Deletion of the topoisomeraseⅢgene in the hyperthermophilic archaeon Sulfolobus islandicus results in slow growth and defects in cell cycle control  

作　　者：Xiyang Li Li Guo Ling Deng Deqin Feng Yi Ren Yindi Chu Qunxin She Li Huang 

机构地区：[1]State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China [2]Archaea Centre, Department of Biology, Copenhagen University, Ole Maalces Vej 5, DK-2200N Copenhagen, Denmark

出　　处：《Journal of Genetics and Genomics》2011年第6期253-259,共7页遗传学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.30921065,30730003 and 30870058) to L.Huang;the Danish Research Council for Technology and Production(No.274-07-0116)

摘　　要：Topoisomerase III （topo III）, a type IA topoisomerase, is widespread in hyperthermophilic archaea. In order to interrogate the in vivo role of archaeal topo III, we constructed and characterized a topo III gene deletion mutant of Sulfolobus islandicus. The mutant was ,viable but grew more slowly than the wild-type strain, especially in a nutrient-poor medium. Flow cytometry analysis revealed changes of the mutant in growth cycle characteristics including an increase in proportion of cells containing either more than two genome equivalents or less than one genome equivalent in exponentially-growing cultures. As shown by fluorescence microscopy, a fraction of mutant cells in the cultures were drastically enlarged, and at least some of the enlarged cells were apparently capable of resuming cell division. The mutant also shows a different tran- scriptional profile from that of the wild-type strain. Our results suggest that the enzyme may serve roles in chromosomal segregation and control of the level of supercoiling in the cell.Topoisomerase III （topo III）, a type IA topoisomerase, is widespread in hyperthermophilic archaea. In order to interrogate the in vivo role of archaeal topo III, we constructed and characterized a topo III gene deletion mutant of Sulfolobus islandicus. The mutant was ,viable but grew more slowly than the wild-type strain, especially in a nutrient-poor medium. Flow cytometry analysis revealed changes of the mutant in growth cycle characteristics including an increase in proportion of cells containing either more than two genome equivalents or less than one genome equivalent in exponentially-growing cultures. As shown by fluorescence microscopy, a fraction of mutant cells in the cultures were drastically enlarged, and at least some of the enlarged cells were apparently capable of resuming cell division. The mutant also shows a different tran- scriptional profile from that of the wild-type strain. Our results suggest that the enzyme may serve roles in chromosomal segregation and control of the level of supercoiling in the cell.

关 键 词：Hyperthermophilic archaea Sulfolobus islandicus Topoisomerase III topA deletion PHENOTYPE 

分 类 号：Q253[生物学—细胞生物学] O621.25[理学—有机化学]