Plant Science Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, UK.
Mol Plant. 2008 Jan;1(1):118-28. doi: 10.1093/mp/ssm012. Epub 2007 Oct 31.
Arabidopsis UV RESISTANCE LOCUS8 (UVR8) is a UV-B-specific signaling component that regulates expression of a range of genes concerned with UV protection. Here, we investigate the interaction of UVR8 with chromatin. Using antibodies specific to UVR8 in chromatin immunoprecipitation (ChIP) assays with wild-type plants, we show that native UVR8 binds to chromatin in vivo. Similar experiments using an anti-GFP antibody with plants expressing a GFP-UVR8 fusion show that UVR8 associates with a relatively small region of chromatin containing the HY5 gene. UVR8 interacts with chromatin containing the promoter regions of other genes, but not with all the genes it regulates. UV-B is not required for the interaction of UVR8 with chromatin because association with several gene loci is observed in the absence of UV-B. Pull-down assays demonstrate that UVR8 associates with histones in vivo and competition experiments indicate that the interaction is preferentially with histone H2B. ChIP experiments using antibodies that recognize specific histone modifications indicate that the UV-B-stimulated transcription of some genes may be correlated with histone modification. In particular, the ELIP1 promoter showed a significant enrichment of diacetyl histone H3 (K9/K14) following UV-B exposure. These findings increase understanding of the interaction of the key UV-B-specific regulator UVR8 with chromatin.
拟南芥紫外线抵抗基因 8（UVR8）是一种 UV-B 特异性信号转导元件，它调节与 UV 保护相关的一系列基因的表达。在这里，我们研究了 UVR8 与染色质的相互作用。在野生型植物的染色质免疫沉淀（ChIP）实验中使用针对 UVR8 的特异性抗体，我们表明天然 UVR8 在体内与染色质结合。使用表达 GFP-UVR8 融合蛋白的植物中的抗 GFP 抗体进行类似的实验表明，UVR8 与包含 HY5 基因的相对较小的染色质区域相关联。UVR8 与包含其他基因启动子区域的染色质相互作用，但并非与它调节的所有基因都相互作用。UV-B 不是 UVR8 与染色质相互作用所必需的，因为在没有 UV-B 的情况下，几个基因座的关联就可以观察到。下拉实验表明 UVR8 与体内的组蛋白相互作用，竞争实验表明这种相互作用优先与组蛋白 H2B 发生。使用识别特定组蛋白修饰的抗体的 ChIP 实验表明，一些基因的 UV-B 刺激转录可能与组蛋白修饰相关。特别是，ELIP1 启动子在暴露于 UV-B 后显示出二乙酰化组蛋白 H3（K9/K14）的显著富集。这些发现增加了对关键的 UV-B 特异性调节剂 UVR8 与染色质相互作用的理解。
