DET1-mediated COP1 regulation avoids HY5 activity over second-site gene targets to tune plant photomorphogenesis

• 作者: Esther Ca?ibano Clara Bourbousse Marta García-León Borja Garnelo Gómez Léa Wolff Camila García-Baudino Rosa Lozano-Durán Fredy Barneche Vicente Rubio Sandra Fonseca
• 来源期刊: 分子植物（英文版）
• 年，卷（期）: 2021,（6）
• 所属期刊栏目: Research Articles
• 页码范围: 963-982
• 页数: 20页
• 语种: 英文

摘要

DE-ETIOLATED1(DET1)and CONSTITUTIVE PHOTOMORPHOGENESIS1(COP1)are two essential repres-sors of Arabidopsis photomorphogenesis.These proteins can associate with CULLIN4 to form independent CRL4-based E3 ubiquitin ligases that mediate the degradation of several photomorphogenic transcription factors,including ELONGATED HYPOCOTYL 5(HY5),thereby controlling multiple gene-regulatory net-works.Despite extensive biochemical and genetic analyses of their multi-subunit complexes,the func-tional links between DET1 and COP1 have long remained elusive.Here,we report that DET1 associates with COP1 in vivo,enhances COP1-HY5 interaction,and promotes COP1 destabilization in a process that dampens HY5 protein abundance.By regulating its accumulation,DET1 avoids HY5 association with hundreds of second-site genomic loci,which are also frequently targeted by the skotomorphogenic tran-scription factor PHYTOCHROME-INTERACTING FACTOR 3.Accordingly,ectopic HY5 chromatin enrich-ment favors local gene repression and can trigger fusca-like phenotypes.This study therefore shows that DET1-mediated regulation of COP1 stability tunes down the HY5 cistrome,avoiding hyper-photomorphogenic responses that might compromise plant viability.