to activate MYC2. Subsequently, plants desensitize JA signaling by feedback generation of dominant JAZ splice variants that repress MYC2. Here we report the mechanistic function of Arabidopsis (Arabidopsis thaliana) MED25 in regulating the alternative splicing of JAZ genes through recruiting the splicing factors PRE-mRNA-PROCESSING PROTEIN 39a (PRP39a) and PRP40a. We demonstrate that JA-induced generation of JAZ splice variants depends on MED25 and that MED25 recruits PRP39a and PRP40a to promote the full splicing of JAZ genes. Therefore, MED25 forms a module with PRP39a and PRP40a to prevent excessive desensitization of JA signaling mediated by JAZ splice variants. © 2020 American Society of Plant Biologists. All rights reserved.

Citation

Fangming Wu, Lei Deng, Qingzhe Zhai, Jiuhai Zhao, Qian Chen, Chuanyou Li. Mediator Subunit MED25 Couples Alternative Splicing of JAZ Genes with Fine-Tuning of Jasmonate Signaling. The Plant cell. 2020 Feb;32(2):429-448