Oh Doo-Byoung, Kim Yang-Gyun, Rich Alexander
Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Proc Natl Acad Sci U S A. 2002 Dec 24;99(26):16666-71. doi: 10.1073/pnas.262672699. Epub 2002 Dec 16.
The role of Z-DNA-binding proteins in vivo is explored in yeast. A conformation-specific yeast one-hybrid system is made in which formation of Z-DNA is studied near a minimal promoter site where it can be stabilized by negative supercoiling in addition to protein binding. Experiments were carried out with a Z-DNA-binding protein domain from the editing enzyme, double-stranded RNA adenosine deaminase 1. In the one-hybrid system, the reporter gene is activated when a Z-DNA-specific binding domain is fused with an activation domain and expressed in vivo. Significantly, it was found that even in the absence of the activation domain there is substantial transcription of the reporter gene if the Z-DNA-binding protein is expressed in the cell. This result suggests that Z-DNA formation in the promoter region induced or stabilized by a Z-DNA-binding protein can act as a cis-element in gene regulation. Related results have been found recently when the human chromatin-remodeling system converts a segment of DNA in the promoter region of the human colony-stimulating factor 1 gene into the left-handed Z-conformation.
在酵母中探索了Z-DNA结合蛋白在体内的作用。构建了一种构象特异性酵母单杂交系统，在该系统中，在最小启动子位点附近研究Z-DNA的形成，除了蛋白质结合外，它还可以通过负超螺旋来稳定。使用来自编辑酶双链RNA腺苷脱氨酶1的Z-DNA结合蛋白结构域进行了实验。在单杂交系统中，当Z-DNA特异性结合结构域与激活结构域融合并在体内表达时，报告基因被激活。值得注意的是，发现即使在没有激活结构域的情况下，如果Z-DNA结合蛋白在细胞中表达，报告基因也会有大量转录。该结果表明，由Z-DNA结合蛋白诱导或稳定的启动子区域中的Z-DNA形成可以作为基因调控中的顺式元件。最近，当人类染色质重塑系统将人类集落刺激因子1基因启动子区域的一段DNA转化为左手Z构象时，也发现了相关结果。
