655 / 2019-04-29 22:45:35

Ubiquitination machineries acting at the interface between light signaling and epigenome dynamics in Arabidopsis

Light signaling,Epigenetics,Ubiquitin,Arabidopsis,Photomorphogenesis,Histone modification,DET1,CUL4 E3 ligases,DUBm

全体主题 > Signal Transduction

Photomorphogenesis is a developmental switch that initiates upon light perception and involves a huge transcriptional reprograming. It requires a fine control of the activity of specific transcription activators and the modification of chromatin marks that facilitates Polymerase II progression, as well as intense protein turnover via the ubiquitin-proteasome system. DE-ETIOLATED1 (DET1) is an atypical DDB1-CULLIN4 Associated Factor (DCAF) that, together with DDB1, COP10 and DDA1, constitutes a substrate adaptor module of CUL4 E3 ubiquitin ligases. These complexes are well conserved among species, controlling the stability of cell proliferation factors in animals or circadian and photomorphogenesis regulators in plants. However, the exact mechanism by which DET1 affects the stability of these regulators and controls transcription has remained largely unknown. Recently, we have shown that DET1 controls monoubiquitinated H2B (H2Bub) abundance and distribution throughout the Arabidopsis genome. For this, the DET1-associated protein DDA1, directly interacts with SGF11, a member of an Arabidopsis H2Bub deubiquitination module (DUBm), promoting its destabilization. By controlling the light-dependent degradation of DUBm, DET1-complexes control H2Bub homeostasis and transcriptional output. Thus, our findings support a model in which H2B ubiquitination and deubiquitination dynamics impact photomorphogenesis by regulating transcription through progression of Polymerase II.