Lombardo Mary-Jane, Aponyi Ildiko, Ray Mellanie P, Sandigursky Margarita, Franklin William A, Rosenberg Susan M
Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Rm S809A Mail Stop BCM225, Houston, TX 77030-3411, USA.
DNA Repair (Amst). 2003 Nov 21;2(11):1175-83. doi: 10.1016/s1568-7864(03)00135-6.
Single-strand-dependent DNA exonucleases play important roles in DNA repair and recombination in all organisms. In Escherichia coli the redundant functions provided by the RecJ, ExoI, ExoVII and ExoX exonucleases are required for mismatch repair, UV resistance and homologous recombination. We have examined whether the xni gene product, the single-strand exonuclease ExoIX, is also a member of this group. We find that deletion of xni has no effect on the above processes, or on resistance to oxidative damage, even in combination with other exonuclease mutations. We conclude that the xni gene product does not belong to this group of nucleases that play redundant roles in DNA recombination and repair.
单链依赖性DNA核酸外切酶在所有生物体的DNA修复和重组中发挥着重要作用。在大肠杆菌中，RecJ、ExoI、ExoVII和ExoX核酸外切酶提供的冗余功能对于错配修复、紫外线抗性和同源重组是必需的。我们研究了单链核酸外切酶ExoIX的xni基因产物是否也是该组的成员。我们发现，即使与其他核酸外切酶突变结合，xni的缺失对上述过程或氧化损伤抗性也没有影响。我们得出结论，xni基因产物不属于在DNA重组和修复中起冗余作用的这组核酸酶。
