PDF(Pubmed)
Abstract：
The switch defective/sucrose non-fermentable (SWI/SNF) multisubunit complex plays an important role in the regulation of gene expression by remodeling chromatin structure. Three SWI/SNF complexes have been identified in Arabidopsis including BAS, SAS, and MAS. Many subunits of these complexes are involved in controlling plant development and stress response. However, the function of these complexes has hardly been studied in other plant species. In this study, we identified the subunits of the SWI/SNF complex in sorghum and analyzed their evolutionary relationships in six grass species. The grass species conserved all the subunits as in Arabidopsis, but gene duplication occurred diversely in different species. Expression pattern analysis in sorghum (Sorghum bicolor) showed that most of the subunit-encoding genes were expressed constitutively, although the expression level was different. Transactivation assays revealed that SbAN3, SbGIF3, and SbSWI3B possessed transactivation activity, which suggests that they may interact with the pre-initiation complex (PIC) to activate transcription. We chose 12 subunits in sorghum to investigate their interaction relationship by yeast two-hybrid assay. We found that these subunits displayed distinct interaction patterns compared to their homologs in Arabidopsis and rice. This suggests that different SWI/SNF complexes may be formed in sorghum to perform chromatin remodeling functions. Through the integrated analysis of MNase-seq and RNA-seq data, we uncovered a positive relationship between gene expression levels and nucleosome phasing. Furthermore, we found differential global nucleosome enrichments between leaves and roots, as well as in response to PEG treatment, suggesting that dynamics of nucleosome occupancy, which is probably mediated by the SWI/SNF complex, may play important roles in sorghum development and stress response.
摘要：
开关缺陷/蔗糖不可发酵（SWI/SNF）多亚基复合物通过重塑染色质结构在调节基因表达中起重要作用。在拟南芥中已鉴定出三种SWI/SNF复合物，包括BAS，SAS,和MAS。这些复合物的许多亚基参与控制植物发育和胁迫反应。然而,这些复合物的功能在其他植物物种中几乎没有研究过。在这项研究中,我们确定了高粱中SWI/SNF复合物的亚基，并分析了它们在六种草种中的进化关系。草种保存了拟南芥中的所有亚基，但是基因重复在不同的物种中发生。高粱（Sorghumbicolor）的表达模式分析表明，大多数亚基编码基因是组成型表达的，尽管表达水平不同。反式激活实验显示SbAN3、SbGIF3和SbSWI3B具有反式激活活性,这表明它们可能与预起始复合物（PIC）相互作用以激活转录。我们选择了高粱中的12个亚基，通过酵母双杂交试验研究了它们的相互作用关系。我们发现，与拟南芥和水稻的同源物相比，这些亚基显示出不同的相互作用模式。这表明高粱中可能形成不同的SWI/SNF复合物以执行染色质重塑功能。通过对MNase-seq和RNA-seq数据的整合分析，我们发现基因表达水平与核小体定相之间存在正相关关系。此外，我们发现叶和根之间存在差异的整体核小体富集，以及对PEG治疗的反应，表明核小体占据的动力学，这可能是由SWI/SNF复合物介导的，可能在高粱发育和应激反应中起重要作用。
