scholarly journals PILS6 is a temperature-sensitive regulator of nuclear auxin input and organ growth in Arabidopsis thaliana

2018 ◽  
Author(s):  
Elena Feraru ◽  
Mugurel I. I Feraru ◽  
Elke Barbez ◽  
Lin Sun ◽  
Angelika Gaidora ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Negative Regulator ◽  
Root Tip ◽  
Temperature Sensitive ◽  
Protein Abundance ◽  
Organ Growth ◽  
Auxin Signalling ◽  
Highly Sensitive ◽  
Auxin Carrier ◽  
Dependent Growth

Global warming is threatening plant productivity, because plant growth is highly sensitive to elevated temperatures. High temperature (HT) triggers the auxin biosynthesis-dependent growth in aerial tissues. On the other hand, the contribution of auxin to HT-induced root growth is currently under debate. Here we show that the putative intracellular auxin carrier PIN-LIKES 6 (PILS6) is a negative regulator of organ growth and that its abundance is highly sensitive to HT. PILS6 localises to the endoplasmic reticulum (ER) and limits the nuclear availability of auxin, consequently reducing the auxin signalling output. HT represses the transcription and protein abundance of PILS6 specifically in the root tip, which impacts on PILS6-dependent root organ growth rates. Accordingly, we hypothesize that PILS6 is part of a novel mechanism, linking HT to auxin responses in roots.

scholarly journals PILS6 is a temperature-sensitive regulator of nuclear auxin input and organ growth in Arabidopsis thaliana

2019 ◽  
Vol 116 (9) ◽  
pp. 3893-3898 ◽  
Author(s):  
Elena Feraru ◽  
Mugurel I. Feraru ◽  
Elke Barbez ◽  
Sascha Waidmann ◽  
Lin Sun ◽  
...  
Keyword(s):  
Growth And Development ◽  
Negative Regulator ◽  
Auxin Signaling ◽  
Temperature Sensitive ◽  
Alternative Mechanism ◽  
Protein Abundance ◽  
Organ Growth ◽  
Highly Sensitive ◽  
Auxin Carrier ◽  
Dependent Growth

Temperature modulates growth and development throughout the entire lifecycle of a plant. High temperature (HT) triggers the auxin biosynthesis-dependent growth in aerial tissues. On the other hand, the contribution of auxin to HT-induced root growth is currently under debate. Here we show that the putative intracellular auxin carrier PIN-LIKES 6 (PILS6) is a negative regulator of organ growth and that its abundance is highly sensitive to HT. PILS6 localizes to the endoplasmic reticulum and limits the nuclear availability of auxin, consequently reducing the auxin signaling output. HT represses the PILS6 protein abundance, which impacts on PILS6-dependent auxin signaling in roots and root expansion. Accordingly, we hypothesize that PILS6 is part of an alternative mechanism linking HT to auxin responses in roots.

scholarly journals Auxin regulates SNARE-dependent vacuolar morphology restricting cell size

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Christian Löfke ◽  
Kai Dünser ◽  
David Scheuring ◽  
Jürgen Kleine-Vehn
Keyword(s):  
Cell Wall ◽  
Cell Size ◽  
Growth Regulation ◽  
Cellular Growth ◽  
Protein Abundance ◽  
Loss Of Function ◽  
Organ Growth ◽  
Auxin Signalling ◽  
Dependent Growth ◽  
Auxin Effect

The control of cellular growth is central to multicellular patterning. In plants, the encapsulating cell wall literally binds neighbouring cells to each other and limits cellular sliding/migration. In contrast to its developmental importance, growth regulation is poorly understood in plants. Here, we reveal that the phytohormone auxin impacts on the shape of the biggest plant organelle, the vacuole. TIR1/AFBs-dependent auxin signalling posttranslationally controls the protein abundance of vacuolar SNARE components. Genetic and pharmacological interference with the auxin effect on vacuolar SNAREs interrelates with auxin-resistant vacuolar morphogenesis and cell size regulation. Vacuolar SNARE VTI11 is strictly required for auxin-reliant vacuolar morphogenesis and loss of function renders cells largely insensitive to auxin-dependent growth inhibition. Our data suggests that the adaptation of SNARE-dependent vacuolar morphogenesis allows auxin to limit cellular expansion, contributing to root organ growth rates.

scholarly journals Mutations in the Bacillus subtilis β Clamp That Separate Its Roles in DNA Replication from Mismatch Repair

2010 ◽  
Vol 192 (13) ◽  
pp. 3452-3463 ◽  
Author(s):  
Nicole M. Dupes ◽  
Brian W. Walsh ◽  
Andrew D. Klocko ◽  
Justin S. Lenhart ◽  
Heather L. Peterson ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Dna Replication ◽  
Mismatch Repair ◽  
Mutation Frequency ◽  
Elevated Temperatures ◽  
Temperature Sensitive ◽  
Mutant Form ◽  
Appreciable Effect ◽  
Missense Mutations ◽  
Dna Mismatch

ABSTRACT The β clamp is an essential replication sliding clamp required for processive DNA synthesis. The β clamp is also critical for several additional aspects of DNA metabolism, including DNA mismatch repair (MMR). The dnaN5 allele of Bacillus subtilis encodes a mutant form of β clamp containing the G73R substitution. Cells with the dnaN5 allele are temperature sensitive for growth due to a defect in DNA replication at 49°C, and they show an increase in mutation frequency caused by a partial defect in MMR at permissive temperatures. We selected for intragenic suppressors of dnaN5 that rescued viability at 49°C to determine if the DNA replication defect could be separated from the MMR defect. We isolated three intragenic suppressors of dnaN5 that restored growth at the nonpermissive temperature while maintaining an increase in mutation frequency. All three dnaN alleles encoded the G73R substitution along with one of three novel missense mutations. The missense mutations isolated were S22P, S181G, and E346K. Of these, S181G and E346K are located near the hydrophobic cleft of the β clamp, a common site occupied by proteins that bind the β clamp. Using several methods, we show that the increase in mutation frequency resulting from each dnaN allele is linked to a defect in MMR. Moreover, we found that S181G and E346K allowed growth at elevated temperatures and did not have an appreciable effect on mutation frequency when separated from G73R. Thus, we found that specific residue changes in the B. subtilis β clamp separate the role of the β clamp in DNA replication from its role in MMR.

Production of the CYS3 regulator, a bZIP DNA-binding protein, is sufficient to induce sulfur gene expression in Neurospora crassa

1992 ◽  
Vol 12 (4) ◽  
pp. 1568-1577
Author(s):  
J V Paietta
Keyword(s):  
Gene Expression ◽  
Neurospora Crassa ◽  
Structural Gene ◽  
Control Point ◽  
Regulatory Protein ◽  
Negative Regulator ◽  
Temperature Sensitive ◽  
Cys3 Protein

The cys-3+ gene of Neurospora crassa encodes a bZIP (basic region-leucine zipper) regulatory protein that is essential for sulfur structural gene expression (e.g., ars-1+). Nuclear transcription assays confirmed that cys-3+ was under sulfur-regulated transcriptional control and that cys-3+ transcription was constitutive in sulfur controller (scon)-negative regulator mutants. Given these results, I have tested whether expression of cys-3+ under high-sulfur (repressing) conditions was sufficient to induce sulfur gene expression. The N. crassa beta-tubulin (tub) promoter was fused to the cys-3+ coding segment and used to transform a cys-3 deletion mutant. Function of the tub::cys-3 fusion in homokaryotic transformants grown under high-sulfur conditions was confirmed by Northern (RNA) and Western immunoblot analysis. The tub::cys-3 transformants showed arylsulfatase gene expression under normally repressing high-sulfur conditions. A tub::cys-3ts fusion encoding a temperature-sensitive CYS3 protein was used to confirm that the induced structural gene expression was due to CYS3 protein function. Constitutive CYS3 production did not induce scon-2+ expression under repressing conditions. In addition, a cys-3 promoter fusion to lacZ showed that CYS3 production was sufficient to induce its own expression and provides in vivo evidence for autoregulation. Finally, an apparent inhibitory effect observed with a strain carrying a point mutation at the cys-3 locus was examined by in vitro heterodimerization studies. These results support an interpretation of CYS3 as a transcriptional activator whose regulation is a crucial control point in the signal response pathway triggered by sulfur limitation.

scholarly journals Absence of the Outer Membrane Phospholipase A Suppresses the Temperature-Sensitive Phenotype of Escherichia coli degPMutants and Induces the Cpx and ςE Extracytoplasmic Stress Responses

2001 ◽  
Vol 183 (18) ◽  
pp. 5230-5238 ◽  
Author(s):  
Geoffrey R. Langen ◽  
Jill R. Harper ◽  
Thomas J. Silhavy ◽  
S. Peter Howard
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Stress Responses ◽  
Elevated Temperatures ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Phospholipase A ◽  
Temperature Sensitive ◽  
Outer Membrane Phospholipase A ◽  
Temperature Sensitive Phenotype

ABSTRACT DegP is a periplasmic protease that is a member of both the ςE and Cpx extracytoplasmic stress regulons ofEscherichia coli and is essential for viability at temperatures above 42°C. [U-14C]acetate labeling experiments demonstrated that phospholipids were degraded indegP mutants at elevated temperatures. In addition, chloramphenicol acetyltransferase, β-lactamase, and β-galactosidase assays as well as sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis indicated that large amounts of cellular proteins are released from degP cells at the nonpermissive temperature. A mutation in pldA, which encodes outer membrane phospholipase A (OMPLA), was found to rescue degPcells from the temperature-sensitive phenotype. pldA degP mutants had a normal plating efficiency at 42°C, displayed increased viability at 44°C, showed no degradation of phospholipids, and released far lower amounts of cellular protein to culture supernatants. degP and pldA degP mutants containing chromosomal lacZ fusions to Cpx and ςE regulon promoters indicated that both regulons were activated in the pldA mutants. The overexpression of the envelope lipoprotein, NlpE, which induces the Cpx regulon, was also found to suppress the temperature-sensitive phenotype ofdegP mutants but did not prevent the degradation of phospholipids. These results suggest that the absence of OMPLA corrects the degP temperature-sensitive phenotype by inducing the Cpx and ςE regulons rather than by inactivating the phospholipase per se.

KEX2 mutations suppress RNA polymerase II mutants and alter the temperature range of yeast cell growth

1989 ◽  
Vol 9 (6) ◽  
pp. 2341-2349
Author(s):  
C Martin ◽  
R A Young
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Single Gene ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Temperature Dependent ◽  
Growth Properties ◽  
Cold Sensitive ◽  
Dependent Growth ◽  
Kex2 Protease

Suppressors of a temperature-sensitive RNA polymerase II mutation were isolated to identify proteins that interact with RNA polymerase II in yeast cells. Ten independently isolated extragenic mutations that suppressed the temperature-sensitive mutation rpb1-1 and produced a cold-sensitive phenotype were all found to be alleles of a single gene, SRB1. An SRB1 partial deletion mutant was further investigated and found to exhibit several pleiotropic phenotypes. These included suppression of numerous temperature-sensitive RNA polymerase II mutations, alteration of the temperature growth range of cells containing wild-type RNA polymerase, and sterility of cells of alpha mating type. The ability of SRB1 mutations to suppress the temperature-sensitive phenotype of RNA polymerase II mutants did not extend to other temperature-sensitive mutants investigated. Isolation of the SRB1 gene revealed that SRB1 is KEX2. These results indicate that the KEX2 protease, whose only known substrates are hormone precursors, can have an important influence on RNA polymerase II and the temperature-dependent growth properties of yeast cells.

Putative GTPase Gtr1p genetically interacts with the RanGTPase cycle in Saccharomyces cerevisiae

1996 ◽  
Vol 109 (9) ◽  
pp. 2311-2318 ◽  
Author(s):  
N. Nakashima ◽  
N. Hayashi ◽  
E. Noguchi ◽  
T. Nishimoto
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Negative Regulator ◽  
Temperature Sensitive ◽  
Nucleotide Exchange ◽  
Sensitive Mutant ◽  
Temperature Sensitive Mutant ◽  
Importin Alpha ◽  
Nucleotide Exchange Factor ◽  
Cold Sensitive ◽  
Gtpase Cycle

In order to identify a protein interacting with RCC1, a guanine nucleotide-exchange factor for the nuclear GTPase Ran, we isolated a series of cold-sensitive suppressors of mtr1-2, a temperature-sensitive mutant of the Saccharomyces cerevisiae RCC1 homologue. One of the isolated suppressor mutants was mutated in the putative GTPase Gtr1p, being designated as gtr1-11. It also suppressed other alleles of mtr1-2, srm1-1 and prp20-1 in contrast to overexpression of the S. cerevisiae Ran/TC4 homologue Gsp1p, previously reported to suppress prp20-1, but not mtr1-2 or srm1-1. Furthermore, gtr1-11 suppressed the rna1-1, temperature-sensitive mutant of the Gsp1p GTPase-activating protein, but not the srp1-31, temperature-sensitive mutant of the S. cerevisiae importin alpha homologue. mtr1-2, srm1-1 and prp20-1 were also suppressed by overexpression of the mutated Gtr1p, Gtr1-11p. In summary, Gtr1p that was localized in the cytoplasm by immunofluoresence staining was suggested to function as a negative regulator for the Ran/TC4 GTPase cycle.

Fracture Behavior of Ultrafine-Grained Titanium Under Tension at Elevated Temperatures

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
S. V. Sajadifar ◽  
H. J. Maier ◽  
T. Niendorf ◽  
G. G. Yapici
Keyword(s):  
Fracture Behavior ◽  
Elevated Temperatures ◽  
Rate Sensitivity ◽  
Void Coalescence ◽  
Strain Rates ◽  
Enhanced Diffusion ◽  
Deformation Response ◽  
Ultrafine Grained ◽  
Highly Sensitive ◽  
Comprehensive Recovery

Abstract This investigation focused on the deformation response and microstructural changes of severely deformed titanium during post-severe plastic deformation tension, at temperatures of 300–600 °C and at strain rates of 0.001–0.1 s−1. The obtained results suggest that SPD enhances the strength of grade 4 titanium up to 500 °C. At above 600 °C, the severely deformed microstructure showed comprehensive recovery. Severely deformed titanium was seen to be highly sensitive to the deformation rate, where strain rate sensitivity increased with the increase of test temperature. Analysis of fracture surfaces reveals that at elevated temperatures, growth of dimples and void coalescence occurs due to the enhanced diffusion rate and occurrence of recrystallized grains.

scholarly journals Mistranslating tRNA identifies a deleterious S213P mutation in the Saccharomyces cerevisiae eco1-1 allele

2020 ◽  
Vol 98 (5) ◽  
pp. 624-630 ◽  
Author(s):  
Yanrui Zhu ◽  
Matthew D. Berg ◽  
Phoebe Yang ◽  
Raphaël Loll-Krippleber ◽  
Grant W. Brown ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Genetic Disease ◽  
Elevated Temperatures ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Standard Genetic Code ◽  
Gene Encoding ◽  
Chromatid Cohesion ◽  
Sensitive Allele

Mistranslation occurs when an amino acid not specified by the standard genetic code is incorporated during translation. Since the ribosome does not read the amino acid, tRNA variants aminoacylated with a non-cognate amino acid or containing a non-cognate anticodon dramatically increase the frequency of mistranslation. In a systematic genetic analysis, we identified a suppression interaction between tRNASerUGG, G26A, which mistranslates proline codons by inserting serine, and eco1-1, a temperature sensitive allele of the gene encoding an acetyltransferase required for sister chromatid cohesion. The suppression was partial, with a tRNA that inserts alanine at proline codons and not apparent for a tRNA that inserts serine at arginine codons. Sequencing of the eco1-1 allele revealed a mutation that would convert the highly conserved serine 213 within β7 of the GCN5-related N-acetyltransferase core to proline. Mutation of P213 in eco1-1 back to the wild-type serine restored the function of the enzyme at elevated temperatures. Our results indicate the utility of mistranslating tRNA variants to identify functionally relevant mutations and identify eco1 as a reporter for mistranslation. We propose that mistranslation could be used as a tool to treat genetic disease.

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