Project description:Plant photomorphogenesis is a light-induced developmental switch combining rapid enrichment in RNA Polymerase II activity and massive gene expression reprogramming. Yet, all former transcriptome analyses of this transition detected no average tendency toward gene upregulation. By applying a spike-in RNA-seq approach, we solved this conundrum and reconciled transcriptome dynamics with epigenomic and cytogenetic data. This further unveiled that Arabidopsis cotyledon photomorphogenesis involves a ~2-fold expansion of the transcriptome, a trend that we reproducibly observed in datasets from independent laboratories upon normalization using a set of stable genes defined ad hoc. This new standpoint enabled us to reinterpret light-mediated gene regulatory paths and unveil a quasi-exclusive positive effect of light-induced transcription factors on target genes. Collectively, this study reveals how environmentally controlled variations of the transcriptional regime can functionally impact plant genome expression. It further establishes a framework for investigating the mechanisms of global genome regulation in these organisms.
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:Plant photomorphogenesis is a light-induced developmental switch combining rapid enrichment in RNA Polymerase II activity and massive gene expression reprogramming. Yet, all former transcriptome analyses of this transition detected no average tendency toward gene upregulation. By applying a spike-in RNA-seq approach, we solved this conundrum and reconciled transcriptome dynamics with epigenomic and cytogenetic data. This further unveiled that Arabidopsis cotyledon photomorphogenesis involves a ~2-fold expansion of the transcriptome, a trend that we reproducibly observed in datasets from independent laboratories upon normalization using a set of stable genes defined ad hoc. This new standpoint enabled us to reinterpret light-mediated gene regulatory paths and unveil a quasi-exclusive positive effect of light-induced transcription factors on target genes. Collectively, this study reveals how environmentally controlled variations of the transcriptional regime can functionally impact plant genome expression. It further establishes a framework for investigating the mechanisms of global genome regulation in these organisms.