A dose-dependent bimodal switch by homologous Aux/IAA transcriptional repressors.
Mol Plant
; 17(9): 1407-1422, 2024 Sep 02.
Article
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| MEDLINE
| ID: mdl-39095993
ABSTRACT
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 transcription in Arabidopsis, whereas other Aux/IAA 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 repressing 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 biological 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 the transcriptional and developmental levels.
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1
Base de datos:
MEDLINE
Asunto principal:
Proteínas Represoras
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Arabidopsis
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Regulación de la Expresión Génica de las Plantas
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Proteínas de Arabidopsis
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Ácidos Indolacéticos
Idioma:
En
Revista:
Mol Plant
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Molecular plant (Online)
Asunto de la revista:
BIOLOGIA MOLECULAR
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BOTANICA
Año:
2024
Tipo del documento:
Article