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.

Altered mitochondrial ribosomes in a cold-sensitive mutant of Saccharomyces cerevisiae

1978 ◽  
Vol 4 (2) ◽  
pp. 83-86 ◽  
Author(s):  
Terence W. Spithill ◽  
K. J. English ◽  
Phillip Nagley ◽  
Anthony W. Linnane
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sensitive Mutant ◽  
Mitochondrial Ribosomes ◽  
Cold Sensitive

scholarly journals Suppression of a cold-sensitive mutant initiation factor 1 by alterations in the 23S rRNA maturation region

FEBS Journal ◽  
2011 ◽  
Vol 278 (10) ◽  
pp. 1745-1756 ◽  
Author(s):  
Jaroslav M. Belotserkovsky ◽  
Georgina I. Isak ◽  
Leif A. Isaksson
Keyword(s):  
Initiation Factor ◽  
23S Rrna ◽  
Sensitive Mutant ◽  
Cold Sensitive ◽  
Rrna Maturation

Cold sensitive mutant of Escherichia coli with altered RNA polymerase

1974 ◽  
Vol 130 (1) ◽  
pp. 1-7 ◽  
Author(s):  
V. G. Nikiforov ◽  
E. S. Kalyaeva ◽  
V. V. Velkov
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Sensitive Mutant ◽  
Cold Sensitive

scholarly journals Changes in Listeria monocytogenes Membrane Fluidity in Response to Temperature Stress

2007 ◽  
Vol 73 (20) ◽  
pp. 6429-6435 ◽  
Author(s):  
Mohamed Badaoui Najjar ◽  
Michael Chikindas ◽  
Thomas J. Montville
Keyword(s):  
Listeria Monocytogenes ◽  
Membrane Fluidity ◽  
The Other ◽  
Sensitive Mutant ◽  
Homeoviscous Adaptation ◽  
Whole Cells ◽  
Food Borne ◽  
Cold Sensitive ◽  
The Difference ◽  
Response To Temperature

ABSTRACT Listeria monocytogenes is a food-borne pathogen that has been implicated in many outbreaks associated with ready-to-eat products. Listeria adjusts to various stresses by adjusting its membrane fluidity, increasing the uptake of osmoprotectants and cryoprotectants, and activating the σB stress factor. The present work examines the regulation of membrane fluidity through direct measurement based on fluorescent anisotropy. The membrane fluidities of L. monocytogenes Scott A, NR30, wt10403S, and cld1 cells cultured at 15 and 30°C were measured at 15 and 30°C. The membrane of the cold-sensitive mutant (cld1) was more rigid than the membranes of the other strains when grown at 30°C, but when grown at 15°C, it was able to adjust its membrane to approach the rigidity of the other strains. The difference in rigidities, as determined at 15 and 30°C, was greater in liposomes than in whole cells. The rates of fluidity adjustment and times required for whole cells to adjust to a different temperature were similar among strains but different from those of liposomes. This suggests that the cells had a mechanism for homeoviscous adaptation that was absent in liposomes.

scholarly journals Validation of an ampicillin selection protocol to enrich for mutants of Listeria monocytogenes unable to replicate on fresh produce

2019 ◽  
Vol 366 (7) ◽  
Author(s):  
Victor Jayeola ◽  
C Parsons ◽  
L Gorski ◽  
S Kathariou
Keyword(s):  
Listeria Monocytogenes ◽  
Genetic Factors ◽  
Fresh Produce ◽  
Mixed Cultures ◽  
Bacterial Cells ◽  
Sensitive Mutant ◽  
Relative Recovery ◽  
Cold Sensitive ◽  
Selection Protocol

ABSTRACT Several outbreaks of listeriosis have implicated fresh produce but genetic factors required for growth of Listeria monocytogenes on produce remain poorly characterized. Based on the fact that β-lactam antibiotics only kill bacterial cells that are growing, we hypothesized that ampicillin selection can enrich for L. monocytogenes mutants unable to grow on produce. For validation, we examined relative recovery of L. monocytogenes strain 2011L-2858 and its cold-sensitive mutant L1E4 following inoculation of cantaloupe rind fragments with 1:1 mixture of the strains and incubation at 4°C with or without ampicillin. Listeria monocytogenes from rind fragments inoculated with the mixed cultures and incubated in the presence of ampicillin were used to inoculate fresh rind fragments for a second round of enrichment. In the presence of ampicillin, the proportion of L1E4 increased from 55% on day 0 to 78% on day 14, with higher recovery (85% after 14 days) in the second round of enrichment. These data suggested that L1E4 was enriched on cantaloupe rind fragments while growing cells of the wildtype were killed by ampicillin. Application of this protocol to transposon mutant libraries from three L. monocytogenes strains yielded several mutants unable to grow on cantaloupe. Thus, ampicillin selection can facilitate discovery of genes essential for growth of L. monocytogenes on fresh produce.

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