Phear G, Armstrong W, Meuth M
Imperial Cancer Research Fund, Clare Hall Laboratories, Hertfordshire, U.K.
J Mol Biol. 1989 Oct 20;209(4):577-82. doi: 10.1016/0022-2836(89)90595-0.
Mutations occurring spontaneously at the hamster aprt locus were examined at the base-pair level by amplifying target sequences using the polymerase chain reaction and then directly sequencing the double-stranded products. In a collection of 89 sequenced genes, all types of mutations were found, with transitions (mostly G.C to A.T) constituting the largest class (35%), transversions accounting for 27%, and small deletions/duplications for 25%. Simple base substitutions were distributed throughout the aprt structural gene with few sites having recurring mutations and G.C base-pairs being the predominant substitution target. Small deletions, on the other hand, were not distributed so evenly, being concentrated in a region of aprt rich in short direct and inverted repeat sequences. The base substitutions were predominantly missense, while about 10% produced nonsense codons. Splice junctions, and start and stop codons were also significant targets for mutation. No alterations were detected in three aprt-deficient strains after sequencing all exons and substantial upstream and downstream regions.
通过聚合酶链反应扩增靶序列，然后对双链产物进行直接测序，在碱基对水平上研究仓鼠aprt基因座自发发生的突变。在一组89个测序基因中，发现了所有类型的突变，转换（主要是G.C到A.T）构成最大类别（35%），颠换占27%，小缺失/重复占25%。简单碱基替换分布在整个aprt结构基因中，很少有位点发生重复突变，G.C碱基对是主要的替换靶点。另一方面，小缺失分布不那么均匀，集中在富含短直接和反向重复序列的aprt区域。碱基替换主要是错义突变，约10%产生无义密码子。剪接位点以及起始和终止密码子也是重要的突变靶点。在对所有外显子以及大量上游和下游区域进行测序后，在三个aprt缺陷菌株中未检测到改变。
