TY  - JOUR
A1  - Esken, Jens
A1  - Goris, Tobias
A1  - Gadkari, Jennifer
A1  - Bischler, Thorsten
A1  - Förstner, Konrad U.
A1  - Sharma, Cynthia M.
A1  - Diekert, Gabriele
A1  - Schubert, Torsten
T1  - Tetrachloroethene respiration in Sulfurospirillum species is regulated by a two‐component system as unraveled by comparative genomics, transcriptomics, and regulator binding studies
JF  - MicrobiologyOpen
N2  - Energy conservation via organohalide respiration (OHR) in dehalogenating Sulfurospirillum species is an inducible process. However, the gene products involved in tetrachloroethene (PCE) sensing and signal transduction have not been unambiguously identified. Here, genome sequencing of Sulfurospirillum strains defective in PCE respiration and comparative genomics, which included the PCE‐respiring representatives of the genus, uncovered the genetic inactivation of a two‐component system (TCS) in the OHR gene region of the natural mutants. The assumption that the TCS gene products serve as a PCE sensor that initiates gene transcription was supported by the constitutive low‐level expression of the TCS operon in fumarate‐adapted cells of Sulfurospirillum multivorans. Via RNA sequencing, eight transcriptional units were identified in the OHR gene region, which includes the TCS operon, the PCE reductive dehalogenase operon, the gene cluster for norcobamide biosynthesis, and putative accessory genes with unknown functions. The OmpR‐family response regulator (RR) encoded in the TCS operon was functionally characterized by promoter‐binding assays. The RR bound a cis‐regulatory element that contained a consensus sequence of a direct repeat (CTATW) separated by 17 bp. Its location either overlapping the −35 box or 50 bp further upstream indicated different regulatory mechanisms. Sequence variations in the regulator binding sites identified in the OHR gene region were in accordance with differences in the transcript levels of the respective gene clusters forming the PCE regulon. The results indicate the presence of a fine‐tuned regulatory network controlling PCE metabolism in dehalogenating Sulfurospirillum species, a group of metabolically versatile organohalide‐respiring bacteria.
KW  - genomics
KW  - organohalide respiration
KW  - RNA sequencing
KW  - tetrachloroethene
KW  - transcriptomics
KW  - two‐component system
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225754
VL  - 9
IS  - 12
ER  -