scholarly journals Membrane proteins associated with amino acid transport by yeast (Saccharomyces cerevisiae)

1980 ◽  
Vol 192 (2) ◽  
pp. 659-664 ◽  
Author(s):  
J R Woodward ◽  
H L Kornberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Membrane Proteins ◽  
Wild Type Strain ◽  
Osmotic Shock ◽  
Wild Type ◽  
Amino Acid Permease ◽  
Yeast Saccharomyces Cerevisiae ◽  
General Amino Acid Permease ◽  
Wild Type Yeast

Cells of the wild-type yeast (Saccharomyces cerevisiae) strain Y185, grown under conditions that de-repress the formation of a general amino acid permease (‘Gap’) system, bind delta-N-chloroacetyl[1-(14)C]ornithine; L- and D-amino acid substrates of the general amino acid permease system protect against this binding. The protein responsible is released from the cells by homogenization or by preparation of protoplasts; it is not released by osmotic shock. This protein is virtually absent from the wild-type strain when it is grown under conditions that repress the general amino acid permease system, and is also absent from a Gap- mutant Y185-His3, selected by its resistance to D-amino acids. This mutant and repressed wild-type cells also fail to form a number of membrane proteins elaborated by de-repressed wild-type cells. It is possible that all these proteins are components of the general amino acid permease system.

scholarly journals Changes in membrane proteins associated with inhibition of the general amino acid permease of yeast (Saccharomyces cerevisiae)

1981 ◽  
Vol 196 (2) ◽  
pp. 531-536 ◽  
Author(s):  
J R Woodward ◽  
H L Kornberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Wild Type ◽  
Amino Acid Permease ◽  
Yeast Saccharomyces Cerevisiae ◽  
General Amino Acid Permease ◽  
Wild Type Yeast

The general amino acid permease (‘Gap’) system of the wild-type yeast (Saccharomyces cerevisiae) strain Y185 is inhibited by the uptake and accumulation of its substrate amino acids. Surprisingly, this inhibition persists even after ‘pools’ of amino acids, accumulated initially, have returned to normal sizes. Recovery from this inhibition depends on a supply of energy and involves the synthesis of a membrane protein component of the Gap system.

scholarly journals MCH4is a multicopy suppressor of glycine toxicity inSaccharomyces cerevisiae

2019 ◽  
Author(s):  
Artem V. Melnykov ◽  
Elliot L. Elson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Osmotic Shock ◽  
Inhibitory Effects ◽  
Amino Acid Permease ◽  
Multicopy Suppressor ◽  
Low Concentrations ◽  
General Amino Acid Permease ◽  
Acid Toxicity

AbstractSaccharomyces cerevisiaecan either import amino acids from the surrounding or synthesize inside the cell, and both processes are tightly regulated. Disruption of such regulation can result in amino acid toxicity to the cell through mechanisms that are poorly understood. In this study we make use of a mutant strain with deregulated general amino acid permease gene whose growth is inhibited by low concentrations of several amino acids. We carry out multicopy suppression screen with several toxic amino acids and identifyMCH4as a gene that suppresses inhibitory effects of glycine. We find that expression ofMCH4is regulated by osmotic shock but not other kinds of stress. These findings are discussed in the context of possible mechanisms of amino acid toxicity.

Ammonia regulation of amino acid permeases in Saccharomyces cerevisiae

1983 ◽  
Vol 3 (4) ◽  
pp. 672-683
Author(s):  
W E Courchesne ◽  
B Magasanik
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Cytoplasmic Membrane ◽  
Nitrogen Sources ◽  
Amino Acid Permease ◽  
Inducer Exclusion ◽  
Amino Acid Permeases ◽  
General Amino Acid Permease ◽  
State Growth ◽  
And Control

The activities of the proline-specific permease (PUT4) and the general amino acid permease (GAP1) of Saccharomyces cerevisiae vary 70- to 140-fold in response to the nitrogen source of the growth medium. The PUT4 and GAP1 permease activities are regulated by control of synthesis and control of activity. These permeases are irreversibly inactivated by addition of ammonia or glutamine, lowering the activity to that found during steady-state growth on these nitrogen sources. Mutants altered in the regulation of the PUT4 permease (Per-) have been isolated. The mutations in these strains are pleiotropic and affect many other permeases, but have no direct effect on various cytoplasmic enzymes involved in nitrogen assimilation. In strains having one class of mutations (per1), ammonia inactivation of the PUT4 and GAP1 permeases did not occur, whereas glutamate and glutamine inactivation did. Thus, there appear to be two independent inactivation systems, one responding to ammonia and one responding to glutamate (or a metabolite of glutamate). The mutations were found to be nuclear and recessive. The inactivation systems are constitutive and do not require transport of the effector molecules per se, apparently operating on the inside of the cytoplasmic membrane. The ammonia inactivation was found not to require a functional glutamate dehydrogenase (NADP). These mutants were used to show that ammonia exerts control of arginase synthesis largely by inducer exclusion. This may be the primary mode of nitrogen regulation for most nitrogen-regulated enzymes of S. cerevisiae.

scholarly journals Topoisomerase I involvement in illegitimate recombination in Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (4) ◽  
pp. 1805-1812 ◽  
Author(s):  
J Zhu ◽  
R H Schiestl
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chromosome Aberrations ◽  
Topoisomerase I ◽  
Wild Type Strain ◽  
Hot Spot ◽  
Illegitimate Recombination ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae

Chromosome aberrations may cause cancer and many heritable diseases. Topoisomerase I has been suspected of causing chromosome aberrations by mediating illegitimate recombination. The effects of deletion and of overexpression of the topoisomerase I gene on illegitimate recombination in the yeast Saccharomyces cerevisiae have been studied. Yeast transformations were carried out with DNA fragments that did not have any homology to the genomic DNA. The frequency of illegitimate integration was 6- to 12-fold increased in a strain overexpressing topoisomerase I compared with that in isogenic control strains. Hot spot sequences [(G/C)(A/T)T] for illegitimate integration target sites accounted for the majority of the additional events after overexpression of topoisomerase I. These hot spot sequences correspond to sequences previously identified in vitro as topoisomerase I preferred cleavage sequences in other organisms. Furthermore, such hot spot sequences were found in 44% of the integration events present in the TOP1 wild-type strain and at a significantly lower frequency in the top1delta strain. Our results provide in vivo evidence that a general eukaryotic topoisomerase I enzyme nicks DNA and ligates nonhomologous ends, leading to illegitimate recombination.

Evolution of ethylene by Saccharomyces cerevisiae as influenced by the carbon source for growth and the presence of air

1978 ◽  
Vol 24 (6) ◽  
pp. 637-642 ◽  
Author(s):  
K. C. Thomas ◽  
Mary Spencer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Ethylene Production ◽  
Atp Synthesis ◽  
Yeast Cells ◽  
Yeast Culture ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Absolute Requirement ◽  
Wild Type Yeast

Effects of the carbon source and oxygen on ethylene production by the yeast Saccharomyces cerevisiae have been studied. The amounts of ethylene evolved by the yeast culture were less than those detected in the blank (an equal volume of uninoculated medium), suggesting a net absorption of ethylene by the yeast cells. Addition of glucose to the lactate-grown yeast culture induced ethylene production. This glucose-induced stimulation of ethylene production was inhibited to a great extent by cycloheximide. Results suggested that the yeast cells in the presence of glucose synthesized an ethylene precursor and passed it into the medium. The conversion of this precursor to ethylene might be stimulated by oxygen. The fact that ethylene was produced by the yeast growing anaerobically and also by respiration-deficient mutants isolated from the wild-type yeast suggested that mitochondrial ATP synthesis was not an absolute requirement for ethylene biogenesis.

scholarly journals Disruption of the RAD52 gene alters the spectrum of spontaneous SUP4-o mutations in Saccharomyces cerevisiae.

Genetics ◽  
1989 ◽  
Vol 122 (3) ◽  
pp. 535-542 ◽  
Author(s):  
B A Kunz ◽  
M G Peters ◽  
S E Kohalmi ◽  
J D Armstrong ◽  
M Glattke ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Base Pair ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mutator Phenotype ◽  
In The Wild ◽  
Single Base Pair ◽  
Almost All

Abstract Defects in the RAD52 gene of the yeast Saccharomyces cerevisiae confer a mutator phenotype. To characterize this effect in detail, a collection of 238 spontaneous SUP4-o mutations arising in a strain having a disrupted RAD52 gene was analyzed by DNA sequencing. The resulting mutational spectrum was compared to that derived from an examination of 222 spontaneous mutations selected in a nearisogenic wild-type (RAD52) strain. This comparison revealed that the mutator phenotype was associated with an increase in the frequency of base-pair substitutions. All possible types of substitution were detected but there was a reduction in the relative fraction of A.T----G.C transitions and an increase in the proportion of G.C----C.G transversions. These changes were sufficient to cause a twofold greater preference for substitutions at G.C sites in the rad52 strain despite a decrease in the fraction of G.C----T.A transversions. There were also considerable differences between the distributions of substitutions within the SUP4-o gene. Base-pair changes occurred at fewer sites in the rad52 strain but the mutated sites included several that were not detected in the RAD52 background. Only two of the four sites that were mutated most frequently in the rad52 strain were also prominent in the wild-type strain and mutation frequencies at almost all sites common to both strains were greater for the rad52 derivative. Although single base-pair deletions occurred in the two strains with similar frequencies, several classes of mutation that were recovered in the wild-type background including multiple base-pair deletions, insertions of the yeast transposable element Ty, and more complex changes, were not detected in the rad52 strain.(ABSTRACT TRUNCATED AT 250 WORDS)

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