Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia.
Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia.
Biochim Biophys Acta Gene Regul Mech. 2020 Jan;1863(1):194446. doi: 10.1016/j.bbagrm.2019.194446. Epub 2019 Nov 6.
Recently, the concept has arisen that a special class of architectural proteins exists, which are responsible not only for global chromosome architecture but also for the local regulation of enhancer-promoter interactions. Here, we describe a new architectural protein, with a total size of only 375 aa, which contains an N-terminal zinc finger-associated domain (ZAD) and a cluster of five zinc finger C2H2 domains at the C-terminus. This new protein, named ZAD and Architectural Function 1 protein (ZAF1 protein), is weakly and ubiquitously expressed, with the highest expression levels observed in oocytes and embryos. The cluster of C2H2 domains recognizes a specific 15-bp consensus site, located predominantly in promoters, near transcription start sites. The expression of ZAF1 by a tissue-specific promoter led to the complete blocking of the eye enhancer when clusters of ZAF1 binding sites flanked the eye enhancer in transgenic lines, suggesting that the loop formed by the ZAF1 protein leads to insulation. The ZAF1 protein also supported long-range interactions between the yeast GAL4 activator and the white promoter in transgenic Drosophila lines. A mutant protein lacking the ZAD failed to block the eye enhancer or to support distance interactions in transgenic lines. Taken together, these results suggest that ZAF1 is a minimal architectural protein that can be used to create a convenient model for studying the mechanisms of distance interactions.
最近，人们提出了一个概念，即存在一类特殊的结构蛋白，它们不仅负责全局染色体结构，还负责局部调节增强子-启动子相互作用。在这里，我们描述了一种新的结构蛋白，其总大小仅为 375 个氨基酸，包含一个 N 端锌指相关结构域（ZAD）和 C 端的五个锌指 C2H2 结构域簇。这种新的蛋白质，命名为 ZAD 和结构功能 1 蛋白（ZAF1 蛋白），表达较弱且广泛，在卵母细胞和胚胎中表达水平最高。C2H2 结构域簇识别一个特定的 15 个碱基对的保守序列，主要位于启动子附近，靠近转录起始位点。组织特异性启动子表达 ZAF1 蛋白时，当 ZAF1 结合位点簇环绕转基因品系中的眼增强子时，会完全阻断眼增强子的表达，表明 ZAF1 蛋白形成的环导致了隔离。ZAF1 蛋白还支持酵母 GAL4 激活子和转基因果蝇品系中白色启动子之间的长距离相互作用。缺乏 ZAD 的突变体蛋白无法阻断眼增强子或支持转基因品系中的远距离相互作用。总之，这些结果表明 ZAF1 是一种最小的结构蛋白，可以用于构建研究远距离相互作用机制的方便模型。
