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HtpG is essential for the thermal stress management in cyanobacteria
Author(s) -
Tanaka Naoki,
Nakamoto Hitoshi
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01134-5
Subject(s) - biology , mutant , mutagenesis , gene , heat shock protein , synechococcus , cyanobacteria , adaptation (eye) , mutation , genetics , wild type , microbiology and biotechnology , hsp90 , bacteria , neuroscience
The heat shock protein (Hsp) HtpG is a member of the Hsp90 protein family. We cloned a single‐copy gene encoding a homologue of HtpG from the unicellular cyanobacterium Synechococcus sp. PCC 7942. Sequence alignment with HtpGs from other prokaryotes revealed unique features in the cyanobacterial HtpG primary sequence. A monocistronic mRNA of the htpG gene increased transiently in response to heat shock. In order to elucidate the role of HtpG in vivo, we inactivated the htpG gene by targeted mutagenesis. Although the mutation did not affect the photoautotrophic growth at 30 and 42°C, the mutant cells were unable to grow at 45°C. They lost both basal and acquired thermotolerances. These results indicate that HtpG plays an essential role for the thermal stress management in cyanobacteria, the first such an example for either a photosynthetic or a prokaryotic organism.