Correction: an operon of three transcriptional regulators controls horizontal gene transfer of the integrative and conjugative element ICEclc in Pseudomonas knackmussii B13.
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ABSTRACT:
SUBMITTER: PLOS Genetics Staff
PROVIDER: S-EPMC4393261 | biostudies-literature | 2015 Apr
REPOSITORIES: biostudies-literature
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Correction: an operon of three transcriptional regulators controls horizontal gene transfer of the integrative and conjugative element ICEclc in Pseudomonas knackmussii B13.
PLoS genetics 20150410 4
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Project description:The integrative and conjugative element ICEclc is a mobile genetic element in Pseudomonas knackmussii B13, and an experimental model for a widely distributed group of elements in Proteobacteria. ICEclc is transferred from specialized transfer competent cells, which arise at a frequency of 3-5% in a population at stationary phase. Very little is known about the different factors that control the transfer frequency of this ICE family. Here we report the discovery of a three-gene operon encoded by ICEclc, which exerts global control on transfer initiation. The operon consists of three consecutive regulatory genes, encoding a TetR-type repressor MfsR, a MarR-type regulator and a LysR-type activator TciR. We show that MfsR autoregulates expression of the operon, whereas TciR is a global activator of ICEclc gene expression, but no clear role was yet found for MarR. Deletion of mfsR increases expression of tciR and marR, causing the proportion of transfer competent cells to reach almost 100% and transfer frequencies to approach 1 per donor. mfsR deletion also caused a two orders of magnitude loss in population viability, individual cell growth arrest and loss of ICEclc. This indicates that autoregulation is an important feature maintaining ICE transfer but avoiding fitness loss. Bioinformatic analysis showed that the mfsR-marR-tciR operon is unique for ICEclc and a few highly related ICE, whereas tciR orthologues occur more widely in a large variety of suspected ICE among Proteobacteria.
| S-EPMC4063739 | biostudies-literature
Project description:Integrative conjugative elements (ICE) are a diverse group of chromosomally integrated, self-transmissible mobile genetic elements (MGE) that are active in shaping the functions of bacteria and bacterial communities. Each type of ICE carries a characteristic set of core genes encoding functions essential for maintenance and self-transmission, and cargo genes that endow on hosts phenotypes beneficial for niche adaptation. An important area to which ICE can contribute beneficial functions is the biodegradation of xenobiotic compounds. In the biodegradation realm, the best-characterized ICE is ICEclc, which carries cargo genes encoding for ortho-cleavage of chlorocatechols (clc genes) and aminophenol metabolism (amn genes). The element was originally identified in the 3-chlorobenzoate-degrader Pseudomonas knackmussii B13, and the closest relative is a nearly identical element in Burkholderia xenovorans LB400 (designated ICEclc-B13 and ICEclc-LB400, respectively). In the present report, genome sequencing of the o-chlorobenzoate degrader Pseudomonas aeruginosa JB2 was used to identify a new member of the ICEclc family, ICEclc-JB2. The cargo of ICEclc-JB2 differs from that of ICEclc-B13 and ICEclc-LB400 in consisting of a unique combination of genes that encode for the utilization of o-halobenzoates and o-hydroxybenzoate as growth substrates (ohb genes and hyb genes, respectively) and which are duplicated in a tandem repeat. Also, ICEclc-JB2 lacks an operon of regulatory genes (tciR-marR-mfsR) that is present in the other two ICEclc, and which controls excision from the host. Thus, the mechanisms regulating intracellular behavior of ICEclc-JB2 may differ from that of its close relatives. The entire tandem repeat in ICEclc-JB2 can excise independently from the element in a process apparently involving transposases/insertion sequence associated with the repeats. Excision of the repeats removes important niche adaptation genes from ICEclc-JB2, rendering it less beneficial to the host. However, the reduced version of ICEclc-JB2 could now acquire new genes that might be beneficial to a future host and, consequently, to the survival of ICEclc-JB2. Collectively, the present identification and characterization of ICEclc-JB2 provides insights into roles of MGE in bacterial niche adaptation and the evolution of catabolic pathways for biodegradation of xenobiotic compounds.
| S-EPMC6050381 | biostudies-literature
Project description:Integrative and conjugative elements (ICEs) are chromosomally integrated self-transmissible mobile genetic elements. Although some ICEs are known to carry genes for the degradation of aromatic compounds, information on their genetic features is limited. We identified a new member of the ICEclc family carrying biphenyl catabolic bph genes and salicylic acid catabolic sal genes from the PCB-degrading strain Pseudomonas stutzeri KF716. The 117-kb ICEbph-salKF716 contains common core regions exhibiting homology with those of degradative ICEclc from P. knackmussii B13 and ICEXTD from Azoarcus sp. CIB. A comparison of the gene loci collected from the public database revealed that several putative ICEs from P. putida B6-2, P, alcaliphila JAB1, P. stutzeri AN10, and P. stutzeri 2A20 had highly conserved core regions with those of ICEbph-salKF716, along with the variable region that encodes the catabolic genes for biphenyl, naphthalene, toluene, or phenol. These data indicate that this type of ICE subfamily is ubiquitously distributed within aromatic compound-degrading bacteria. ICEbph-salKF716 was transferred from P. stutzeri KF716 to P. aeruginosa PAO1 via a circular extrachromosomal intermediate form. In this study, we describe the structure and genetic features of ICEbph-salKF716 compared to other catabolic ICEs.
| S-EPMC8704644 | biostudies-literature
Project description:BACKGROUND: Integrative and conjugative elements (ICE) form a diverse group of DNA elements that are integrated in the chromosome of the bacterial host, but can occasionally excise and horizontally transfer to a new host cell. ICE come in different families, typically with a conserved core for functions controlling the element's behavior and a variable region providing auxiliary functions to the host. The ICEclc element of Pseudomonas knackmussii strain B13 is representative for a large family of chromosomal islands detected by genome sequencing approaches. It provides the host with the capacity to degrade chloroaromatics and 2-aminophenol. RESULTS: Here we study the transcriptional organization of the ICEclc core region. By northern hybridizations, reverse-transcriptase polymerase chain reaction (RT-PCR) and Rapid Amplification of cDNA Ends (5'-RACE) fifteen transcripts were mapped in the core region. The occurrence and location of those transcripts were further confirmed by hybridizing labeled cDNA to a semi-tiling micro-array probing both strands of the ICEclc core region. Dot blot and semi-tiling array hybridizations demonstrated most of the core transcripts to be upregulated during stationary phase on 3-chlorobenzoate, but not on succinate or glucose. CONCLUSIONS: The transcription analysis of the ICEclc core region provides detailed insights in the mode of regulatory organization and will help to further understand the complex mode of behavior of this class of mobile elements. We conclude that ICEclc core transcription is concerted at a global level, more reminiscent of a phage program than of plasmid conjugation.
| S-EPMC2892462 | biostudies-literature
Project description:Conjugation of DNA relies on multicomponent protein complexes bridging two bacterial cytoplasmic compartments. Whereas plasmid conjugation systems have been well documented, those of integrative and conjugative elements (ICEs) have remained poorly studied. We characterize here the conjugation system of the ICEclc element in Pseudomonas putida UWC1 that is a model for a widely distributed family of ICEs. By in frame deletion and complementation, we show the importance on ICE transfer of 22 genes in a 20-kb conserved ICE region. Protein comparisons recognized seven homologs to plasmid type IV secretion system components, another six homologs to frequent accessory proteins, and the rest without detectable counterparts. Stationary phase imaging of P. putida ICEclc with in-frame fluorescent protein fusions to predicted type IV components showed transfer-competent cell subpopulations with multiple fluorescent foci, largely overlapping in dual-labeled subcomponents, which is suggestive for multiple conjugation complexes per cell. Cross-dependencies between subcomponents in ICE-type IV secretion system assembly were revealed by quantitative foci image analysis in a variety of ICEclc mutant backgrounds. In conclusion, the ICEclc family presents an evolutionary distinct type IV conjugative system with transfer competent cells specialized in efficient transfer.
| S-EPMC10018362 | biostudies-literature
Project description:These transcriptomic data are used in two distinct but subsequent and complementary studies:(i) the role of the mfsR gene on the expression of the mfsABC operon as well as on its own promoter, (ii) the role of the mfsR operon on the activation of the core genes of ICEclc.
2014-09-01 | GSE51391 | GEO
Project description:These transcriptomic data are used in two distinct but subsequent and complementary studies:(i) the role of the mfsR gene on the expression of the mfsABC operon as well as on its own promoter, (ii) the role of the mfsR operon on the activation of the core genes of ICEclc. ICEclc-specific gene expression in Pseudomonas putida UWC1 was measured during exponential phase and the subsequent stationary phase (sole carbon and energy sources : 10mM 3-chlorobenzoate). 6 genotypes were tested: (i) wild type P. putida UWC1 ICEclc (strain nM-BM-02737) ; (ii) P. putida UWC1 ICEclc-KmR19033 (strain nM-BM-02961) ; (iii) P. putida UWC1 ICEclcM-bM-^HM-^F'mfsR (strain nM-BM-04322) ; (iv) P. putida UWC1 ICEclcM-bM-^HM-^F'orf17984 (strain nM-BM-04372) ; (v) P. putida UWC1 ICEclcM-bM-^HM-^F'tciR (strain nM-BM-04321) ; (vi) P. putida UWC1 ICEclcM-bM-^HM-^FmfsR-M-bM-^HM-^F'orf17984 (strain nM-BM-03543). For each strain, in each phase, 3 or 4 replicates were used.
2014-09-01 | E-GEOD-51391 | biostudies-arrayexpress
Project description:The extensive use of petrochemicals has produced serious environmental pollution problems; fortunately, bioremediation is considered an efficient way to fight against pollution. In line with Synthetic Biology is that robust microbial chassis with an expanded ability to remove environmental pollutants are desirable. Pseudomonas putida KT2440 is a robust lab microbe that has preserved the ability to survive in the environment and is the natural host for the self-transmissible TOL plasmid, which allows metabolism of toluene and xylenes to central metabolism. We show that the P. putida KT2440 (pWW0) acquired the ability to use octane as the sole C-source after acquisition of an almost 62-kb ICE from a microbial community that harbours an incomplete set of octane metabolism genes. The ICE bears genes for an alkane monooxygenase, a PQQ-dependent alcohol dehydrogenase and aldehyde dehydrogenase but lacks the electron donor enzymes required for the monooxygenase to operate. Host rubredoxin and rubredoxin reductase allow metabolism of octane to octanol. Proteomic assays and mutants unable to grow on octane or octanoic acid revealed that metabolism of octane is mediated by redundant host and ICE enzymes. Octane is oxidized to octanol, octanal and octanoic acid, the latter is subsequently acylated and oxidized to yield acetyl-CoA that is assimilated via the glyoxylate shunt; in fact, a knockout mutant in the aceA gene, encoding isocitrate lyase was unable to grow on octane or octanoic acid.
| S-EPMC9795978 | biostudies-literature
Project description:To support our molecular hypothesis of the effect of rpoS and inrR genes over the activation of the ICEclc genome in Pseudomonas knackmussii B13, we have employed Agilent DNA custom microarray in the 8X15K format. ICEclc-specific gene expression in Pseudomonas knackmussii strain B13 was measured after 48 hours of stationary phase following a growth on 10mM 3-chlorobenzoate (3CBA) as sole carbon and energy source. Various genotypes were tested: wild type (strain nM-BM-078, in 5 replicates), inrR-/- (strain 2201, in triplicates), delta::rpoS (strain 2671, in triplicates).
2012-09-01 | E-GEOD-35501 | biostudies-arrayexpress
Project description:To support our molecular hypothesis of the effect of rpoS and inrR genes over the activation of the ICEclc genome in Pseudomonas knackmussii B13, we have employed Agilent DNA custom microarray in the 8X15K format.
2012-09-01 | GSE35501 | GEO