极端嗜热古菌核酸内切酶Ⅲ的研究进展

Research progress in endonuclease Ⅲ of hyperthermophilic archaea

摘要:

胸腺嘧啶乙二醇(thymine glycol，Tg)是常见的氧化性DNA损伤碱基之一。DNA中的Tg能够分别阻止DNA聚合酶和RNA聚合酶进行DNA复制和转录，导致相应的生物学过程终止，进而会引起细胞的死亡，因此DNA中的Tg需要被修复。核酸内切酶Ⅲ(endonuclease Ⅲ，EndoⅢ)是一种双功能DNA糖苷酶，能够切除DNA中的Tg，从而启动碱基切除修复途径进行修复DNA中的Tg。细菌、古菌和真核生物的基因组序列中均存在有EndoⅢ蛋白的编码基因。目前，源自于细菌和真核生物的EndoⅢ已有较多的研究，而古菌EndoⅢ的研究相对较少。基于目前已有的极端嗜热古菌EndoⅢ的研究报道，本文综述了极端嗜热古菌EndoⅢ的研究进展，并展望了今后的研究方向。

Abstract:

Thymine glycol (Tg) is one of the common oxidative DNA damage bases. It can stall DNA polymerase and RNA polymerase that perform DNA replication and transcription, thus leading to the termination of the corresponding biological processes and further causing cell death. Therefore, Tg in DNA needs to be repaired. Endonuclease Ⅲ (EndoⅢ) is a bifunctional DNA glycosylase capable of excising Tg from DNA, thus initiating a base excision repair pathway for restoring Tg to a normal T base. The genomes of bacteria, archaea, and eukaryotes possess the gene encoding EndoⅢ. The available studies mainly focus on the EndoⅢ in bacteria and eukaryotes while rarely concern archaeal EndoⅢ. We reviewed the research progress on the EndoⅢ in hyperthermophilic archaea and proposed the future research directions in this field.