Golomb M, Grandgenett D P, Mason W
J Virol. 1981 May;38(2):548-55. doi: 10.1128/JVI.38.2.548-555.1981.
Reverse transcriptase from avian retrovirus has a physically associated DNA endonuclease with novel substrate and cofactor requirements. A similar endonuclease activity copurifies with pp32, a protein from viral cores that has been identified with the non-alpha region of the beta subunit of reverse transcriptase. Several temperature-sensitive mutants of avian retrovirus with thermolabile DNA polymerase were tested for thermal sensitivity of their DNA endonuclease activity. Two pol mutants of Rous sarcoma virus, ts335 and ts337, had thermolabile DNA endonuclease; a temperature-resistant revertant of ts335 had a heat-stable DNA endonuclease. DNA endonuclease is therefore a product of the pol gene and an integral part of the reverse transcriptase. A second class of pol mutants, typified by ts568 and ts553, had thermolabile DNA polymerase, but heat-stable DNA endonuclease.
来自禽逆转录病毒的逆转录酶与一种具有新底物和辅因子需求的物理相关DNA内切酶相关。一种类似的内切酶活性与pp32共纯化，pp32是一种来自病毒核心的蛋白质，已被鉴定与逆转录酶β亚基的非α区域有关。对几种具有热不稳定DNA聚合酶的禽逆转录病毒温度敏感突变体进行了DNA内切酶活性的热敏感性测试。劳氏肉瘤病毒的两个pol突变体ts335和ts337具有热不稳定的DNA内切酶；ts335的一个温度抗性回复株具有热稳定的DNA内切酶。因此，DNA内切酶是pol基因的产物，也是逆转录酶的一个组成部分。第二类pol突变体，以ts568和ts553为代表，具有热不稳定的DNA聚合酶，但具有热稳定的DNA内切酶。
