A dose-dependent bimodal switch by homologous Aux/IAA transcriptional repressors  

作　　者：Hyung-Taeg Cho Minsu Lee Hee-Seung Choi Kwang-Ho Maeng Kyeonghoon Lee Ha-Yeon Lee Anindya Ganguly Hoonyoung Park Chang-Hoi Ho 

机构地区：[1]Department of Biological Sciences,Seoul National University,Seoul,Korea [2]School of Earth and Environmental Sciences,Seoul National University,Seoul,Korea [3]Department of Climate and Energy Systems Engineering,Ewha Womans University,Seoul,Korea

出　　处：《Molecular Plant》2024年第9期1407-1422,共16页分子植物（英文版）

基　　金：supported by a grant from the National Research Foundation(NRF-2022R1A2C1007862).

摘　　要：Combinatorial interactions between different regulators diversify and enrich the chance of transcriptional regulation in eukaryotic cells.However,a dose-dependent functional switch of homologous transcriptional repressors has rarely been reported.Here,we show that SHY2,an auxin/indole-3-acetic acid(Aux/IAA)repressor,exhibits a dose-dependent bimodal role in auxin-sensitive root-hair growth and gene transcrip-tion in Arabidopsis,whereas other Aux/lAA homologs consistently repress the auxin responses.The co-repressor(TOPLESS[TPL])-binding affinity of a bimodal Aux/IAA was lower than that of a consistently re-pressing Aux/IAA.The switch of a single amino acid residue in the TPL-binding motif between the bimodal form and the consistently repressing form switched their TPL-binding affinity and transcriptional and bio-logical roles in auxin responses.Based on these data,we propose a model whereby competition between homologous repressors with different co-repressor-binding affinities could generate a bimodal output at thetranscriptional anddevelopmental levels.

关 键 词：AUXIN AUX/IAA dose-dependent regulation root hair transcription TOPLESS(TPL) 

分 类 号：Q94[生物学—植物学]