Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Sciences (General)
Type of Medium
Language
Year
  • 1
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 21 April 2015, Vol.112(16), pp.5159-64
    Description: RpoS, the stationary phase/stress sigma factor of Escherichia coli, regulates a large cohort of genes important for the cell to deal with suboptimal conditions. Its level increases quickly in the cell in response to many stresses and returns to low levels when growth resumes. Increased RpoS results from increased translation and decreased RpoS degradation. Translation is positively regulated by small RNAs (sRNAs). Protein stability is positively regulated by anti-adaptors, which prevent the RssB adaptor-mediated degradation of RpoS by the ClpXP protease. Inactivation of aceE, a subunit of pyruvate dehydrogenase (PDH), was found to increase levels of RpoS by affecting both translation and protein degradation. The stabilization of RpoS in aceE mutants is dependent on increased transcription and translation of IraP and IraD, two known anti-adaptors. The aceE mutation also leads to a significant increase in rpoS translation. The sRNAs known to positively regulate RpoS are not responsible for the increased translation; sequences around the start codon are sufficient for the induction of translation. PDH synthesizes acetyl-CoA; acetate supplementation allows the cell to synthesize acetyl-CoA by an alternative, less favored pathway, in part dependent upon RpoS. Acetate addition suppressed the effects of the aceE mutant on induction of the anti-adaptors, RpoS stabilization, and rpoS translation. Thus, the bacterial cell responds to lowered levels of acetyl-CoA by inducing RpoS, allowing reprogramming of E. coli metabolism.
    Keywords: Clpxp ; Rpos ; Rssb ; Acetyl Coa ; Pyruvate Dehydrogenase ; Protein Biosynthesis ; Proteolysis ; Stress, Physiological ; Bacterial Proteins -- Metabolism ; Escherichia Coli -- Metabolism ; Sigma Factor -- Metabolism
    ISSN: 00278424
    E-ISSN: 1091-6490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: Science, 27 July 2001, Vol.293(5530), pp.614-615
    Keywords: Physical sciences -- Chemistry -- Chemical compounds -- Ribonucleoproteins ; Physical sciences -- Chemistry -- Chemical compounds -- Ribonucleoproteins ; Biological sciences -- Biology -- Cytology -- Ribonucleoproteins ; Health sciences -- Medical sciences -- Nutritional science -- Ribonucleoproteins ; Physical sciences -- Chemistry -- Chemical compounds -- Ribonucleoproteins ; Physical sciences -- Chemistry -- Chemical compounds -- Ribonucleoproteins ; Biological sciences -- Biology -- Cytology -- Ribonucleoproteins ; Biological sciences -- Biology -- Cytology -- Ribonucleoproteins ; Physical sciences -- Physics -- Microphysics -- Ribonucleoproteins ; Biological sciences -- Biochemistry -- Metabolism -- Ribonucleoproteins
    ISSN: 00368075
    E-ISSN: 10959203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 3 May 2011, Vol.108(18), pp.7403-7407
    Description: Eukaryotic PIN (PilT N-terminal) domain proteins are ribonucleases involved in quality control, metabolism and maturation of mRNA and rRNA. The majority of prokaryotic PIN-domain proteins are encoded by the abundant vapBC toxin—antitoxin loci and inhibit translation by an unknown mechanism. Here we show that enteric VapCs are site-specific endonucleases that cleave tRNAfMet in the anticodon stem-loop between nucleotides +38 and +39 in vivo and in vitro. Consistently, VapC inhibited translation in vivo and in vitro. Translation-reactions could be reactivated by the addition of VapB and extra charged tRNA fMet . Similarly, ectopic production of tRNAfMet counteracted VapC in vivo. Thus, tRNAfMet is the only cellular target of VapC. Depletion of tRNAfMet by vapC induction was bacteriostatic and stimulated ectopic translation initiation at elongator codons. Moreover, addition of chloramphenicol to cells carrying vapBC induced VapC activity. Thus, by cleavage of tRNAfMet , VapC simultaneously may regulate global cellular translation and reprogram translation initiation.
    Keywords: Physical sciences -- Chemistry -- Chemical compounds -- Antitoxins ; Physical sciences -- Chemistry -- Chemical compounds -- Antitoxins ; Biological sciences -- Biology -- Genetics -- Antitoxins ; Biological sciences -- Biochemistry -- Biomolecules -- Antitoxins ; Physical sciences -- Chemistry -- Chemical compounds -- Antitoxins ; Biological sciences -- Biology -- Genetics -- Antitoxins ; Biological sciences -- Biology -- Genetics -- Antitoxins ; Biological sciences -- Biology -- Cytology -- Antitoxins ; Health sciences -- Medical sciences -- Immunology -- Antitoxins ; Biological sciences -- Biology -- Genetics -- Antitoxins
    ISSN: 00278424
    E-ISSN: 10916490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 25 May 2010, Vol.107(21), pp.9602-7
    Description: Bacterial small noncoding RNAs carry out both positive and negative regulation of gene expression by pairing with mRNAs; in Escherichia coli, this regulation often requires the RNA chaperone Hfq. Three small regulatory RNAs (sRNAs), DsrA, RprA, and ArcZ, positively regulate translation of the sigma factor RpoS, each pairing with the 5' leader to open up an inhibitory hairpin. In vitro, rpoS interaction with sRNAs depends upon an (AAN)(4) Hfq-binding site upstream of the pairing region. Here we show that both Hfq and this Hfq binding site are required for RprA or ArcZ to act in vivo and to form a stable complex with rpoS mRNA in vitro; both were partially dispensable for DsrA at 37 degrees C. ArcZ sRNA is processed from 121 nt to a stable 56 nt species that contains the pairing region; only the 56 nt ArcZ makes a strong Hfq-dependent complex with rpoS. For each of these sRNAs, the stability of the sRNA*mRNA complexes, rather than their rate of formation, best predicted in vivo activity. These studies demonstrate that binding of Hfq to the rpoS mRNA is critical for sRNA regulation under normal conditions, but if the stability of the sRNA*mRNA complex is sufficiently high, the requirement for Hfq can be bypassed.
    Keywords: Escherichia Coli -- Metabolism ; Host Factor 1 Protein -- Metabolism ; RNA, Bacterial -- Metabolism ; RNA, Untranslated -- Metabolism
    ISSN: 00278424
    E-ISSN: 1091-6490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 11 October 2016, Vol.113(41), pp.E6089-E6096
    Description: The bacterial Sm protein and RNA chaperone Hfq stabilizes small noncoding RNAs (sRNAs) and facilitates their annealing to mRNA targets involved in stress tolerance and virulence. Although an arginine patch on the Sm core is needed for Hfq's RNA chaperone activity, the function of Hfq's intrinsically disordered C-terminal domain (CTD) has remained unclear. Here, we use stopped flow spectroscopy to show that the CTD of Escherichia coli Hfq is not needed to accelerate RNA base pairing but is required for the release of dsRNA. The Hfq CTD also mediates competition between sRNAs, offering a kinetic advantage to sRNAs that contact both the proximal and distal faces of the Hfq hexamer. The change in sRNA hierarchy caused by deletion of the Hfq CTD in E. coli alters the sRNA accumulation and the kinetics of sRNA regulation in vivo. We propose that the Hfq CTD displaces sRNAs and annealed sRNA⋅mRNA complexes from the Sm core, enabling Hfq to chaperone sRNA-mRNA interactions and rapidly cycle between competing targets in the cell.
    Keywords: Chix ; RNA Chaperone ; Intrinsically Disordered Protein ; Posttranscriptional Regulation ; Small Noncoding RNA ; Protein Interaction Domains and Motifs ; Host Factor 1 Protein -- Chemistry ; RNA, Messenger -- Metabolism ; RNA, Small Untranslated -- Metabolism
    ISSN: 00278424
    E-ISSN: 1091-6490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 22 June 2010, Vol.107(25), pp.11543-11548
    Description: To monitor inaccuracy in gene expression in living cells, we designed an experimental system in the bacterium Bacillus subtilis whereby spontaneous errors can be visualized and quantified at a single-cell level. Our strategy was to introduce mutations into a chromosomally encoded gfp allele, such that errors in protein production are reported in real time by the formation of fluorescent GFP molecules. The data reveal that the amount of errors can greatly exceed previous estimates, and that the amount of error rate increases dramatically at lower temperatures and during stationary phase. Furthermore, we demonstrate that when facing an antibiotic threat, an increase in error level is sufficient to allow survival of bacteria carrying a mutated antibiotic-resistance gene. We propose that bacterial gene expression is error prone, frequently yielding protein molecules that differ slightly from the sequence specified by their DNA, thus generating a cellular reservoir of nonidentical protein molecules. This variation may be a key factor in increasing bacterial fitness, expanding the capability of an isogenic population to face environmental challenges.
    Keywords: Physical sciences -- Physics -- Fundamental forces ; Biological sciences -- Biology -- Genetics ; Biological sciences -- Biology -- Genetics ; Physical sciences -- Physics -- Microphysics ; Mathematics -- Mathematical procedures -- Approximation ; Mathematics -- Applied mathematics -- Statistics ; Biological sciences -- Biology -- Microbiology ; Physical sciences -- Chemistry -- Chemical compounds ; Physical sciences -- Chemistry -- Chemical compounds ; Biological sciences -- Biology -- Genetics
    ISSN: 00278424
    E-ISSN: 10916490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 8 June 2010, Vol.107(23), pp.10691-10695
    Description: Perception and response to nutritional iron availability by bacteria are essential to control cellular iron homeostasis. The Irr protein from Bradyrhizobium japonicum senses iron through the status of heme biosynthesis to globally regulate iron-dependent gene expression. Heme binds directly to Irr to trigger its degradation. Here, we show that severe manganese limitation created by growth of a Mn²⁺ transport mutant in manganese-limited media resulted in a cellular iron deficiency. In wild-type cells, Irr levels were attenuated under manganese limitation, resulting in reduced promoter occupancy of target genes and altered iron-dependent gene expression. Irr levels were high regardless of manganese availability in a heme-deficient mutant, indicating that manganese normally affects heme-dependent degradation of Irr. Manganese altered the secondary structure of Irr in vitro and inhibited binding of heme to the protein. We propose that manganese limitation destabilizes Irr under low-iron conditions by lowering the threshold of heme that can trigger Irr degradation. The findings implicate a mechanism for the control of iron homeostasis by manganese in a bacterium.
    Keywords: Physical sciences -- Chemistry -- Chemical elements ; Physical sciences -- Chemistry -- Chemical elements ; Biological sciences -- Biology -- Genetics ; Physical sciences -- Chemistry -- Chemical compounds ; Biological sciences -- Biology -- Genetics ; Biological sciences -- Biology -- Microbiology ; Biological sciences -- Biology -- Cytology ; Biological sciences -- Biology -- Physiology ; Biological sciences -- Biochemistry -- Metabolism ; Biological sciences -- Biology -- Physiology
    ISSN: 00278424
    E-ISSN: 10916490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 17 March 1998, Vol.95(6), pp.2731-2732
    Description: In the unending wars of organism vs. organism, the growth of bacteriophage and the defenses raised by bacteria were among the first recognized and continue to provide new variations and insights on ways to defend oneself. A paper in this issue of the Proceedings demonstrates that prokaryotes, like eukaryotes, have chosen proteolytic self-destruction as a route to protection from attack, albeit a protection for the community rather than for the cell under attack (1).
    Keywords: Biological sciences -- Biology -- Microbiology -- Ribonucleoproteins ; Biological sciences -- Biochemistry -- Biomolecules -- Ribonucleoproteins ; Physical sciences -- Chemistry -- Chemical compounds -- Ribonucleoproteins ; Biological sciences -- Biology -- Cytology -- Ribonucleoproteins ; Biological sciences -- Biology -- Genetics -- Ribonucleoproteins ; Biological sciences -- Biology -- Genetics -- Ribonucleoproteins ; Biological sciences -- Biology -- Cytology -- Ribonucleoproteins ; Biological sciences -- Biology -- Biological taxonomies -- Ribonucleoproteins ; Health sciences -- Medical conditions -- Infections -- Ribonucleoproteins ; Health sciences -- Medical sciences -- Pharmaceutics -- Ribonucleoproteins
    ISSN: 00278424
    E-ISSN: 10916490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 20 April 2010, Vol.107(16), pp.7533-7538
    Description: Legionella pneumophila is a Gram-negative opportunistic human pathogen that infects and multiplies in a broad range of phagocytic protozoan and mammalian phagocytes. Based on the observation that small regulatory RNAs (sRNAs) play an important role in controlling virulence-related genes in several pathogenic bacteria, we attempted to identify sRNAs expressed by L. pneumophila. We used computational prediction followed by experimental verification to identify and characterize sRNAs encoded in the L. pneumophila genome. A 50-mer probe microarray was constructed to test the expression of predicted sRNAs in bacteria grown under a variety of conditions. This strategy successfully identified 22 expressed RNAs, out of which 6 were confirmed by northern blot and RACE. One of the identified sRNAs is highly expressed in postexponential phase, and computational prediction of its secondary structure reveals a striking similarity to the structure of 6S RNA, a widely distributed prokaryotic sRNA, known to regulate the activity of σ⁷⁰-containing RNA polymerase. A 70-mer probe microarray was used to identify genes affected by L. pneumophila 6S RNA in stationary phase. The 6S RNA positively regulates expression of genes encoding type IVB secretion system effectors, stress response genes such as groES and recA, as well as many genes involved in acquisition of nutrients and genes with unknown or hypothetical functions. Deletion of 6S RNA significantly reduced L. pneumophila intracellular multiplication in both protist and mammalian host cells, but had no detectable effect on growth in rich media.
    Keywords: Physical sciences -- Chemistry -- Chemical compounds -- Legionella pneumophila ; Biological sciences -- Biology -- Microbiology -- Legionella pneumophila ; Biological sciences -- Biology -- Genetics -- Legionella pneumophila ; Biological sciences -- Biology -- Genetics -- Legionella pneumophila ; Biological sciences -- Biology -- Cytology -- Legionella pneumophila ; Biological sciences -- Biology -- Microbiology -- Legionella pneumophila ; Biological sciences -- Biology -- Microbiology -- Legionella pneumophila ; Biological sciences -- Biology -- Genetics -- Legionella pneumophila ; Biological sciences -- Biology -- Genetics -- Legionella pneumophila ; Biological sciences -- Biology -- Physiology -- Legionella pneumophila
    ISSN: 00278424
    E-ISSN: 10916490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 31 July 2007, Vol.104(31), pp.12896-901
    Description: IraP is a small protein that interferes with the delivery of sigma(S) (RpoS) to the ClpXP protease by blocking the action of RssB, an adaptor protein for sigma(S) degradation. IraP was previously shown to mediate stabilization of sigma(S) during phosphate starvation. Here, we show that iraP is transcribed in response to phosphate starvation; this response is mediated by ppGpp. The iraP promoter is positively regulated by ppGpp, dependent on the discriminator region of the iraP promoter. Sensing of phosphate starvation requires SpoT but not RelA. The results demonstrate a target for positive regulation by ppGpp and suggest that the cell use of ppGpp to mediate a variety of starvation responses operates in part by modulating sigma(S) levels.
    Keywords: Bacterial Proteins -- Genetics ; Escherichia Coli Proteins -- Metabolism ; Sigma Factor -- Genetics
    ISSN: 0027-8424
    E-ISSN: 10916490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages