Novel TetR family transcriptional factor regulates expression of multiple transport-related genes and affects rifampicin resistance in Mycobacterium smegmatis

Liu, Huicong; Yang, Min; He, Zheng‐Guo

doi:10.1038/srep27489

Cited by 14 publications

(10 citation statements)

References 31 publications

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“…Also, of the 4 proteins identified as down regulated (absent in treated samples) in time point three, two are predicted transporters of the major facilitator superfamily. A recent study identified Ms4022 (MSMEG_4022) as a novel TetR-family regulator that directly activates the expression of seven transport related genes and enhanced M. smegmatis resistance to anti-tuberculosis drugs including rifampicin 34 . In the current study however Ms4022 did not significantly differ between treatment and control groups across all three time points (see Supplementary Spreadsheet S1 ).…”

Section: Resultsmentioning

confidence: 99%

A temporal proteome dynamics study reveals the molecular basis of induced phenotypic resistance in Mycobacterium smegmatis at sub-lethal rifampicin concentrations

Giddey

Kock

Nakedi

et al. 2017

Sci Rep

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In the last 40 years only one new antitubercular drug has been approved, whilst resistance to current drugs, including rifampicin, is spreading. Here, we used the model organism Mycobacterium smegmatis to study mechanisms of phenotypic mycobacterial resistance, employing quantitative mass spectrometry-based proteomics to investigate the temporal effects of sub-lethal concentrations of rifampicin on the mycobacterial proteome at time-points corresponding to early response, onset of bacteriostasis and early recovery. Across 18 samples, a total of 3,218 proteins were identified from 31,846 distinct peptides averaging 16,250 identified peptides per sample. We found evidence that two component signal transduction systems (e.g. MprA/MprB) play a major role during initial mycobacterial adaptive responses to sub-lethal rifampicin and that, after dampening an initial SOS response, the bacteria supress the DevR (DosR) regulon and also upregulate their transcriptional and translational machineries. Furthermore, we found a co-ordinated dysregulation in haeme and mycobactin synthesis. Finally, gradual upregulation of the M. smegmatis-specific rifampin ADP-ribosyl transferase was observed which, together with upregulation of transcriptional and translational machinery, likely explains recovery of normal growth. Overall, our data indicates that in mycobacteria, sub-lethal rifampicin triggers a concerted phenotypic response that contrasts significantly with that observed at higher antimicrobial doses.

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Section: Resultsmentioning

confidence: 99%

A temporal proteome dynamics study reveals the molecular basis of induced phenotypic resistance in Mycobacterium smegmatis at sub-lethal rifampicin concentrations

Giddey

Kock

Nakedi

et al. 2017

Sci Rep

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“…Other TFTRs are activators [7] and some can act as both activators and repressors [8]. TFTRs have been identified which can bind multiple targets [9, 10] and intergenic regions [11]. Thus, although some TFTRs are known to be local repressors, the current classification system is, in some cases, oversimplifying these proteins.…”

Section: Introductionmentioning

confidence: 99%

TetR-family transcription factors in Gram-negative bacteria: conservation, variation and implications for efflux-mediated antimicrobial resistance

2019

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Background TetR-family transcriptional regulators (TFTRs) are DNA binding factors that regulate gene expression in bacteria. Well-studied TFTRs, such as AcrR, which regulates efflux pump expression, are usually encoded alongside target operons. Recently, it has emerged that there are many TFTRs which act as global multi-target regulators. Our classical view of TFTRs as simple, single-target regulators therefore needs to be reconsidered. As some TFTRs regulate essential processes (e.g. metabolism) or processes which are important determinants of resistance and virulence (e.g. biofilm formation and efflux gene expression) and as TFTRs are present throughout pathogenic bacteria, they may be good drug discovery targets for tackling antimicrobial resistant infections. However, the prevalence and conservation of individual TFTR genes in Gram-negative species, has to our knowledge, not yet been studied. Results Here, a wide-scale search for TFTRs in available proteomes of clinically relevant pathogens Salmonella and Escherichia species was performed and these regulators further characterised. The majority of identified TFTRs are involved in efflux regulation in both Escherichia and Salmonella. The percentage variance in TFTR genes of these genera was found to be higher in those regulating genes involved in efflux, bleach survival or biofilm formation than those regulating more constrained processes. Some TFTRs were found to be present in all strains and species of these two genera, whereas others (i.e. TetR) are only present in some strains and some (i.e. RamR) are genera-specific. Two further pathogens on the WHO priority pathogen list (K. pneumoniae and P. aeruginosa) were then searched for the presence of the TFTRs conserved in Escherichia and Salmonella. Conclusions Through bioinformatics and literature analyses, we present that TFTRs are a varied and heterogeneous family of proteins required for the regulation of numerous important processes, with consequences to antimicrobial resistance and virulence, and that the roles and responses of these proteins are frequently underestimated.

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“…Since the first report of the introduction of foreign DNA into M. smegmatis in 1987, M. smegmatis has been used as the workhorse of mycobacterial research and as a surrogate model for pathogenic and slower‐growing mycobacterial species such as M. leprae and M. tuberculosis (Liu, Yang, & He, ; Titgemeyer et al., ). In this study, M. smegmatis was utilized as a surrogate host for M. tuberculosis to further investigate the roles of DdlA in mycobacteria.…”

Section: Discussionmentioning

confidence: 99%

“…Fumonisin, a notorious mycotoxin, consists of aminopolyols with a core structure containing a 19-or 20-carbon backbone with methyl, hydroxyl, and tricarballylic acid moieties at different sites along the carbon backbone (Baird et al, 2008). Currently, accumulating evidence shows that fumonisin, which is a polyketide derivative and is structurally related to sphinganine, usually causes a variety of toxicological effects, such as esophageal cancer, cardiovascular problems, and neural tube defects, in humans and animals (Desjardins, Munkvold, Plattner, & Proctor, 2002;Waskiewicz, Stepien, Wilman, & Kachlicki, 2013 (Liu, Yang, & He, 2016;Titgemeyer et al, 2007). In this study, into anti-TB drug design to combat the difficult-to-treat pathogen M. tuberculosis.…”

Section: Discussionmentioning

confidence: 99%

Deficiency of D‐alanyl‐D‐alanine ligase A attenuated cell division and greatly altered the proteome of Mycobacterium smegmatis

Chen

Yang

et al. 2019

MicrobiologyOpen

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D‐Alanyl‐D‐alanine ligase A (DdlA) catalyses the dimerization of two D‐alanines yielding D‐alanyl‐D‐alanine required for mycobacterial peptidoglycan biosynthesis, and is a promising antimycobacterial drug target. To better understand the roles of DdlA in mycobacteria in vivo, we established a cell model in which DdlA expression was specifically downregulated by ddlA antisense RNA by introducing a 380 bp ddlA fragment into pMind followed by transforming the construct into nonpathogenic Mycobacterium smegmatis. The M. smegmatis cell model was verified by plotting the growth inhibition curves and quantifying endogenous DdlA expression using a polyclonal anti‐DdlA antibody produced from the expressed DdlA. Scanning electron microscopy and transmission electron microscopy were used to investigate mycobacterial morphology. Bidimensional gel electrophoresis and mass spectrometry were used to analyze differentially expressed proteins. Consequently, the successful construction of the M. smegmatis cell model was verified. The morphological investigation of the model indicated that DdlA deficiency led to an increased number of Z rings and a rearrangement of intracellular content, including a clear nucleoid and visible filamentous DNA. Proteomic techniques identified six upregulated and 14 downregulated proteins that interacted with each other to permit cell survival by forming a regulatory network under DdlA deficiency. Finally, our data revealed that DdlA deficiency inhibited cell division in mycobacteria and attenuated the process of carbohydrate catabolism and the pathway of fatty acid anabolism, while maintaining active protein degradation and synthesis. N‐Nitrosodimethylamine (NDMA)‐dependent methanol dehydrogenase (MSMEG_6242) and fumonisin (MSMEG_1419) were identified as potential antimycobacterial drug targets.

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Novel TetR family transcriptional factor regulates expression of multiple transport-related genes and affects rifampicin resistance in Mycobacterium smegmatis

Cited by 14 publications

References 31 publications

A temporal proteome dynamics study reveals the molecular basis of induced phenotypic resistance in Mycobacterium smegmatis at sub-lethal rifampicin concentrations

A temporal proteome dynamics study reveals the molecular basis of induced phenotypic resistance in Mycobacterium smegmatis at sub-lethal rifampicin concentrations

TetR-family transcription factors in Gram-negative bacteria: conservation, variation and implications for efflux-mediated antimicrobial resistance

Deficiency of D‐alanyl‐D‐alanine ligase A attenuated cell division and greatly altered the proteome of Mycobacterium smegmatis

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