Reduction of the translation fidelity by kanamycin: effects on growth and mutant frequency in S. typhimurium TA102

1989 ◽  
Vol 226 (3) ◽  
pp. 211-214 ◽  
Author(s):  
Elmar Gocke
Keyword(s):  
Translation Fidelity ◽  
Mutant Frequency

scholarly journals Identification of the Genes Encoding the Cytosolic Translation Release Factors from Podospora anserina and Analysis of Their Role During the Life Cycle

Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 1763-1775 ◽  
Author(s):  
Bénédicte Gagny ◽  
Philippe Silar
Keyword(s):  
Life Span ◽  
Translation Termination ◽  
Podospora Anserina ◽  
Terminal Region ◽  
Terminal Portion ◽  
Nonsense Mutations ◽  
Translation Fidelity ◽  
Reproductive Impairment ◽  
Genes Encoding ◽  
Nonsense Suppressor

Abstract In an attempt to decipher their role in the life history and senescence process of the filamentous fungus Podospora anserina, we have cloned the su1 and su2 genes, previously identified as implicated in cytosolic translation fidelity. We show that these genes are the equivalents of the SUP35 and SUP45 genes of Saccharomyces cerevisiae, which encode the cytosolic translation termination factors eRF3 and eRF1, respectively. Mutations in these genes that suppress nonsense mutations may lead to drastic mycelium morphology changes and sexual impairment but have little effect on life span. Deletion of su1, coding for the P. anserina eRF3, is lethal. Diminution of its expression leads to a nonsense suppressor phenotype whereas its overexpression leads to an antisuppressor phenotype. P. anserina eRF3 presents an N-terminal region structurally related to the yeast eRF3 one. Deletion of the N-terminal region of P. anserina eRF3 does not cause any vegetative alteration; especially life span is not changed. However, it promotes a reproductive impairment. Contrary to what happens in S. cerevisiae, deletion of the N terminus of the protein promotes a nonsense suppressor phenotype. Genetic analysis suggests that this domain of eRF3 acts in P. anserina as a cis-activator of the C-terminal portion and is required for proper reproduction.

An analysis of in vivo hprt mutant frequency in circulating T-lymphocytes in the normal human population: a comparison of four datasets

1994 ◽  
Vol 313 (2-3) ◽  
pp. 227-247 ◽  
Author(s):  
Derek R. Robinson ◽  
Kevin Goodall ◽  
Richard J. Albertini ◽  
J.Patrick O'Neill ◽  
Barry Finette ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Human Population ◽  
Normal Human ◽  
Mutant Frequency

scholarly journals A platform for deep sequence-activity mapping and engineering antimicrobial peptides

2021 ◽  
Author(s):  
Matt P. DeJong ◽  
Seth C. Ritter ◽  
Katharina A. Fransen ◽  
Daniel T. Tresnak ◽  
Alexander W Golinski ◽  
...  
Keyword(s):  
Peptide Library ◽  
Mutant Library ◽  
Library Design ◽  
Bacterial Host ◽  
Host Culture ◽  
Rate Versus ◽  
High Throughput Method ◽  
Extracellular Activity ◽  
Mutant Frequency ◽  
Broad Continuum

Developing potent antimicrobials, and platforms for their study and engineering, is critical as antibiotic resistance grows. A high-throughput method to quantify antimicrobial peptide and protein (AMP) activity across a broad continuum can elucidate sequence-activity landscapes and identify potent mutants. We developed a platform to perform sequence-activity mapping of AMPs via depletion (SAMP-Dep): a bacterial host culture is transformed with an AMP mutant library, induced to express AMPs, grown, and deep sequenced to quantify mutant frequency. The slope of mutant growth rate versus induction level indicates potency. Using SAMP-Dep, we screened 170,000 mutants of oncocin, a proline-rich AMP, for intracellular activity against Escherichia coli. Clonal validation of 36 mutants supported SAMP-Dep sensitivity and accuracy. The efficiency and accuracy of SAMP-Dep enabled mapping the oncocin sequence-activity space with remarkable detail and scale and guided focused, successful synthetic peptide library design, yielding a mutant with two-fold enhancement in both intracellular and extracellular activity.

scholarly journals Structural insights into mRNA reading frame regulation by tRNA modification and slippery codon-anticodon pairing

2020 ◽  
Author(s):  
Eric D. Hoffer ◽  
Samuel Hong ◽  
S. Sunita ◽  
Tatsuya Maehigashi ◽  
Ruben L. Gonzalez ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Data Bank ◽  
Reading Frame ◽  
Translation Fidelity ◽  
Bacterial Ribosome ◽  
Structure Factors ◽  
Sequential Addition ◽  
Polypeptide Chains ◽  
Structural Insights ◽  
Atomic Coordinates

ABSTRACTModifications in the tRNA anticodon, adjacent to the three-nucleotide anticodon, influence translation fidelity by stabilizing the tRNA to allow for accurate reading of the mRNA genetic code. One example is the N1-methylguaonosine modification at guanine nucleotide 37 (m1G37) located in the anticodon loop, immediately adjacent to the anticodon nucleotides 34-36. The absence of m1G37 in tRNAPro causes +1 frameshifting on polynucleotide, slippery codons. Here, we report structures of the bacterial ribosome containing tRNAPro bound to either cognate or slippery codons to determine how the m1G37 modification prevents mRNA frameshifting. The structures reveal that certain codon-anticodon contexts and m1G37 destabilize interactions of tRNAPro with the peptidyl site, causing large conformational changes typically only seen during EF-G mediated translocation of the mRNA-tRNA pairs. These studies provide molecular insights into how m1G37 stabilizes the interactions of tRNAPro with the ribosome and the influence of slippery codons on the mRNA reading frame.IMPACT STATEMENTChemical modifications near the tRNA anticodon and specific mRNA-tRNA pairs combine to control the ribosomal three-nucleotide mRNA reading frame, essential for the sequential addition of amino acids into polypeptide chains.Data depositionCrystallography, atomic coordinates, and structure factors have been deposited in the Protein Data Bank, www.pdb.org (PDB codes 6NTA, 6NSH, 6NUO, 6NWY, 6O3M, 6OSI)

scholarly journals Production and Application of Stable Isotope-Labeled Internal Standards for RNA Modification Analysis

Genes ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 26 ◽  
Author(s):  
Kayla Borland ◽  
Jan Diesend ◽  
Taku Ito-Kureha ◽  
Vigo Heissmeyer ◽  
Christian Hammann ◽  
...  
Keyword(s):  
Messenger Rna ◽  
Isotope Labeling ◽  
Rna Stability ◽  
Internal Standard ◽  
Modified Nucleosides ◽  
Rna Modification ◽  
Mouse Tissue ◽  
Rna Modifications ◽  
Internal Standards ◽  
Translation Fidelity

Post-transcriptional RNA modifications have been found to be present in a wide variety of organisms and in different types of RNA. Nucleoside modifications are interesting due to their already known roles in translation fidelity, enzyme recognition, disease progression, and RNA stability. In addition, the abundance of modified nucleosides fluctuates based on growth phase, external stress, or possibly other factors not yet explored. With modifications ever changing, a method to determine absolute quantities for multiple nucleoside modifications is required. Here, we report metabolic isotope labeling to produce isotopically labeled internal standards in bacteria and yeast. These can be used for the quantification of 26 different modified nucleosides. We explain in detail how these internal standards are produced and show their mass spectrometric characterization. We apply our internal standards and quantify the modification content of transfer RNA (tRNA) from bacteria and various eukaryotes. We can show that the origin of the internal standard has no impact on the quantification result. Furthermore, we use our internal standard for the quantification of modified nucleosides in mouse tissue messenger RNA (mRNA), where we find different modification profiles in liver and brain tissue.

scholarly journals Spontaneous Mutagenesis Is Enhanced in Apex Heterozygous Mice

2004 ◽  
Vol 24 (18) ◽  
pp. 8145-8153 ◽  
Author(s):  
Jessica Huamani ◽  
C. Alex McMahan ◽  
Damon C. Herbert ◽  
Robert Reddick ◽  
John R. McCarrey ◽  
...  
Keyword(s):  
Base Excision Repair ◽  
Germ Line ◽  
Excision Repair ◽  
Spontaneous Mutant ◽  
Spermatogenic Cells ◽  
Ap Endonuclease ◽  
Repair Activity ◽  
Base Excision ◽  
Mutant Frequency

ABSTRACT Germ line DNA directs the development of the next generation and, as such, is profoundly different from somatic cell DNA. Spermatogenic cells obtained from young adult lacI transgenic mice display a lower spontaneous mutant frequency and greater in vitro base excision repair activity than somatic cells and tissues obtained from the same mice. However, spermatogenic cells from old lacI mice display a 10-fold higher mutant frequency. This increased spontaneous mutant frequency occurs coincidentally with decreased in vitro base excision repair activity for germ cell and testicular extracts that in turn corresponds to a decreased abundance of AP endonuclease. To directly test whether a genetic diminution of AP endonuclease results in increased spontaneous mutant frequencies in spermatogenic cell types, AP endonuclease heterozygous (Apex +/−) knockout mice were crossed with lacI transgenic mice. Spontaneous mutant frequencies were significantly elevated (approximately twofold) for liver and spleen obtained from 3-month-old Apex +/− lacI + mice compared to frequencies from Apex +/+ lacI + littermates and were additionally elevated for somatic tissues from 9-month-old mice. Spermatogenic cells from 9-month-old Apex +/− lacI + mice were significantly elevated twofold compared to levels for 9-month-old Apex +/+ lacI + control mice. These data indicate that diminution of AP endonuclease has a significant effect on spontaneous mutagenesis in somatic and germ line cells.

Spontaneous mutant frequency of lacZ gene in spleen of transgenic mouse increases with age

1995 ◽  
Vol 338 (1-6) ◽  
pp. 183-188 ◽  
Author(s):  
T. Ono ◽  
Y. Miyamura ◽  
H. Ikehata ◽  
H. Yamanaka ◽  
A. Kurishita ◽  
...  
Keyword(s):  
Transgenic Mouse ◽  
Lacz Gene ◽  
Spontaneous Mutant ◽  
Mutant Frequency
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