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Lizarralde-Guerrero M, Taraveau F. [Role of AcrAB-TolC multidrug efflux pump in drug-resistance acquisition by plasmid transfer]. Med Sci (Paris) 2021; 37:945-947. [PMID: 34647886 DOI: 10.1051/medsci/2021159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Florian Taraveau
- École normale supérieure de Lyon, Département de biologie, Master biologie, Lyon, France
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Hershberger CE, Moyer DC, Adema V, Kerr CM, Walter W, Hutter S, Meggendorfer M, Baer C, Kern W, Nadarajah N, Twardziok S, Sekeres MA, Haferlach C, Haferlach T, Maciejewski JP, Padgett RA. Complex landscape of alternative splicing in myeloid neoplasms. Leukemia 2020; 35:1108-1120. [PMID: 32753690 PMCID: PMC8101081 DOI: 10.1038/s41375-020-1002-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/08/2020] [Accepted: 07/22/2020] [Indexed: 12/31/2022]
Abstract
Myeloid neoplasms are characterized by frequent mutations in at least seven components of the spliceosome that have distinct roles in the process of pre-mRNA splicing. Hotspot mutations in SF3B1, SRSF2, U2AF1 and loss of function mutations in ZRSR2 have revealed widely different aberrant splicing signatures with little overlap. However, previous studies lacked the power necessary to identify commonly mis-spliced transcripts in heterogeneous patient cohorts. By performing RNA-Seq on bone marrow samples from 1,258 myeloid neoplasm patients and 63 healthy bone marrow donors, we identified transcripts frequently mis-spliced by mutated splicing factors (SF), rare SF mutations with common alternative splicing (AS) signatures, and SF-dependent neojunctions. We characterized 17,300 dysregulated AS events using a pipeline designed to predict the impact of mis-splicing on protein function. Meta-splicing analysis revealed a pattern of reduced levels of retained introns among disease samples that was exacerbated in patients with splicing factor mutations. These introns share characteristics with “detained introns,” a class of introns that have been shown to promote differentiation by detaining pro-proliferative transcripts in the nucleus. In this study, we have functionally characterized 17,300 targets of mis-splicing by the SF mutations, identifying a common pathway by which AS may promote maintenance of a proliferative state.
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Affiliation(s)
- Courtney E Hershberger
- Cardiovascular and Metabolic Sciences Department, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Devlin C Moyer
- Cardiovascular and Metabolic Sciences Department, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Vera Adema
- Department of Translational Hematology and Oncology Research, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Cassandra M Kerr
- Department of Translational Hematology and Oncology Research, Cleveland Clinic Foundation, Cleveland, OH, USA
| | | | | | | | | | | | | | | | - Mikkael A Sekeres
- Department of Translational Hematology and Oncology Research, Cleveland Clinic Foundation, Cleveland, OH, USA
| | | | | | - Jaroslaw P Maciejewski
- Department of Translational Hematology and Oncology Research, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Richard A Padgett
- Cardiovascular and Metabolic Sciences Department, Cleveland Clinic Foundation, Cleveland, OH, USA.
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Ectopic Expression of the ydaS and ydaT Genes of the Cryptic Prophage Rac of Escherichia coli K-12 May Be Toxic but Do They Really Encode Toxins?: a Case for Using Genetic Context To Understand Function. mSphere 2018; 3:3/2/e00163-18. [PMID: 29695625 PMCID: PMC5917428 DOI: 10.1128/msphere.00163-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Yamamoto K, Yamanaka Y, Shimada T, Sarkar P, Yoshida M, Bhardwaj N, Watanabe H, Taira Y, Chatterji D, Ishihama A. Altered Distribution of RNA Polymerase Lacking the Omega Subunit within the Prophages along the Escherichia coli K-12 Genome. mSystems 2018; 3:e00172-17. [PMID: 29468196 PMCID: PMC5811629 DOI: 10.1128/msystems.00172-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/25/2018] [Indexed: 11/20/2022] Open
Abstract
The RNA polymerase (RNAP) of Escherichia coli K-12 is a complex enzyme consisting of the core enzyme with the subunit structure α2ββ'ω and one of the σ subunits with promoter recognition properties. The smallest subunit, omega (the rpoZ gene product), participates in subunit assembly by supporting the folding of the largest subunit, β', but its functional role remains unsolved except for its involvement in ppGpp binding and stringent response. As an initial approach for elucidation of its functional role, we performed in this study ChIP-chip (chromatin immunoprecipitation with microarray technology) analysis of wild-type and rpoZ-defective mutant strains. The altered distribution of RpoZ-defective RNAP was identified mostly within open reading frames, in particular, of the genes inside prophages. For the genes that exhibited increased or decreased distribution of RpoZ-defective RNAP, the level of transcripts increased or decreased, respectively, as detected by reverse transcription-quantitative PCR (qRT-PCR). In parallel, we analyzed, using genomic SELEX (systemic evolution of ligands by exponential enrichment), the distribution of constitutive promoters that are recognized by RNAP RpoD holoenzyme alone and of general silencer H-NS within prophages. Since all 10 prophages in E. coli K-12 carry only a small number of promoters, the altered occupancy of RpoZ-defective RNAP and of transcripts might represent transcription initiated from as-yet-unidentified host promoters. The genes that exhibited transcription enhanced by RpoZ-defective RNAP are located in the regions of low-level H-NS binding. By using phenotype microarray (PM) assay, alterations of some phenotypes were detected for the rpoZ-deleted mutant, indicating the involvement of RpoZ in regulation of some genes. Possible mechanisms of altered distribution of RNAP inside prophages are discussed. IMPORTANCE The 91-amino-acid-residue small-subunit omega (the rpoZ gene product) of Escherichia coli RNA polymerase plays a structural role in the formation of RNA polymerase (RNAP) as a chaperone in folding the largest subunit (β', of 1,407 residues in length), but except for binding of the stringent signal ppGpp, little is known of its role in the control of RNAP function. After analysis of genomewide distribution of wild-type and RpoZ-defective RNAP by the ChIP-chip method, we found alteration of the RpoZ-defective RNAP inside open reading frames, in particular, of the genes within prophages. For a set of the genes that exhibited altered occupancy of the RpoZ-defective RNAP, transcription was found to be altered as observed by qRT-PCR assay. All the observations here described indicate the involvement of RpoZ in recognition of some of the prophage genes. This study advances understanding of not only the regulatory role of omega subunit in the functions of RNAP but also the regulatory interplay between prophages and the host E. coli for adjustment of cellular physiology to a variety of environments in nature.
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Affiliation(s)
- Kaneyoshi Yamamoto
- Department of Frontier Bioscience, Hosei University, Tokyo, Japan
- Micro-Nano Technology Research Center, Hosei University, Tokyo, Japan
| | - Yuki Yamanaka
- Micro-Nano Technology Research Center, Hosei University, Tokyo, Japan
| | - Tomohiro Shimada
- Micro-Nano Technology Research Center, Hosei University, Tokyo, Japan
- Meiji University, School of Agriculture, Kawasaki, Kanagawa, Japan
| | - Paramita Sarkar
- Department of Frontier Bioscience, Hosei University, Tokyo, Japan
- Indian Institute of Science, Molecular Biophysics Unit, Bangalore, India
| | - Myu Yoshida
- Department of Frontier Bioscience, Hosei University, Tokyo, Japan
| | - Neerupma Bhardwaj
- Indian Institute of Science, Molecular Biophysics Unit, Bangalore, India
| | - Hiroki Watanabe
- Department of Frontier Bioscience, Hosei University, Tokyo, Japan
| | - Yuki Taira
- Department of Frontier Bioscience, Hosei University, Tokyo, Japan
| | - Dipankar Chatterji
- Indian Institute of Science, Molecular Biophysics Unit, Bangalore, India
| | - Akira Ishihama
- Micro-Nano Technology Research Center, Hosei University, Tokyo, Japan
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Single-gene deletion mutants of Escherichia coli with altered sensitivity to bicyclomycin, an inhibitor of transcription termination factor Rho. J Bacteriol 2011; 193:2229-35. [PMID: 21357484 DOI: 10.1128/jb.01463-10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have screened the entire KEIO collection of 3,985 single-gene knockouts in Escherichia coli for increased susceptibility or resistance to the antibiotic bicyclomycin (BCM), a potent inhibitor of the transcription termination factor Rho. We also compared the results to those of a recent study we conducted with a large set of antibiotics (A. Liu et al., Antimicrob. Agents Chemother. 54:1393-1403, 2010). We find that deletions of many different types of genes increase sensitivity to BCM. Some of these are involved in multidrug sensitivity/resistance, whereas others are specific for BCM. Mutations in a number of DNA recombination and repair genes increase BCM sensitivity, indicating that DNA damage leading to single- and double-strand breaks is a downstream effect of Rho inhibition. MDS42, which is deleted for all cryptic prophages and insertion elements (G. Posfai et al., Science 312:1044-1046, 2006), or W3102 deleted for the rac prophage-encoded kil gene, are partially resistant to BCM (C. J. Cardinale et al., Science 230:935-938, 2008). Deletion of cryptic prophages also overcomes the increased BCM sensitivity in some but not all mutants examined here. Deletion of the hns gene renders the cell more sensitive to BCM even in the Δkil or MDS42 background. This suggests that BCM activates additional modes of cell death independent of Kil and that these could provide a target to potentiate BCM killing.
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Abstract
Bacterial genome nucleotide sequences are being completed at a rapid and increasing rate. Integrated virus genomes (prophages) are common in such genomes. Fifty-one of the 82 such genomes published to date carry prophages, and these contain 230 recognizable putative prophages. Prophages can constitute as much as 10-20% of a bacterium's genome and are major contributors to differences between individuals within species. Many of these prophages appear to be defective and are in a state of mutational decay. Prophages, including defective ones, can contribute important biological properties to their bacterial hosts. Therefore, if we are to comprehend bacterial genomes fully, it is essential that we are able to recognize accurately and understand their prophages from nucleotide sequence analysis. Analysis of the evolution of prophages can shed light on the evolution of both bacteriophages and their hosts. Comparison of the Rac prophages in the sequenced genomes of three Escherichia coli strains and the Pnm prophages in two Neisseria meningitidis strains suggests that some prophages can lie in residence for very long times, perhaps millions of years, and that recombination events have occurred between related prophages that reside at different locations in a bacterium's genome. In addition, many genes in defective prophages remain functional, so a significant portion of the temperate bacteriophage gene pool resides in prophages.
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Affiliation(s)
- Sherwood Casjens
- Department of Pathology, University of Utah Medical School, Salt Lake City, UT 84132-2501, USA.
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Holčík M, Iyer VM. Conditionally lethal genes associated with bacterial plasmids. MICROBIOLOGY (READING, ENGLAND) 1997; 143 ( Pt 11):3403-3416. [PMID: 9387219 DOI: 10.1099/00221287-143-11-3403] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Martin Holčík
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa Ontario Canada K1S5B6
| | - V M Iyer
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa Ontario Canada K1S5B6
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Conter A, Bouché JP, Dassain M. Identification of a new inhibitor of essential division gene ftsZ as the kil gene of defective prophage Rac. J Bacteriol 1996; 178:5100-4. [PMID: 8752325 PMCID: PMC178304 DOI: 10.1128/jb.178.17.5100-5104.1996] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A gene function carried by a plasmid, causing arrest of cell division in Escherichia coli, has been identified as the product of a short open reading frame of the prophage Rac, previously designated orfE, expressed only under conditions of prophage induction. Because Rac carries a killing function expressed under conditions of zygotic induction, an orfE-defective Rac+ strain was constructed. This strain had lost the killing function, indicating that orfE is kil. Division inhibition by kil was specifically relieved by overexpression of essential division gene ftsZ. The kil gene product acts independently of the min operon, and its effects are increased in conditions of high cyclic AMP (cAMP) receptor protein-cAMP complex levels in the cell. Furthermore, at high levels of expression, kil product distorts the rod shape of the cells. These features distinguish kil-encoded protein from the inhibitory product of gene dicB, which occupies a similar genetic location in Kim (Qin), another defective prophage of Escherichia coli.
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Affiliation(s)
- A Conter
- Laboratoire de Microbiologie et de Genetique Moleculaire du Centre National de la Recherche Scientifique, Toulouse, France
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Misra R, Benson SA. A novel mutation, cog, which results in production of a new porin protein (OmpG) of Escherichia coli K-12. J Bacteriol 1989; 171:4105-11. [PMID: 2473977 PMCID: PMC210179 DOI: 10.1128/jb.171.8.4105-4111.1989] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A mutant of Escherichia coli K-12 which produces a new outer membrane protein, OmpG, was isolated and genetically and biochemically characterized. The presence of OmpG allows growth on maltodextrins in the absence of the LamB maltoporin. The data obtained from in vivo growth and uptake experiments suggested that the presence of the OmpG protein results in an increase in outer membrane permeability for small hydrophilic compounds. In light of these findings, we suggest that OmpG is a porinlike protein. The mutation which results in the expression of OmpG has been termed cog (for control of OmpG) and mapped to 29 min on the E. coli chromosome. Diploid analysis shows that the mutant cog-192 allele is recessive for both the Dex+ and OmpG+ phenotypes. We propose that the cog mutation destroys a negative regulatory function and therefore derepresses ompG expression.
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Affiliation(s)
- R Misra
- Department of Biology, Princeton University, New Jersey 08544-1014
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Béjar S, Bouché F, Bouché JP. Cell division inhibition gene dicB is regulated by a locus similar to lambdoid bacteriophage immunity loci. MOLECULAR & GENERAL GENETICS : MGG 1988; 212:11-9. [PMID: 2836697 DOI: 10.1007/bf00322439] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A mutation (dicA1) of a repressor gene located in the terminus region of the Escherichia coli chromosome has previously been shown to lead to temperature-dependent inhibition of division, and to be complemented by plasmids carrying either dicA or an adjacent gene dicC. In this study, operon fusions in the region coding for the division inhibition gene dicB have been used to show that temperature sensitivity does not result from high temperature inactivation of the dicA repressor. Sequence comparisons indicate that dicA and dicC are similar to genes c2 and cro respectively of bacteriophage P22, and carry similarly organized tandem operators, indicating a common evolutionary origin for dicAC and P22 immC. Nevertheless, the consensus half-operator sequence of dicAC, TGTTA-GYYA, differs significantly from that of P22 immC (ATT-TAAGAN). An analysis of the in vivo control of promoters dicAp, dicBp and dicCp placed upstream of malQ shows that the dicAC system is functionally similar to that of an immunity region, with the possible exception of an absence of pairwise cooperative binding. Our results also indicate that the dicA1 mutation causes a switch to permanent control by dicC at all temperatures.
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Affiliation(s)
- S Béjar
- Centre de Recherches de Biochimie et de Génétique Cellulaires du CNRS, Toulouse, France
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D'Ari R, Huisman O. Novel mechanism of cell division inhibition associated with the SOS response in Escherichia coli. J Bacteriol 1983; 156:243-50. [PMID: 6352679 PMCID: PMC215076 DOI: 10.1128/jb.156.1.243-250.1983] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Certain Escherichia coli strains were shown to possess a novel system of cell division inhibition, called the SfiC+ phenotype. SfiC+ filamentation had a number of properties similar to those of sfiA-dependent division inhibition previously described: (i) both are associated with the SOS response induced by expression of the recA(Tif) mutation, (ii) both are associated with cell death, (iii) both are amplified in mutants lacking the Lon protease, and (iv) both are suppressed by sfiB mutations. SfiC+ filamentation and sfiA-dependent division inhibition differed in (i) the physiological conditions under which loss of viability is observed, (ii) the extent of amplification in lon mutants, (iii) their genetic regulation (SfiC+ filamentation is not under direct negative control of the LexA repressor), and (iv) their genetic determinants (SfiC+ filamentation depends on a locus, sfiC+, near 28 min on the E. coli map and distinct from sfiA).
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