title: Interaction between BZR1 and PIF4 integrates brassinosteroid and environmental responses.
abstract: Plant growth is coordinately regulated by environmental and hormonal signals. Brassinosteroid (BR) plays essential roles in growth regulation by light and temperature, but the interactions between BR and these environmental signals remain poorly understood at the molecular level. Here, we show that direct interaction between the dark- and heat-activated transcription factor phytochrome-interacting factor 4 (PIF4) and the BR-activated transcription factor BZR1 integrates the hormonal and environmental signals. BZR1 and PIF4 interact with each other in vitro and in vivo, bind to nearly 2,000 common target genes, and synergistically regulate many of these target genes, including the PRE family helix-loop-helix factors required for promoting cell elongation. Genetic analysis indicates that BZR1 and PIFs are interdependent in promoting cell elongation in response to BR, darkness or heat. These results show that the BZR1-PIF4 interaction controls a core transcription network, enabling plant growth co-regulation by the steroid and environmental signals.
authors: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
authors: Eunkyoo
authors: E
authors: Oh
authors: Jia-Ying
authors: JY
authors: Zhu
authors: Zhi-Yong
authors: ZY
authors: Wang
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D060406:Brassinosteroids / Q000378:metabolism*; D049108:Cell Enlargement; D004268:DNA-Binding Proteins; D018506:Gene Expression Regulation, Plant; D059647:Gene-Environment Interaction; D018546:Hypocotyl / Q000166:cytology / Q000528:radiation effects; D008027:Light; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D063245:Plant Development; D010944:Plants / Q000528:radiation effects; D011485:Protein Binding; D013696:Temperature
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D060406:Brassinosteroids; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C454444:BZR1 protein, Arabidopsis; C459466:PIF4 protein, Arabidopsis