Open AccessETHYLENE-INSENSITIVE5 encodes a 5′→3′ exoribonuclease required for regulation of the EIN3-targeting F-box proteins EBF1/2
Author(s) -
Gabriela Olmedo,
Haiyang Guo,
Brian D. Gregory,
Saeid Nourizadeh,
Laura Aguilar-Hein,
Hongjiang Li,
Fengying An,
Plinio Guzmán,
Joseph R. Ecker
Publication year - 2006
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0605528103
Subject(s) - ethylene , exoribonuclease , transcription factor , arabidopsis , microbiology and biotechnology , biology , gene expression , chemistry , regulation of gene expression , mutant , biochemistry , gene , rna , rnase p , catalysis
Ethylene is a gaseous plant growth regulator that controls a multitude of developmental and stress responses. Recently, the levels ofArabidopsis EIN3 protein, a key transcription factor mediating ethylene-regulated gene expression, have been demonstrated to increase in response to the presence of ethylene gas. Furthermore, in the absence of ethylene, EIN3 is quickly degraded through a ubiquitin/proteasome pathway mediated by two F-box proteins, EBF1 and EBF2. Here we report the identification ofETHYLENE-INSENSITIVE5 as the 5′→3′ exoribonucleaseXRN4 . Specifically, we demonstrate that EIN5 is a component of the ethylene signal transduction cascade acting downstream of CTR1 that is required for ethylene-mediated gene expression changes. Furthermore, we find that the ethylene insensitivity ofein5 mutant plants is a consequence of the over-accumulation ofEBF1 andEBF2 mRNAs resulting in the under-accumulation of EIN3 even in the presence of ethylene gas. Together, our results suggest that the role of EIN5 in ethylene perception is to antagonize the negative feedback regulation on EIN3 by promotingEBF1 andEBF2 mRNA decay, which consequently allows the accumulation of EIN3 protein to trigger the ethylene response.