Premium
Treponema denticola TroR is a manganese‐ and iron‐dependent transcriptional repressor
Author(s) -
Brett Paul J.,
Burtnick Mary N.,
Fenno J. Christopher,
Gherardini Frank C.
Publication year - 2008
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2008.06418.x
Subject(s) - treponema denticola , operon , biology , repressor , treponema , genetics , gene , locus (genetics) , homology (biology) , microbiology and biotechnology , promoter , escherichia coli , transcription factor , bacteria , gene expression , virology , porphyromonas gingivalis , syphilis , human immunodeficiency virus (hiv)
Summary Treponema denticola harbours a genetic locus with significant homology to most of the previously characterized Treponema pallidum tro operon. Within this locus are five genes ( troABCDR ) encoding for the components of an ATP‐binding cassette cation‐transport system ( troABCD ) and a DtxR‐like transcriptional regulator ( troR ). In addition, a σ 70 ‐like promoter and an 18 bp region of dyad symmetry were identified upstream of the troA start codon. This putative operator sequence demonstrated similarity to the T. pallidum TroR (TroR Tp ) binding sequence; however, the position of this motif with respect to the predicted tro promoters differed. Interestingly, unlike the T. pallidum orthologue, T. denticola TroR (TroR Td ) possesses a C‐terminal Src homology 3‐like domain commonly associated with DtxR family members. In the present study, we show that TroR Td is a manganese‐ and iron‐dependent transcriptional repressor using Escherichia coli reporter constructs and in T. denticola . In addition, we demonstrate that although TroR Td possessing various C‐terminal deletions maintain metal‐sensing capacities, these truncated proteins exhibit reduced repressor activities in comparison with full‐length TroR Td . Based upon these findings, we propose that TroR Td represents a novel member of the DtxR family of transcriptional regulators and is likely to play an important role in regulating both manganese and iron homeostases in this spirochaete.