Much of what we know about eukaryotic transcription stems from animals and yeast; however, plants evolved separately for over a billion years, leaving ample time for divergence in transcriptional regulation. Here we set out to elucidate fundamental properties of cis-regulatory sequences in plants. Using massively parallel reporter assays across four plant species, we demonstrate the central role of sequences downstream of the transcription start site (TSS) in transcriptional regulation. Unlike animal enhancers that are position independent, plant regulatory elements depend on their position, as altering their location relative to the TSS significantly affects transcription. We highlight the importance of the region downstream of the TSS in regulating transcription by identifying a DNA motif that is conserved across vascular plants and is sufficient to enhance gene expression in a dose-dependent manner. The identification of a large number of position-dependent enhancers points to fundamental differences in gene regulation between plants and animals.

我们对真核转录的了解大部分来自动物和酵母。然而，植物分别进化了十亿多年，为转录调控的分化留下了充足的时间。在这里，我们着手阐明植物中顺式调控序列的基本特性。通过对四种植物进行大规模平行报告分析，我们证明了转录起始位点（TSS）下游序列在转录调控中的核心作用。与位置无关的动物增强子不同，植物调控元件依赖于它们的位置，因为改变它们相对于 TSS 的位置会显着影响转录。我们通过鉴定在维管束植物中保守且足以以剂量依赖性方式增强基因表达的DNA基序，强调了TSS下游区域在调节转录中的重要性。大量位置依赖性增强子的鉴定表明植物和动物之间基因调控的根本差异。