Specific action of T4 endonuclease V on damaged DNA in xeroderma pigmentosum cells in vivo.
Specific action of T4 endonuclease V on damaged DNA in xeroderma pigmentosum cells in vivo.
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T4 核酸内切酶 V 对体内着色性干皮病细胞受损 DNA 的特异性作用。
DOI：
10.1073/pnas.74.7.2958
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发表时间：
1977
影响因子：
11.1
通讯作者：
Y. Okada
中科院分区：
文献类型：
--
作者：
K. Tanaka;H. Hayakawa;M. Sekiguchi;Y. Okada
用紫外线灭活的日本血凝病毒（仙台病毒）体内测定系统，研究了T4核酸内切酶V对着色性干皮病细胞中受损DNA的特异性作用。在着色性干皮病细胞的UV诱导的非程序性DNA合成水平和添加的T4核酸内切酶V活性的量之间观察到明显的剂量反应。T4酶在人体细胞中是不稳定的，其半衰期为3 hr. Fractions来自大肠杆菌感染T4 V1，一个突变体的核酸内切酶V基因缺陷的提取物，显示没有能力恢复UV诱导的非程序DNA合成的着色性干皮病细胞。然而，来自T4 D感染的E.大肠杆菌中具有核酸内切酶V活性。T4酶在着色性干皮病细胞中对UV光损伤的DNA有效，但在4-硝基喹啉1-氧化物损伤的细胞中无效。这些实验的结果表明，T4酶在体内对人细胞DNA具有特异性作用。用T4酶处理增加了UV照射后A组着色性干皮病细胞的存活。
The specific action of T4 endonuclease V on damaged DNA in xeroderma pigmentosum cells was examined using an in vivo assay system with hemagglutinating virus of Japan (Sendai virus) inactivated by UV light. A clear dose response was observed between the level of UV-induce unscheduled DNA synthesis of xeroderma pigmentosum cells and the amount of T4 endonuclease V activity added. The T4 enzyme was unstable in human cells, and its half-life was 3 hr. Fractions derived from an extract of Escherichia coli infected with T4V1, a mutant defective in the endonuclease V gene, showed no ability to restore the UV-induced unscheduled DNA synthesis of xeroderma pigmentosum cells. However, fractions derived from an extract of T4D-infected E. coli with endonuclease V activity were effective. The T4 enzyme was effective in xeroderma pigmentosum cells on DNA damaged by UV light but not in cells damaged by 4-nitroquinoline 1-oxide. The results of these experiments show that the T4 enzyme has a specific action on human cell DNA in vivo. Treatment with the T4 enzyme increased the survival of group A xeroderma pigmentosum cells after UV irradiation.