细胞DNA和合成DNA中独特的聚（dA）·聚（dT）B'构象
Unique poly(dA).poly(dT) B'-conformation in cellular and synthetic DNAs.
作者信息
Diekmann S, Zarling D A
出版信息
Nucleic Acids Res. 1987 Aug 11;15(15):6063-74. doi: 10.1093/nar/15.15.6063.
Poly(dA).poly(dT), but not B-form DNA, is specifically recognized by experimentally induced anti-kinetoplast or anti-poly(dA).poly(dT) immunoglobulins. Antibody binding is completely competed by poly(dA).poly(dT) and poly(dA).poly(dU) but not by other single- or double-stranded DNA sequences in a right-handed B-form. Antibody interaction with poly(dA).poly(dT) depends on immunoglobulin concentration, incubation time and temperature, and is sensitive to elevated ionic strengths. Similar conformations, for example, (dA)4-6 X (dT)4-6, in the kinetoplast DNA of the parasite Leishmania tarentolae are also immunogenic and induce specific anti-poly(dA).poly(dT) antibodies. These antibody probes specifically recognize nuclear and kinetoplast DNA in fixed flagellated kinetoplastid cells as evidenced by immunofluorescence microscopy. Anti-poly(dA).poly(dT) immunofluorescence is DNase-sensitive and competed by poly(dA).poly(dT), but not other classical double-stranded B-DNAs. Thus, these unique cellular B'-DNA helices are immunogenic and structurally similar to synthetic poly(dA).poly(dT) helices in solution.
聚（dA）·聚（dT），而非B型DNA，能被实验诱导产生的抗动质体或抗聚（dA）·聚（dT）免疫球蛋白特异性识别。抗体结合能被聚（dA）·聚（dT）和聚（dA）·聚（dU）完全竞争，但不能被右手B型的其他单链或双链DNA序列竞争。抗体与聚（dA）·聚（dT）的相互作用取决于免疫球蛋白浓度、孵育时间和温度，并且对离子强度升高敏感。寄生虫塔氏利什曼原虫动质体DNA中类似的构象，如（dA）4 - 6×（dT）4 - 6，也具有免疫原性，并能诱导产生特异性抗聚（dA）·聚（dT）抗体。通过免疫荧光显微镜观察证明，这些抗体探针能特异性识别固定的有鞭毛动基体目细胞中的核DNA和动质体DNA。抗聚（dA）·聚（dT）免疫荧光对DNA酶敏感，并能被聚（dA）·聚（dT）竞争，但不能被其他经典的双链B - DNA竞争。因此，这些独特的细胞B' - DNA螺旋具有免疫原性，并且在结构上与溶液中的合成聚（dA）·聚（dT）螺旋相似。
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