Hyttinen J M, Myöhänen S, Jansson K
Division of Environmental Health, National Public Health Institute, Kuopio, Finland.
Carcinogenesis. 1996 May;17(5):1179-81. doi: 10.1093/carcin/17.5.1179.
The kinds of mutations induced by 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) in the protein coding region of the hprt gene of Chinese hamster ovary (CHO) cells were determined by direct sequencing of polymerase chain reaction (PCR)-amplified cDNA. Primary mutations were found in 15 of 19 of the mutants: 11 were G:C-->T:A transversions, two were A:T-->T:A transversions and two were deletions of single G:C base pairs (-1 frameshifts). The remaining four mutants had large alterations in the cDNA that were explained by mRNA splicing errors. A group of control mutants had more diverse hprt cDNA alterations than MX-induced mutants. Transversions yielding an A:T base pair were the predominant type of MX-induced mutations, in agreement with previous findings in bacteria. This specificity may be explained by the 'A rule', that DNA polymerases preferentially insert adenine nucleotides opposite non-instructional lesions.
通过对聚合酶链反应（PCR）扩增的互补DNA（cDNA）进行直接测序，确定了3-氯-4-（二氯甲基）-5-羟基-2（5H）-呋喃酮（MX）在中国仓鼠卵巢（CHO）细胞次黄嘌呤磷酸核糖转移酶（hprt）基因编码区诱导的突变类型。在19个突变体中的15个中发现了初级突变：11个是G:C→T:A颠换，2个是A:T→T:A颠换，2个是单个G:C碱基对的缺失（-1移码）。其余4个突变体的cDNA有较大改变，这可由mRNA剪接错误来解释。一组对照突变体的hprt cDNA改变比MX诱导的突变体更多样化。产生A:T碱基对的颠换是MX诱导突变的主要类型，这与先前在细菌中的发现一致。这种特异性可能由“A规则”来解释，即DNA聚合酶优先在非指令性损伤的对面插入腺嘌呤核苷酸。
