中文摘要：

真核DNA连接酶（DNA ligase）通过催化ATP依赖的双链DNA切口连接而在DNA复制、重组和修复过程中发挥了重要作用.DNA连接酶Ⅲ（Lig3）是一种独特性的连接酶,既可定位于细胞核,又可定位于线粒体.Lig3通过与DNA修复蛋白XRCC1作用而参与了碱基切除修复和其他单链断裂修复.但Lig3以XRCC1不依赖方式在线粒体DNA完整性保持方面发挥了更为重要的作用.这些研究为Lig3功能和DNA修复研究提供了新的视野.

英文摘要：

Eukaryotic DNA ligases play vital roles in DNA replication, recombination and repair through catalyzing ligation of nick in double-stranded DNA with an ATP-dependent reaction. DNA ligase Ⅲ （Lig3） is a unique ligase which is located in both nucleus and mitochondrion. Lig3 plays important roles in base excision repair and other single-stranded break repairs with its DNA repair protein XRCC 1. But Lig3 is more important in maintenance of mitochondrial DNA （mtDNA） integrity without XRCCl-dependent DNA repair. These researches provide new perspective for Lig3 function and DNA repair.