耐辐射球菌锰离子转运蛋白基因DR1709的完全删除分析

Analysis on the Complete Deletion of Mercury Ion Transporter Gene DR1709 in Deinococcus radiodurans

[目的]研究耐辐射球菌锰离子转运蛋白基因DR1709完全删除所造成的影响。[方法]试验构建DR1709完全删除突变体PM1709,并对其进行紫外线处理。[结果]在紫外线照射剂量为0和100 J/m2时,耐辐射球菌野生型、M1709和PM1709的存活率基本没有差别;从200 J/m2开始,突变体的存活率显著低于野生型;在含有200 nmol/L Mn的DMM中,M1709和PM1709几乎不能生长。在DMM平板上31℃下培养13 d后,仍然见不到M1709有任何生长的迹象。[结论]DR1709被删除以后,耐辐射球菌对紫外线的抗性显著降低,DR1709在耐辐射球菌抗辐射的过程中发挥了重要作用,DR1709部分删除突变体和完全删除突变体对紫外线的抗性几乎没有差别,说明M1709虽然只是部分删除了DR1709的基因序列,但DR1709的功能在M1709中已完全丧失;M1709对低剂量的锰离子十分敏感,但M1709在TGY中能够生长,说明在营养液中含有丰富的锰离子时,有其他基因代替DR1709行使吸收锰离子的功能,但当外界锰离子含量低时,DR1709则是唯一行使该功能的基因。

[ Objective ] To study the influence brought by the complete delection of mercury ion transporter gene DR1709 in Deinococcus radio- durans. [ Method] DR1709 was wholly deleted, PM1709 was constructed and then treated by UV. [ Result] When treated with 0 and 100 J/m2 UV, wild type, M1709 and PMIT09 had the similar surviving rate. When treated with more than 200 J/m2 , the surviving rate of the mutants was much lower than that of the wild type. In DMM containing 200 nmol/L Mn, neither M1709 nor PM1709 can grow. When cultured at 31℃ for 13 d on the DMM plate, there is still no growth sign of M1709. [Conclusion] When DR1709 was deleted, the resistance of D. radiodurans to UV declined significantly, indicating that dr1709 plays an important role in the radio resistance of D. radiodurans. M1709 and PM1709 had the similar surviving rate, indicating that DR1709＇ s function has been deleted fully in M1709, although only partial sequence had been deleted. M1709 and PM1709 were very sensitive to low-content mercury ions. However, M1709 can grow in TGY, suggesting that there were other genes that can substitute DRI709 when the medium had high-content mercury, but when the mercury ion content was low, DR1709 was the only gene that can play such roles.