uu.seUppsala University Publications
Change search
Refine search result
1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Bergman, Jessica
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Hammarlöf, Disa L
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Hughes, Diarmaid
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Reducing ppGpp Level Rescues an Extreme Growth Defect Caused by Mutant EF-Tu2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 2, p. e90486-Article in journal (Other academic)
    Abstract [en]

    Salmonella enterica grows extremely slowly when it depends on tufA499 (encoding the Gln125Arg mutant form of EF-Tu) to drive protein synthesis. We screened a plasmid library for multi-copy suppressors of the slow growth phenotype and identified spoT as a candidate. The spoT gene encodes a dual function enzyme with both ppGpp synthetase and hydrolase activities. When spoT was cloned behind an arabinose-inducible promoter the growth rate of the mutant strain increased in response to arabinose addition. We found that the slow-growing mutant strain had a relatively high basal level of ppGpp during exponential growth in rich medium. Overexpression of spoT significantly reduced this level of ppGpp suggesting that inappropriately high ppGpp levels might cause the slow growth rate associated with tufA499. We tested this hypothesis by inactivating relA (codes for RelA, a ribosome-associated ppGpp synthetase) in the mutant strain. This inactivation decreased the level of ppGpp in the mutant strain and increased its growth rate. Based on these data we propose that ribosomes depending on tufA499 for their supply of ternary complex (EF-Tu•GTP•aa-tRNA) experience amino acid starvation and that RelA on these starving ribosomes produces an excess of the alarmone ppGpp. This results in a suboptimal partitioning of transcription activity between genes important for fast growth in rich medium and genes important for growth in a poor medium. Accordingly, mutant bacteria growing in a rich medium act physiologically as though they were growing in a nutrient-poor environment. We propose that this generates a vicious circle and contributes to the extreme slow-growth phenotype associated with mutant EF-Tu. Reducing the level of ppGpp increases the growth rate of the mutant because it breaks this circle and reduces the wasteful misdirection of resources in the cell.

  • 2.
    Bergman, Jessica M.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Genetics and Growth Regulation in Salmonella enterica2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Most free-living bacteria will encounter different environments and it is therefore critical to be able to rapidly adjust to new growth conditions in order to be competitively successful. Responding to changes requires efficient gene regulation in terms of transcription, RNA stability, translation and post-translational modifications.

    Studies of an extremely slow-growing mutant of Salmonella enterica, with a Glu125Arg mutant version of EF-Tu, revealed it to be trapped in a stringent response. The perceived starvation was demonstrated to be the result of increased mRNA cleavage of aminoacyl-tRNA synthetase genes leading to lower prolyl-tRNA levels. The mutant EF-Tu caused an uncoupling of transcription and translation, leading to increased turnover of mRNA, which trapped the mutant in a futile stringent response.

    To examine the essentiality of RNase E, we selected and mapped three classes of extragenic suppressors of a ts RNase E phenotype. The ts RNase E mutants were defective in the degradation of mRNA and in the processing of tRNA and rRNA. Only the degradation of mRNA was suppressed by the compensatory mutations. We therefore suggest that degradation of at least a subset of cellular mRNAs is an essential function of RNase E.

    Bioinformatically, we discovered that the mRNA of tufB, one of the two genes encoding EF-Tu, could form a stable structure masking the ribosomal binding site. This, together with previous studies that suggested that the level of EF-Tu protein could affect the expression of tufB, led us to propose three models for how this could occur. The stability of the tufB RNA structure could be affected by the elongation rate of tufB-translating ribosomes, possibly influenced by the presence of rare codons early in the in tufB mRNA.

    Using proteomic and genetic assays we concluded that two previously isolated RNAP mutants, each with a growth advantage when present as subpopulations on aging wild-type colonies, were dependent on the utilization of acetate for this phenotype. Increased growth of a subpopulation of wild-type cells on a colony unable to re-assimilate acetate demonstrated that in aging colonies, acetate is available in levels sufficient to sustain the growth of at least a small subpopulation of bacteria. 

    List of papers
    1. Reducing ppGpp Level Rescues an Extreme Growth Defect Caused by Mutant EF-Tu
    Open this publication in new window or tab >>Reducing ppGpp Level Rescues an Extreme Growth Defect Caused by Mutant EF-Tu
    2014 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 2, p. e90486-Article in journal (Other academic) Published
    Abstract [en]

    Salmonella enterica grows extremely slowly when it depends on tufA499 (encoding the Gln125Arg mutant form of EF-Tu) to drive protein synthesis. We screened a plasmid library for multi-copy suppressors of the slow growth phenotype and identified spoT as a candidate. The spoT gene encodes a dual function enzyme with both ppGpp synthetase and hydrolase activities. When spoT was cloned behind an arabinose-inducible promoter the growth rate of the mutant strain increased in response to arabinose addition. We found that the slow-growing mutant strain had a relatively high basal level of ppGpp during exponential growth in rich medium. Overexpression of spoT significantly reduced this level of ppGpp suggesting that inappropriately high ppGpp levels might cause the slow growth rate associated with tufA499. We tested this hypothesis by inactivating relA (codes for RelA, a ribosome-associated ppGpp synthetase) in the mutant strain. This inactivation decreased the level of ppGpp in the mutant strain and increased its growth rate. Based on these data we propose that ribosomes depending on tufA499 for their supply of ternary complex (EF-Tu•GTP•aa-tRNA) experience amino acid starvation and that RelA on these starving ribosomes produces an excess of the alarmone ppGpp. This results in a suboptimal partitioning of transcription activity between genes important for fast growth in rich medium and genes important for growth in a poor medium. Accordingly, mutant bacteria growing in a rich medium act physiologically as though they were growing in a nutrient-poor environment. We propose that this generates a vicious circle and contributes to the extreme slow-growth phenotype associated with mutant EF-Tu. Reducing the level of ppGpp increases the growth rate of the mutant because it breaks this circle and reduces the wasteful misdirection of resources in the cell.

    Keywords
    tufA; ppGpp; RelA; Salmonella enterica; growth regulation
    National Category
    Microbiology
    Research subject
    Microbiology; Molecular Cellbiology
    Identifiers
    urn:nbn:se:uu:diva-159663 (URN)10.1371/journal.pone.0090486 (DOI)000332396200210 ()
    Note

    Jessica M. Bergman and Disa L. Hammarlöf contributed equally to this work.

    Available from: 2011-10-06 Created: 2011-10-05 Last updated: 2017-12-08Bibliographically approved
    2. Turnover of mRNAs is an essential function of RNase E
    Open this publication in new window or tab >>Turnover of mRNAs is an essential function of RNase E
    (English)Manuscript (preprint) (Other academic)
    Keywords
    rpsA, vacB, RNaseR, RelBE, RNA turnover
    National Category
    Microbiology in the medical area
    Research subject
    Biology with specialization in Microbiology; Microbiology; Molecular Genetics
    Identifiers
    urn:nbn:se:uu:diva-235199 (URN)
    Available from: 2014-10-29 Created: 2014-10-29 Last updated: 2018-01-11
    3. Autoregulation of the tufB operon in Salmonella
    Open this publication in new window or tab >>Autoregulation of the tufB operon in Salmonella
    2016 (English)In: Molecular Microbiology, ISSN 0950-382X, E-ISSN 1365-2958, Vol. 100, no 6, p. 1004-1016Article in journal (Refereed) Published
    Abstract [en]

    In Salmonella enterica and related species, translation elongation factor EF-Tu is encoded by two widely separated but near-identical genes, tufA and tufB. Two thirds of EF-Tu is expressed from tufA with the remaining one third coming from tufB. Inactivation of tufA is partly compensated by a doubling in the amount of EF-TuB but the mechanism of this up-regulation is unknown. By experimental evolution selecting for improved growth rate in a strain with an inactive tufA we selected six different noncoding or synonymous point mutations close to the tufB start codon. Based on these results we constructed a total of 161 different point mutations around the tufB start codon, as well as tufB 3'-truncations, and measured tufB expression using tufB-yfp transcriptional and translational fusions. The expression data support the presence of two competing stem-loop structures that can form in the 5'-end of the tufB mRNA. Formation of the 'closed' structure leads to Rho-dependent transcriptional termination of the tufB mRNA. We propose a model in which translational speed is used as a sensor for EF-Tu concentration and where the expression of tufB is post-transcriptionally regulated. This model describes for the first time how expression of the most abundant Salmonella protein is autoregulated.

    Keywords
    Salmonella enterica, tufA, tufB, EF-Tu, Rho, post-transcriptional regulation
    National Category
    Microbiology in the medical area
    Research subject
    Biology with specialization in Microbiology; Microbiology; Molecular Genetics
    Identifiers
    urn:nbn:se:uu:diva-235218 (URN)10.1111/mmi.13364 (DOI)000379687100008 ()26934594 (PubMedID)
    Funder
    Knut and Alice Wallenberg Foundation, KAW 2009.0251Swedish Research Council, 621-2012-2188; 521-2013-2904
    Available from: 2014-10-29 Created: 2014-10-29 Last updated: 2018-01-11Bibliographically approved
    4. Acetate availability and utilization supports the growth of mutant sub-populations on aging bacterial colonies
    Open this publication in new window or tab >>Acetate availability and utilization supports the growth of mutant sub-populations on aging bacterial colonies
    2014 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 10, p. e109255-Article in journal (Refereed) Published
    Abstract [en]

    When bacterial colonies age most cells enter a stationary phase, but sub-populations of mutant bacteria can continue to grow and accumulate. These sub-populations include bacteria with mutations in rpoB (RNA polymerase β-subunit) or rpoS (RNA polymerase stress-response sigma factor). Here we have identified acetate as a nutrient present in the aging colonies that is utilized by these mutant subpopulations to support their continued growth. Proteome analysis of aging colonies showed that several proteins involved in acetate conversion and utilization were upregulated during aging. Acetate is known to be excreted during the exponential growth phase but can be imported later during the transition to stationary phase and converted to acetyl-CoA. Acetyl-CoA is used in multiple processes, including feeding into the TCA cycle, generating ATP via the glyoxylate shunt, as a source of acetyl groups for protein modification, and to support fatty acid biosynthesis. We showed that deletion of acs (encodes acetyl-CoA synthetase; converts acetate into acetyl-CoA) significantly reduced the accumulation of rpoB and rpoS mutant subpopulations on aging colonies. Measurement of radioactive acetate uptake showed that the rate of conversion decreased in aging wild-type colonies, was maintained at a constant level in the rpoB mutant, and significantly increased in the aging rpoS mutant. Finally, we showed that the growth of subpopulations on aging colonies was greatly enhanced if the aging colony itself was unable to utilize acetate, leaving more acetate available for mutant subpopulations to use. Accordingly, the data show that the accumulation of subpopulations of rpoB and rpoS mutants on aging colonies is supported by the availability in the aging colony of acetate, and by the ability of the subpopulation cells to convert the acetate to acetyl-CoA.

    Keywords
    aceBAK, ackA-pta, acs, pka, growth in stationary phase, Salmonella Typhimurium
    National Category
    Microbiology in the medical area
    Research subject
    Microbiology
    Identifiers
    urn:nbn:se:uu:diva-234281 (URN)10.1371/journal.pone.0109255 (DOI)000342591500086 ()25275605 (PubMedID)
    Available from: 2014-10-15 Created: 2014-10-15 Last updated: 2018-01-11Bibliographically approved
  • 3.
    Bergman, Jessica M
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Wrande, Marie
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America.
    Hughes, Diarmaid
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Acetate availability and utilization supports the growth of mutant sub-populations on aging bacterial colonies2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 10, p. e109255-Article in journal (Refereed)
    Abstract [en]

    When bacterial colonies age most cells enter a stationary phase, but sub-populations of mutant bacteria can continue to grow and accumulate. These sub-populations include bacteria with mutations in rpoB (RNA polymerase β-subunit) or rpoS (RNA polymerase stress-response sigma factor). Here we have identified acetate as a nutrient present in the aging colonies that is utilized by these mutant subpopulations to support their continued growth. Proteome analysis of aging colonies showed that several proteins involved in acetate conversion and utilization were upregulated during aging. Acetate is known to be excreted during the exponential growth phase but can be imported later during the transition to stationary phase and converted to acetyl-CoA. Acetyl-CoA is used in multiple processes, including feeding into the TCA cycle, generating ATP via the glyoxylate shunt, as a source of acetyl groups for protein modification, and to support fatty acid biosynthesis. We showed that deletion of acs (encodes acetyl-CoA synthetase; converts acetate into acetyl-CoA) significantly reduced the accumulation of rpoB and rpoS mutant subpopulations on aging colonies. Measurement of radioactive acetate uptake showed that the rate of conversion decreased in aging wild-type colonies, was maintained at a constant level in the rpoB mutant, and significantly increased in the aging rpoS mutant. Finally, we showed that the growth of subpopulations on aging colonies was greatly enhanced if the aging colony itself was unable to utilize acetate, leaving more acetate available for mutant subpopulations to use. Accordingly, the data show that the accumulation of subpopulations of rpoB and rpoS mutants on aging colonies is supported by the availability in the aging colony of acetate, and by the ability of the subpopulation cells to convert the acetate to acetyl-CoA.

  • 4.
    Brandis, Gerrit
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Bergman, Jessica M.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Hughes, Diarmaid
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Autoregulation of the tufB operon in Salmonella2016In: Molecular Microbiology, ISSN 0950-382X, E-ISSN 1365-2958, Vol. 100, no 6, p. 1004-1016Article in journal (Refereed)
    Abstract [en]

    In Salmonella enterica and related species, translation elongation factor EF-Tu is encoded by two widely separated but near-identical genes, tufA and tufB. Two thirds of EF-Tu is expressed from tufA with the remaining one third coming from tufB. Inactivation of tufA is partly compensated by a doubling in the amount of EF-TuB but the mechanism of this up-regulation is unknown. By experimental evolution selecting for improved growth rate in a strain with an inactive tufA we selected six different noncoding or synonymous point mutations close to the tufB start codon. Based on these results we constructed a total of 161 different point mutations around the tufB start codon, as well as tufB 3'-truncations, and measured tufB expression using tufB-yfp transcriptional and translational fusions. The expression data support the presence of two competing stem-loop structures that can form in the 5'-end of the tufB mRNA. Formation of the 'closed' structure leads to Rho-dependent transcriptional termination of the tufB mRNA. We propose a model in which translational speed is used as a sensor for EF-Tu concentration and where the expression of tufB is post-transcriptionally regulated. This model describes for the first time how expression of the most abundant Salmonella protein is autoregulated.

  • 5. Fuchino, Katsuya
    et al.
    Bagchi, Sonchita
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Cantlay, Stuart
    Sandblad, Linda
    Wu, Di
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular tools. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Bergman, Jessica
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Kamali-Moghaddam, Masood
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular tools. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Flärdh, Klas
    Ausmees, Nora
    Dynamic gradients of an intermediate filament-like cytoskeleton are recruited by a polarity landmark during apical growth2013In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 110, no 21, p. E1889-E1897Article in journal (Refereed)
    Abstract [en]

    Intermediate filament (IF)-like cytoskeleton emerges as a versatile tool for cellular organization in all kingdoms of life, underscoring the importance of mechanistically understanding its diverse manifestations. We showed previously that, in Streptomyces (a bacterium with a mycelial lifestyle similar to that of filamentous fungi, including extreme cell and growth polarity), the IF protein FilP confers rigidity to the hyphae by an unknown mechanism. Here, we provide a possible explanation for the IF-like function of FilP by demonstrating its ability to self-assemble into a cis-interconnected regular network in vitro and its localization into structures consistent with a cytoskeletal network in vivo. Furthermore, we reveal that a spatially restricted interaction between FilP and DivIVA, the main component of the Streptomyces polarisome complex, leads to formation of apical gradients of FilP in hyphae undergoing active tip extension. We propose that the coupling between the mechanism driving polar growth and the assembly of an IF cytoskeleton provides each new hypha with an additional stress-bearing structure at its tip, where the nascent cell wall is inevitably more flexible and compliant while it is being assembled and matured. Our data suggest that recruitment of cytoskeleton around a cell polarity landmark is a broadly conserved strategy in tip-growing cells.

  • 6.
    Gao, Tianle
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience. Chinese Acad Med Sci, Inst Mat Med, Beijing, Peoples R China.
    Ma, Haisha
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Developmental Genetics.
    Xu, Bo
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Bergman, Jessica
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Larhammar, Dan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Pharmacology.
    Lagerström, Malin C.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Developmental Genetics.
    The Neuropeptide Y System Regulates Both Mechanical and Histaminergic Itch2018In: Journal of Investigative Dermatology, ISSN 0022-202X, E-ISSN 1523-1747, Vol. 138, no 11, p. 2405-2411Article in journal (Refereed)
    Abstract [en]

    Itch is a somatosensory modality that serves to alert an organism to harmful elements removable by scratching, such as parasites and chemical irritants. Recently, ablation or silencing of neuropeptide Y (NPY)-expressing spinal interneurons was reported to selectively enhance mechanical itch, whereas chemical itch was unaffected. We examined the effect of activating the NPY/Y-1 receptor system on scratch behavior in mice. We found that intrathecal administration of the Y-1 agonist [Leu(31), Pro(34)]-NPY (LP-NPY) attenuated itch behavior induced by application of 0.07 g von Frey filament in the nape of the neck compared with saline treatment, indicating that activation of the spinal NPY/Y-1 system dampens mechanical itch. However, intrathecal administration of LP-NPY also attenuated chemically induced scratching provoked by intradermal application of histamine or the mast cell degranulator 48/80 (histaminergic itch), and the latter effect could be reversed by administration of the Y-1 antagonist BIBO3304. Intrathecal application of the native nonselective agonist NPY also attenuated histamine or 48/80-induced scratching. Our analyses emphasize the importance of including additional quantitative parameters to characterize the full spectrum of itch behavior and show that the NPY/Y-1 system dampens both mechanically and chemically induced scratching and hence is shared by the two submodalities of itch.

  • 7.
    Hammarlöf, Disa L.
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Karolinska Institutet, Solna, Sweden.
    Bergman, Jessica M
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Garmendia, Eva
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Hughes, Diarmaid
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Turnover of mRNAs is an essential function of RNase EManuscript (preprint) (Other academic)
  • 8.
    Larsson Hammarlöf, Disa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Bergman, Jessica M.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Garmendia, Eva
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Hughes, Diarmaid
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Turnover of mRNAs is one of the essential functions of RNase E2015In: Molecular Microbiology, ISSN 0950-382X, E-ISSN 1365-2958, Vol. 98, no 1, p. 34-45Article in journal (Refereed)
    Abstract [en]

    RNase E is an essential bacterial endoribonuclease with a central role in processing tRNAs and rRNA, and turning over mRNAs. Previous studies in strains carrying mutations in the rne structural gene have shown that tRNA processing is likely to be an essential function of RNase E but have not determined whether mRNA turnover is also an essential function. To address this we selected extragenic suppressors of temperature-sensitive mutations in rne that cause a large increase in mRNA half-life at the non-permissive temperature. Fifteen suppressors were mapped to three different loci: relBE (toxin-antitoxin system); vacB (RNase R); and rpsA (ribosomal protein S1). Each suppressor class has the potential to interact with mRNA and each restores wild-type levels of mRNA turnover but does not reverse the minor defects in tRNA and rRNA processing. RelE toxin is especially interesting because its only known activity is to cleave mRNAs in the ribosomal A-site. The relBE suppressor mutations increase transcription of relE, and controlled overexpression of RelE alone was sufficient to suppress the rne ts phenotype. Suppression increased turnover of some major mRNAs (tufA, ompA) but not all mRNAs. We propose that turnover of some mRNAs is one of the essential functions of RNase E.

1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf