Wills C, Hom D
Department of Biology, University of California, San Diego, La Jolla 92093.
Genetics. 1988 Aug;119(4):791-5. doi: 10.1093/genetics/119.4.791.
Selection for resistance to allyl alcohol in respiration-incompetent Saccharomyces cerevisiae produces a high proportion of mutants that can be localized within the ADH2 structural gene and that still, because of the type of selection employed, retain enzyme activity. We show here that a similar type of selection produces a similarly high proportion of mutants resistant to the competitive inhibitor pyrazole. The first four mutants examined, picked at random from a collection of spontaneous pyrazole-resistant mutants, show altered--usually increased--KM values for ethanol and NAD+, and markedly increased K1 values for pyrazole, compared with the wild type. When these kinetic measures and their electrophoretic mobilities were compared, all the mutants could be clearly distinguished from each other as well as from wild type. Genetic analysis shows these mutants to be close to and probably resident in the structural gene. For a variety of reasons, these mutants are even more favorable subjects for population genetic analysis and the dissection of molecular microevolution than are allyl alcohol-resistant mutants.
在呼吸缺陷型酿酒酵母中筛选对烯丙醇的抗性会产生高比例的突变体，这些突变体可定位在ADH2结构基因内，并且由于所采用的筛选类型，仍保留酶活性。我们在此表明，类似类型的筛选会产生类似高比例的对竞争性抑制剂吡唑有抗性的突变体。从自发的吡唑抗性突变体集合中随机挑选的前四个检测的突变体，与野生型相比，显示出乙醇和NAD⁺的KM值发生改变——通常增加——以及吡唑的K1值显著增加。当比较这些动力学参数及其电泳迁移率时，所有突变体彼此之间以及与野生型都能明显区分开来。遗传分析表明这些突变体与结构基因接近且可能位于该结构基因中。由于多种原因，这些突变体比抗烯丙醇突变体更适合进行群体遗传分析和分子微进化剖析。
