Structure-Based Genetic Analysis of Hel308a in the Hyperthermophilic Archaeon Sulfolobus islandicus  

作　　者：Xueguo Song Jinfeng Ni Yulong Shen 

机构地区：[1]State Key Laboratory of Microbial Technology,Shandong University

出　　处：《Journal of Genetics and Genomics》2016年第6期405-413,共9页遗传学报（英文版）

基　　金：supported by the grants from the National Natural Science Foundation of China (Nos. 3093002, 31170072 and 31470184 to Y.S.)

摘　　要：In archaea, the HEL308 homolog Hel308a（or Hjm） is implicated in stalled replication fork repair. The biochemical properties and structures of Hjm homologs are well documented, but in vivo mechanistic information is limited. Herein, a structure-based functional analysis of Hjm was performed in the genetically tractable hyperthermophilic archaeon, Sulfolobus islandicus. Results showed that domain V and residues within it, which affect Hjm activity and regulation, are essential and that the domain V-truncated mutants and sitedirected mutants within domain V cannot complement hjm chromosomal deletion. Chromosomal hjm deletion can be complemented by ectopic expression of hjm under the control of its native promoter but not an artificial arabinose promoter. Cellular Hjm levels are kept constant under ultraviolet（UV） and methyl methanesulfonate（MMS） treatment conditions in a strain carrying a plasmid to induce Hjm overexpression. These results suggest that Hjm expression and activity are tightly controlled, probably at the translational level.In archaea, the HEL308 homolog Hel308a（or Hjm） is implicated in stalled replication fork repair. The biochemical properties and structures of Hjm homologs are well documented, but in vivo mechanistic information is limited. Herein, a structure-based functional analysis of Hjm was performed in the genetically tractable hyperthermophilic archaeon, Sulfolobus islandicus. Results showed that domain V and residues within it, which affect Hjm activity and regulation, are essential and that the domain V-truncated mutants and sitedirected mutants within domain V cannot complement hjm chromosomal deletion. Chromosomal hjm deletion can be complemented by ectopic expression of hjm under the control of its native promoter but not an artificial arabinose promoter. Cellular Hjm levels are kept constant under ultraviolet（UV） and methyl methanesulfonate（MMS） treatment conditions in a strain carrying a plasmid to induce Hjm overexpression. These results suggest that Hjm expression and activity are tightly controlled, probably at the translational level.

关 键 词：Archaea Hel308a Replication fork regression Genetic complementation Sulfolobus islandicus 

分 类 号：Q933[生物学—微生物学]