Mitochondrial Transfer in Saccharomyces cerevisiae

Mapping Intimacies ◽

10.26686/wgtn.17136044 ◽

2021 ◽

Author(s):

◽

Sonja Hummel

Keyword(s):

Saccharomyces Cerevisiae ◽

Fluorescent Protein ◽

Single Gene ◽

Mitochondrial Protein ◽

Carbon Sources ◽

Occurrence Frequency ◽

Low Frequencies ◽

Mitochondrial Transfer ◽

Donor Cells ◽

Genotypic Analysis

<p>This thesis investigated mitochondrial transfer in Saccharomyces cerevisiae, between respiratory compromised B18p⁰ recipient and respiratory competent donor cells. The respiratory compromised strain had three red fluorescent proteins tagged to the membrane, nucleus and cytoplasm (triple RFP-B18p⁰) and is referred to as the B18p⁰ strain. B18p⁰ cells did not contain mitochondrial DNA, causing it to be respiratory compromised and required a fermentable carbon source, such as glucose/dextrose, for proliferation. The respiratory competent strain used had a green fluorescent protein tagged to the Tom70 mitochondrial protein (Tom70-GFP) and is referred to as the Tom70 strain. The Tom70 cells contained the nuclear encoded URA3 cassette, allowing for negative selectivity of this strain using 5-FOA. S. cerevisiae strains were co-cultured together in media containing only non-fermentable carbon sources (YPGE), plated on YPGE plates containing 5-FOA and colonies grown were distinguished post-co-culture based on their distinct phenotypic and genotypic characteristics. Fluorescent analysis of co-culture colonies revealed the presence of 5-FOA resistant Tom70 cells and some red B18p⁰ cells that had acquired the ability to grow on non-fermentable carbon sources. Genotypic analysis revealed that the majority of these red colonies had acquired mtDNA as well as the nuclear encoded, Tom70 specific URA3 cassette. Several permutations of co-cultures were performed, using different ratios of recipient and donor cells and single-gene deletion donor cells. Purified mitochondria from Tom70 cells were tried to be transferred into B18p⁰ cells using centrifugation forces to induce a higher occurrence frequency of mitochondrial transfer. Metabolic support experiments were conducted to investigate if the Tom70 strain could provide metabolic support to the B18p⁰ strain without mitochondrial transfer. Results indicate that no permutation induced potential mitochondrial transfer at a higher rate than others. However, results indicate that mitochondrial transfer did occur at low frequencies, potentially through the fusion of respiratory competent and respiratory compromised cells. Forced transfer did not increase the occurrence frequency of B18p⁰ cells to take up mitochondria and Tom70 cells did not provide metabolic support to B18p⁰ cells.</p>

Download Full-text

Mitochondrial Transfer in Saccharomyces cerevisiae

10.26686/wgtn.17136044.v1 ◽

2021 ◽

Author(s):

◽

Sonja Hummel

Keyword(s):

Saccharomyces Cerevisiae ◽

Fluorescent Protein ◽

Single Gene ◽

Mitochondrial Protein ◽

Carbon Sources ◽

Occurrence Frequency ◽

Low Frequencies ◽

Mitochondrial Transfer ◽

Donor Cells ◽

Genotypic Analysis

Download Full-text

The Cloning and Mapping of ADR6, a Gene Required for Sporulation and for Expression of the Alcohol Dehydrogenase II Isozyme From Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/116.4.531 ◽

1987 ◽

Vol 116 (4) ◽

pp. 531-540

Author(s):

Aileen K W Taguchi ◽

Elton T Young

Keyword(s):

Saccharomyces Cerevisiae ◽

Alcohol Dehydrogenase ◽

Single Gene ◽

Carbon Sources ◽

Transcription Unit ◽

Yeast Cells ◽

Recessive Mutation ◽

Yeast Saccharomyces Cerevisiae ◽

Upstream Activating Sequence ◽

A Site

ABSTRACT The alcohol dehydrogenase II (ADH2) gene of the yeast, Saccharomyces cerevisiae, is not transcribed during growth on fermentable carbon sources such as glucose. Growth of yeast cells in a medium containing only nonfermentable carbon sources leads to a marked increase or derepression of ADH2 expression. The recessive mutation, adr6-1, leads to an inability to fully derepress ADH2 expression and to an inability to sporulate. The ADR6 gene product appears to act directly or indirectly on ADH2 sequences 3' to or including the presumptive TATAA box. The upstream activating sequence (UAS) located 5' to the TATAA box is not required for the Adr6- phenotype. Here, we describe the isolation of a recombinant plasmid containing the wild-type ADR6 gene. ADR6 codes for a 4.4-kb RNA which is present during growth both on glucose and on nonfermentable carbon sources. Disruption of the ADR6 transcription unit led to viable cells with decreased ADHII activity and an inability to sporulate. This indicates that both phenotypes result from mutations within a single gene and that the adr6-1 allele was representative of mutations at this locus. The ADR6 gene mapped to the left arm of chromosome XVI at a site 18 centimorgans from the centromere.

Download Full-text

Metabolic and Developmental Effects Resulting from Deletion of the citA Gene Encoding Citrate Synthase in Aspergillus nidulans

Eukaryotic Cell ◽

10.1128/ec.00373-09 ◽

2010 ◽

Vol 9 (4) ◽

pp. 656-666 ◽

Cited By ~ 9

Author(s):

Sandra L. Murray ◽

Michael J. Hynes

Keyword(s):

Aspergillus Nidulans ◽

Fluorescent Protein ◽

Citrate Synthase ◽

Glyoxylate Cycle ◽

Single Gene ◽

Carbon Sources ◽

Tca Cycle ◽

Poor Growth ◽

Content Type ◽

The Glyoxylate Cycle

ABSTRACT Citrate synthase is a central activity in carbon metabolism. It is required for the tricarboxylic acid (TCA) cycle, respiration, and the glyoxylate cycle. In Saccharomyces cerevisiae and Arabidopsis thaliana, there are mitochondrial and peroxisomal isoforms encoded by separate genes, while in Aspergillus nidulans, a single gene, citA, encodes a protein with predicted mitochondrial and peroxisomal targeting sequences (PTS). Deletion of citA results in poor growth on glucose but not on derepressing carbon sources, including those requiring the glyoxylate cycle. Growth on glucose is restored by a mutation in the creA carbon catabolite repressor gene. Methylcitrate synthase, required for propionyl-coenzyme A (CoA) metabolism, has previously been shown to have citrate synthase activity. We have been unable to construct the mcsAΔ citAΔ double mutant, and the expression of mcsA is subject to CreA-mediated carbon repression. Therefore, McsA can substitute for the loss of CitA activity. Deletion of citA does not affect conidiation or sexual development but results in delayed conidial germination as well as a complete loss of ascospores in fruiting bodies, which can be attributed to loss of meiosis. These defects are suppressed by the creA204 mutation, indicating that McsA activity can substitute for the loss of CitA. A mutation of the putative PTS1-encoding sequence in citA had no effect on carbon source utilization or development but did result in slower colony extension arising from single conidia or ascospores. CitA-green fluorescent protein (GFP) studies showed mitochondrial localization in conidia, ascospores, and hyphae. Peroxisomal localization was not detected. However, a very low and variable detection of punctate GFP fluorescence was sometimes observed in conidia germinated for 5 h when the mitochondrial targeting sequence was deleted.

Download Full-text

A tester system for detecting each of the six base-pair substitutions in Saccharomyces cerevisiae by selecting for an essential cysteine in iso-1-cytochrome c.

Genetics ◽

10.1093/genetics/128.1.59 ◽

1991 ◽

Vol 128 (1) ◽

pp. 59-67

Author(s):

M Hampsey

Keyword(s):

Saccharomyces Cerevisiae ◽

Sequence Analysis ◽

Cytochrome C ◽

Dna Sequence ◽

Base Pair ◽

Carbon Sources ◽

Methyl Methanesulfonate ◽

Low Frequencies ◽

Yeast Strains ◽

Selection Medium

Abstract A collection of isogenic yeast strains that is specifically diagnostic for the six possible base-pair substitutions is described. Each strain contains a single, unique base-pair substitution at the Cys-22 codon of the CYC1 gene, which codes for iso-1-cytochrome c. These mutations encode replacements of the functionally critical Cys-22 and render each strain unable to grow on media containing nonfermentable carbon sources (Cyc-). Specific base-pair substitutions, which restore the Cys-22 codon, can be monitored simply by scoring for reversion to the Cyc+ phenotype. These strains revert spontaneously at very low frequencies and exhibit specific patterns of reversion in response to different mutagens. Only true (CYC1+) revertants were recovered after 7 days on selection medium. The following mutagen specificities were observed: ethyl methanesulfonate and N-methyl-N'-nitro-N-nitrosoguanidine, G.C----A.T; 4-nitroquinoline-1-oxide, G.C----T.A and G.C----A.T; diepoxybutane, A.T----T.A, A.T----G.C and G.C----T.A; 5-azacytidine, G.C----C.G. Methyl methanesulfonate induced all six mutations, albeit at relatively low frequencies, with preference for A.T----T.A and A.T----G.C. Ultraviolet light was the most inefficient mutagen used in this study, consistent with its preference for transition mutations at dipyrimidine sequences reported in other systems. This tester system is valuable as a simple and reliable assay for specific mutations without DNA sequence analysis.

Download Full-text

Saccharomyces cerevisiae JEN1 Promoter Activity Is Inversely Related to Concentration of Repressing Sugar

Applied and Environmental Microbiology ◽

10.1128/aem.70.1.8-17.2004 ◽

2004 ◽

Vol 70 (1) ◽

pp. 8-17 ◽

Cited By ~ 20

Author(s):

Prima Chambers ◽

Aminatu Issaka ◽

Sean P. Palecek

Keyword(s):

Saccharomyces Cerevisiae ◽

Glucose Concentration ◽

Promoter Activity ◽

Fluorescent Protein ◽

Carbon Sources ◽

Regulatory Elements ◽

Dependent Manner ◽

Diauxic Shift ◽

Reporter System ◽

Genomic Expression

ABSTRACT When carbon sources are changed, Saccharomyces cerevisiae transcriptional patterns drastically change. To identify genes whose transcription can be used to quantitatively measure sugar concentrations, we searched genomic expression databases for a set of genes that are highly induced during the diauxic shift, and we used the promoters from these genes to drive expression of green fluorescent protein (GFP). Certain sugars, including glucose, fructose, and mannose, repress the promoter of JEN1, which encodes a lactate-pyruvate transporter, in a dose-dependent manner. Nonrepressing carbon sources include galactose, raffinose, ethanol, lactate, and glycerol. JEN1 promoter activity is a linear function of glucose concentration when organisms are grown at a steady-state glucose concentration below 1 g/liter. JEN1 promoter repression is specific to carbon source; heat or cold shock, osmotic stress, DNA damage, and nitrogen starvation do not significantly affect promoter activity. Activation of the JEN1 promoter requires the Snf1 protein kinase, but multiple regulatory elements most likely combine to provide the linear relationship between JEN1 promoter activity and sugar concentration. Thus, a JEN1 promoter-reporter system appears to provide a good living cell biosensor for the concentration of certain sugars. The JEN1 promoter also permits quantitative regulation of cellular functions not normally controlled by sugar concentrations. For example, a strain expressing FLO1 under control of the JEN1 promoter flocculates at a low glucose concentration.

Download Full-text

Functional expression, quantification and cellular localization of the Hxt2 hexose transporter of Saccharomyces cerevisiae tagged with the green fluorescent protein

Biochemical Journal ◽

10.1042/bj3390299 ◽

1999 ◽

Vol 339 (2) ◽

pp. 299-307 ◽

Cited By ~ 33

Author(s):

Arthur L. KRUCKEBERG ◽

Ling YE ◽

Jan A. BERDEN ◽

Karel van DAM

Keyword(s):

Saccharomyces Cerevisiae ◽

Plasma Membrane ◽

Green Fluorescent Protein ◽

Glucose Transport ◽

Cellular Localization ◽

Fluorescent Protein ◽

Hexose Transporter ◽

High Concentrations ◽

Green Fluorescent

The Hxt2 glucose transport protein of Saccharomyces cerevisiae was genetically fused at its C-terminus with the green fluorescent protein (GFP). The Hxt2-GFP fusion protein is a functional hexose transporter: it restored growth on glucose to a strain bearing null mutations in the hexose transporter genes GAL2 and HXT1 to HXT7. Furthermore, its glucose transport activity in this null strain was not markedly different from that of the wild-type Hxt2 protein. We calculated from the fluorescence level and transport kinetics that induced cells had 1.4×105 Hxt2-GFP molecules per cell, and that the catalytic-centre activity of the Hxt2-GFP molecule in vivo is 53 s-1 at 30 °C. Expression of Hxt2-GFP was induced by growth at low concentrations of glucose. Under inducing conditions the Hxt2-GFP fluorescence was localized to the plasma membrane. In a strain impaired in the fusion of secretory vesicles with the plasma membrane, the fluorescence accumulated in the cytoplasm. When induced cells were treated with high concentrations of glucose, the fluorescence was redistributed to the vacuole within 4 h. When endocytosis was genetically blocked, the fluorescence remained in the plasma membrane after treatment with high concentrations of glucose.

Download Full-text

Recombination of Ty elements in yeast can be induced by a double-strand break.

Genetics ◽

10.1093/genetics/140.1.67 ◽

1995 ◽

Vol 140 (1) ◽

pp. 67-77 ◽

Cited By ~ 1

Author(s):

A Parket ◽

O Inbar ◽

M Kupiec

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

Strand Break ◽

Double Strand Break ◽

The Other ◽

Direct Repeats ◽

Yeast Saccharomyces Cerevisiae ◽

Low Frequencies ◽

Ty Elements ◽

Main Family

Abstract The Ty retrotransposons are the main family of dispersed repeated sequences in the yeast Saccharomyces cerevisiae. These elements are flanked by a pair of long terminal direct repeats (LTRs). Previous experiments have shown that Ty elements recombine at low frequencies, despite the fact that they are present in 30 copies per genome. This frequency is not highly increased by treatments that cause DNA damage, such as UV irradiation. In this study, we show that it is possible to increase the recombination level of a genetically marked Ty by creating a double-strand break in it. This break is repaired by two competing mechanisms: one of them leaves a single LTR in place of the Ty, and the other is a gene conversion event in which the marked Ty is replaced by an ectopically located one. In a strain in which the marked Ty has only one LTR, the double-strand break is repaired by conversion. We have also measured the efficiency of repair and monitored the progression of the cells through the cell-cycle. We found that in the presence of a double-strand break in the marked Ty, a proportion of the cells is unable to resume growth.

Download Full-text

Multicopy FZF1 (SUL1) Suppresses the Sulfite Sensitivity but Not the Glucose Derepression or Aberrant Cell Morphology of a grr1 Mutant of Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/144.2.511 ◽

1996 ◽

Vol 144 (2) ◽

pp. 511-521 ◽

Cited By ~ 3

Author(s):

Dorina Avram ◽

Alan T Bakalinsky

Keyword(s):

Saccharomyces Cerevisiae ◽

Transcription Factor ◽

Glucose Metabolism ◽

Cell Morphology ◽

Glucose Repression ◽

Carbon Sources ◽

Single Copy ◽

Aberrant Cell ◽

Growth Defects ◽

Putative Transcription Factor

Abstract An ssu2 mutation in Sacccharomyces cermisiae, previously shown to cause sulfite sensitivity, was found to be allelic to GRR1, a gene previously implicated in glucose repression. The suppressor rgt1, which suppresses the growth defects of grr1 strains on glucose, did not fully suppress the sensitivity on glucose or nonglucose carbon sources, indicating that it is not strictly linked to a defect in glucose metabolism. Because the Cln1 protein was previously shown to be elevated in grr1 mutants, the effect of CLN1 overexpression on sulfite sensitivity was investigated. Overexpression in GRR1 cells resulted in sulfite sensitivity, suggesting a connection between CLN1 and sulfite metabolism. Multicopy FZF1, a putative transcription factor, was found to suppress the sulfite sensitive phenotype of grr1 strains, but not the glucose derepression or aberrant cell morphology. Multicopy FZF1 was also found to suppress the sensitivity of a number of other unrelated sulfite-sensitive mutants, but not that of ssu1 or met20, implying that FZF1 may act through Ssulp and Met20p. Disruption of FZF1 resulted in sulfite sensitivity when the construct was introduced in single copy at the FZF1 locus in a GRR1 strain, providing evidence that FZF1 is involved in sulfite metabolism.

Download Full-text

Maintenance of Mitochondrial Morphology Is Linked to Maintenance of the Mitochondrial Genome in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/162.3.1147 ◽

2002 ◽

Vol 162 (3) ◽

pp. 1147-1156 ◽

Cited By ~ 1

Author(s):

Theodor Hanekamp ◽

Mary K Thorsness ◽

Indrani Rebbapragada ◽

Elizabeth M Fisher ◽

Corrine Seebart ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Growth Rate ◽

Mitochondrial Dna ◽

Carbon Sources ◽

Mitochondrial Morphology ◽

Yeast Saccharomyces Cerevisiae ◽

Slow Growth Rate ◽

Dna Migration ◽

Mitochondrial Dna Stability ◽

Extragenic Suppressors

Abstract In the yeast Saccharomyces cerevisiae, certain mutant alleles of YME4, YME6, and MDM10 cause an increased rate of mitochondrial DNA migration to the nucleus, carbon-source-dependent alterations in mitochondrial morphology, and increased rates of mitochondrial DNA loss. While single mutants grow on media requiring mitochondrial respiration, any pairwise combination of these mutations causes a respiratory-deficient phenotype. This double-mutant phenotype allowed cloning of YME6, which is identical to MMM1 and encodes an outer mitochondrial membrane protein essential for maintaining normal mitochondrial morphology. Yeast strains bearing null mutations of MMM1 have altered mitochondrial morphology and a slow growth rate on all carbon sources and quantitatively lack mitochondrial DNA. Extragenic suppressors of MMM1 deletion mutants partially restore mitochondrial morphology to the wild-type state and have a corresponding increase in growth rate and mitochondrial DNA stability. A dominant suppressor also suppresses the phenotypes caused by a point mutation in MMM1, as well as by specific mutations in YME4 and MDM10.

Download Full-text