title: Identification of the Phr-dependent heat shock regulon in the hyperthermophilic archaeon, Thermococcus kodakaraensis.
abstract: The hyperthermophilic archaeon Thermococcus kodakaraensis harbors a putative transcriptional regulator (Tk-Phr) that is orthologous to the Pyrococcus furiosus Phr (Pf-Phr). Pf-Phr, a transcriptional regulator, represses genes encoding the small heat shock protein (sHSP), AAA(+) ATPase and Pf-Phr itself under normal growth temperatures. Here we constructed a gene disruption strain of Tk-Phr (strain KHR1). KHR1 cells showed similar specific growth rates with those of the wild-type strain under various temperatures. A whole genome microarray analysis was performed between KHR1 and wild-type cells grown at 80 degrees C. Transcript levels of more than 20 genes were significantly higher in KHR1 cells. Most genes contained a sequence motif virtually identical to that of Pf-Phr in their 5'-flanking regions. The Tk-Phr regulon included genes encoding sHSP, AAA(+) ATPase, prefoldin, RecA superfamily ATPase and Tip49. On the other hand, more than half of the members in the regulon encoded conserved/hypothetical proteins, raising the possibility that these proteins participate in unidentified processes of the heat shock response. In contrast, Tk-Phr deletion did not lead to dramatic increase in transcript and protein levels of a chaperonin (CpkB) previously shown to respond to heat shock, suggesting the presence of a second, Phr-independent heat shock response mechanism in T. kodakaraensis.
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, Japan.
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Kanai
authors.forename: Shogo
authors.initials: S
authors.lastname: Takedomi
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Fujiwara
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Atomi
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Imanaka
mesh_terms: D000251:Adenosine Triphosphatases / Q000096:biosynthesis / Q000235:genetics; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D019766:Genes, Archaeal; D005809:Genes, Regulator; D050888:Heat-Shock Proteins, Small / Q000096:biosynthesis / Q000235:genetics; D018869:Heat-Shock Response / Q000235:genetics*; D018832:Molecular Chaperones / Q000096:biosynthesis / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D018085:Regulon; D013696:Temperature; D019712:Thermococcus / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*
chemical_list: D050888:Heat-Shock Proteins, Small; D018832:Molecular Chaperones; C112806:prefoldin; D000251:Adenosine Triphosphatases