Project description:Brassinosteroids (BRs) are important regulators for plant growth and development. BRs signal to control the activities of the BES1 and BZR1 family transcription factors. In order to further understand the mechanism by which BES1/BZR1 regulates downstream genes, we performed chromatin immunoprecipitation coupled with tiling arrays (ChIP-chip) to identify BES1 binding sites in the genome. By combining ChIP-chip data with gene expression microarray data, we are able to discover genes that are directly regulated by BES1 (i.e. BES1 target genes). Chromatin from bes1-D Arabidopsis seedlings are immunoprecipitated by anti-BES1 antibody with anti-GFP antibody as control.
Project description:Brassinosteroids (BRs) are important regulators for plant growth and development. BRs signal to control the activities of the BES1 and BZR1 family transcription factors. In order to further understand the mechanism by which BES1/BZR1 regulates downstream genes, we performed chromatin immunoprecipitation coupled with tiling arrays (ChIP-chip) to identify BES1 binding sites in the genome. By combining ChIP-chip data with gene expression microarray data, we are able to discover genes that are directly regulated by BES1 (i.e. BES1 target genes).
Project description:Auxin is a major plant hormone for both development and environmental adaptation. Auxin responses are context dependent and highly modulated by light, temperature, the circadian clock, brassinosteroid, and gibberellin, but the underlying mechanisms remain unclear. Here, we show that auxin signaling integrates with other signals through direct interactions of AUXIN RESPONSE FACTOR6 (ARF6) with PHYTOCHROME INTERACTING FACTOR4 (PIF4), the brassinosteroid-signaling transcription factor BZR1, and the gibberellin-signaling repressor RGA. ChIP-Seq and RNA-Seq experiments show that ARF6, PIF4, and BZR1 bind to largely overlapping targets in the genome and synergistically activate gene expression. In vitro and in vivo assays show that ARF6-promoter binding is enhanced by PIF4 and BZR1 but blocked by RGA. Furthermore, a tripartite HLH/bHLH module feedback regulates PIF activity and thus modulates auxin sensitivity according to additional developmental and environmental cues. Our results demonstrate a central growth-regulation transcriptional network that coordinates hormonal, environmental, and developmental control of cell elongation and plant growth. Genome-wide identification of ARF6 DNA-binding sites in etiolated Arabidopsis seedlings.