Hutchison C A, Nordeen S K, Vogt K, Edgell M H
Proc Natl Acad Sci U S A. 1986 Feb;83(3):710-4. doi: 10.1073/pnas.83.3.710.
The glucocorticoid response element (GRE) of mouse mammary tumor virus (MMTV) was chemically synthesized as two complementary DNA strands bearing cohesive termini. During automated synthesis, random mutations were introduced into the DNA by "doping" each of the four nucleoside phosphoramidites (A, G, C, and T) with a low level of the other three. These preparations were annealed and cloned into an M13 phage vector to produce a library of GRE mutants. Mutations within the synthesized region were identified by sequencing phage isolates at random. All of the chemically distinct classes of transition and transversion mutations have been observed. Statistical considerations indicate that the library contains all of the possible 90 point substitution mutations within a 30-nucleotide mutagenic target. So far 88 of these substitutions have been isolated, 74 as single mutants. At least two of the three possible single mutants at each of the 30 positions have been identified.
小鼠乳腺肿瘤病毒（MMTV）的糖皮质激素反应元件（GRE）通过化学合成形成两条带有粘性末端的互补DNA链。在自动合成过程中，通过用低水平的其他三种核苷亚磷酰胺（A、G、C和T）“掺杂”四种核苷亚磷酰胺中的每一种，将随机突变引入DNA。将这些制剂退火并克隆到M13噬菌体载体中，以产生GRE突变体文库。通过随机测序噬菌体分离株来鉴定合成区域内的突变。已经观察到所有化学上不同类别的转换和颠换突变。统计分析表明，该文库包含30个核苷酸诱变靶点内所有可能的90个点替换突变。到目前为止，已分离出其中88个替换突变，74个为单突变体。在30个位置中的每一个位置上，三种可能的单突变体中至少有两种已被鉴定出来。
