Schaffitzel Christiane, Postberg Jan, Paeschke Katrin, Lipps Hans J
Institute for Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland.
Methods Mol Biol. 2010;608:159-81. doi: 10.1007/978-1-59745-363-9_11.
Guanine-rich sequences have been shown to readily form parallel or antiparallel G-quadruplex DNA structures in vitro. All telomeric repeat sequences contain stretches of guanine residues that can form quadruplex structures. In order to demonstrate the occurrence of the quadruplex structure in vivo, we generated by ribosome display, scFv antibodies specific for quadruplex DNA structures formed by the telomeric sequence of the ciliate Stylonychia. The macronucleus of this hypotrichous ciliate contains 10(8) telomere-capped nanochromosomes and was stained with the antibody recognizing the antiparallel G-quadruplex DNA in indirect immuno-fluorescence assays. This antibody was also used as a specific probe to study the interaction of the telomere end-binding proteins with the G-quadruplex during different stages of the cell cycle.
富含鸟嘌呤的序列已被证明在体外易于形成平行或反平行的G-四链体DNA结构。所有端粒重复序列都包含可形成四链体结构的鸟嘌呤残基片段。为了证明四链体结构在体内的存在，我们通过核糖体展示技术生成了对纤毛虫类Stylonychia的端粒序列形成的四链体DNA结构具有特异性的单链抗体片段（scFv）抗体。这种下毛目纤毛虫的大核包含10^8个端粒帽纳米染色体，并在间接免疫荧光分析中用识别反平行G-四链体DNA的抗体进行染色。该抗体还被用作特异性探针来研究端粒末端结合蛋白在细胞周期不同阶段与G-四链体的相互作用。
