Open AccessInvolvement of CarA/LitR and CRP/FNR Family Transcriptional Regulators in Light-Induced Carotenoid Production in Thermus thermophilus
Author(s) -
Hideaki Takano,
Masato Kondo,
Noriyoshi Usui,
Toshimitsu Usui,
Hiromichi Ohzeki,
Ryuta Yamazaki,
Misato Washioka,
Akira Nakamura,
Takayuki Hoshino,
Wataru Hakamata,
Teruhiko Beppu,
Kenji Uéda
Publication year - 2011
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.01125-10
Subject(s) - biology , operon , thermus thermophilus , phytoene synthase , genetics , regulator gene , mutant , regulation of gene expression , gene , gene expression , escherichia coli
Members of the CarA/LitR family are MerR-type transcriptional regulators that contain a C-terminal cobalamin-binding domain. They are thought to be involved in light-induced transcriptional regulation in a wide variety of nonphototrophic bacteria. Based on the distribution of this kind of regulator, the current study examined carotenoid production inThermus thermophilus , and it was found to occur in a light-induced manner.litR and carotenoid and cobalamin biosynthesis genes were all located on the large plasmid of this organism.litR or cobalamin biosynthesis gene knockout mutants were unable to switch off carotenoid production under dark conditions, while a mutant with a mutation in the downstream gene adjacent tolitR (TT_P0055), which encodes a CRP/FNR family transcriptional regulator, was unable to produce carotenoids, irrespective of light conditions. Overall, genetic and biochemical evidence indicates that LitR is bound by cobalamin and associates with the intergenic promoter region betweenlitR andcrtB (phytoene synthase gene), repressing the bidirectional transcription oflitR andcrtB . It is probable that derepression of LitR caused by some photodependent mechanism induces the expression of TT_P0055 protein, which serves as a transcriptional activator for thecrtB operon and hence causes the expression of carotenoid biosynthesis and the DNA repair system under light condition.