HspA and HtpG enhance thermotolerance in the cyanobacterium, Microcystis aeruginosa NIES-298.
Heat shock proteins (Hsps) play a key role in the cellular defense response to diverse environmental stresses. Here, the role of Hsp genes in the acquisition of thermotolerance in the cyanobacterium Microcystis aeruginosa NIES-298 was investigated. Twelve Hsp-related genes were examined to observe their modulated expression patterns at different temperatures (10, 15, 25, and 35° C) over different exposure periods. HspA and HtpG transcripts showed an up-regulation of expression at low temperatures (10 and 15° C) and high temperature (35° C), compared with the control (25° C). To examine their effects upon thermotolerance, we purified recombinant HspA and HtpG proteins. During a thermotolerance study at 54° C, the HspA-transformed bacteria showed increased thermotolerance compared with the control. HtpG also played a role in the defense response to acute heat stress within 30 min. These findings provide a better understanding of cellular protection mechanisms against heat stress in cyanobacteria.
Department of Molecular and Environmental Bioscience, Graduate School, Hanyang University, Seoul 133-791, Korea.
Jae-Sung
JS
Rhee
Jang-Seu
JS
Ki
Bo-Mi
BM
Kim
Soon-Jin
SJ
Hwang
Ik-Young
IY
Choi
Jae-Seong
JS
Lee
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D020869:Gene Expression Profiling; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D050296:Microbial Viability / Q000528:radiation effects; D046931:Microcystis / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects*; D011994:Recombinant Proteins / Q000302:isolation & purification
D001426:Bacterial Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C113725:HspA protein, bacteria; D011994:Recombinant Proteins; C066720:HtpG protein, bacteria