盐生盐杆菌启动子DNA片段的特征序列及其功能分析

Sequence Characteristic and Function of DNA Fragments Active as Bacteria Promoter from Archaea

利用启动子探针质粒 p KK2 3 2 - 8从古菌盐生盐杆菌中分离到许多具有细菌基因启动子功能的 DNA片段 .对其中 3个片段 RM0 7、RM0 8和 RM13的序列测定 ,发现这 3个片段上均具有典型的细菌基因启动子的保守序列 ( - 3 5和 - 10区 ) ,其中的 2个片段 RM0 7和 RM13还分别具有古菌或真核生物启动子的典型特征序列 .利用大肠杆菌 -酵母菌启动子探针穿梭载体 p YL Z- 2将 3个片段分别导入大肠杆菌和酵母菌中 ,通过检测 ( -半乳糖苷酶活性 ,进一步从功能上获得了确证 .这是首次从结构和功能上发现并证实了来自古菌的 DNA片段上具有二界或三界生物的特征 ,从而为进一步揭示古菌之谜和丰富生物的系统发育和进化关系提供了新的信息和途径 ,并有可能为构建双功能表达载体提供新的启动子来源 .此外 ,在所获得的 3个片段上还发现了类似于细菌σ54启动子的典型序列 ,这是否暗示古菌为了适应极端环境所进行的转录调控有关 ,还有待进一步的研究 .

DNA fragments active as bacteria gene promoters from Archaea Halobacterium Halobium were isolated by the promoter-probe plasmid pKK232-8. Sequencing of three fragments of them, which are named RM07, RM08 and RM13, proved that there are typical consensus sequences (-35 and -10) of bacteria gene promoter in these fragments. Moreover, it is found that the fragments RM07 and RM13 contain promoter characteristic sequences similar to eukayota or archaea. These isolated DNA fragments were confirmed farther their function by transforming RM07, RM08 and RM13 respectively into E.coli and Saccharomyces cerevisiae Ay using shuttle vector pYLZ-2 (also, promoter-probe plasmid) and determining of activity of β-galactosidase coded by report gene lacZ. It is the first found and firmed that An archaeal genome contains DNA fragments with two or three kingdomes characteristic showing promoter activity. Therefore, new information and approach are provided for exposing farther archaeal puzzles and its revolution relationship. It is possible to provide novel promoter source for constructing double-function vector. In addition, typical σ 54 promoter sequences similar to bacteria were found on the three DNA fragments. It have remain get to be researched whether or not these segments are responsible for regulating of transcription under extremely environment in archaea.