具有改变的RNA聚合酶II的对α-鹅膏蕈碱有抗性的黑腹果蝇。

Alpha-amanitin-resistant D. melanogaster with an altered RNA polymerase II.

作者信息

Greenleaf A L, Borsett L M, Jiamachello P F, Coulter D E

出版信息

Cell. 1979 Nov;18(3):613-22. doi: 10.1016/0092-8674(79)90116-8.

Abstract

Following EMS mutagenesis we recovered a mutant of D. melanogaster that grows at concentrations of alpha-amanitin lethal to wild-type. To our knowledge this mutant represents the first example of an amanitin-resistant eucaryotic organism. The amanitin resistance of the mutant (AmaC4) is due to an alteration in its DNA-dependent RNA polymerase II, which is approximately 250 times less sensitive to inhibition by amanitin than the wild-type polymerase II whether tested in nuclei, in partially-fractionated extracts or as a highly purified enzyme. While the wild-type enzyme activity is inhibited 50% by 2.1 x 10(-8) M alpha-amanitin, inhibition of 50% of the AmaC4 RNA polymerase II activity requires a toxin concentration of 5.6 x 10(-6) M. The mutation responsible for the amanitin resistance of AmaC4 is on the X chromosome near the vermillion locus.

摘要

在进行EMS诱变后，我们获得了一种黑腹果蝇突变体，它能在对野生型致死的α-鹅膏蕈碱浓度下生长。据我们所知，这种突变体是抗鹅膏蕈碱真核生物的首个例子。该突变体（AmaC4）对鹅膏蕈碱的抗性源于其依赖DNA的RNA聚合酶II的改变，无论是在细胞核中、部分分级提取物中还是作为高度纯化的酶进行测试时，它对鹅膏蕈碱抑制作用的敏感性都比野生型聚合酶II低约250倍。野生型酶活性在2.1×10⁻⁸ M的α-鹅膏蕈碱作用下被抑制50%，而抑制AmaC4 RNA聚合酶II活性的50%则需要5.6×10⁻⁶ M的毒素浓度。导致AmaC4对鹅膏蕈碱产生抗性的突变位于X染色体上靠近朱红色基因座的位置。