Oxygen and haem regulate the synthesis of peroxisomal proteins: catalase A, acyl-CoA oxidase and Pex1p in the yeast Saccharomyces cerevisiae; the regulation of these proteins by oxygen is not mediated by haem

Saccharomyces cerevisiae genes related to respiration are typically controlled by oxygen and haem. Usually the regulation by these factors is co-ordinated; haem is indicated as the oxygen sensor. However, the responsiveness of peroxisome functions to these regulatory factors is poorly understood. The expression of CTA1, POX1 and PEX1 genes encoding the peroxisomal proteins catalase A, acyl-CoA oxidase and Pex1p peroxin respectively was studied under various conditions: in anaerobiosis, in the absence of haem and in respiratory incompetence caused by the lack of a mitochondrial genome (ρ0). The influence of haem deficiency or ρ0 on peroxisomal morphology was also investigated. Respiratory incompetence has no effect on the expression of CTA1 and POX1, whereas in the absence of haem their expression is markedly decreased. The synthesis of Pex1p is decreased in ρ0 cells and is decreased even more in haem-deficient cells. Nevertheless, peroxisomal morphology in both these types of cell does not differ significantly from the morphology of peroxisomes in wild-type cells. The down-regulating effect of anoxia on the expression of CTA1 and POX1 is even stronger than the effect of haem deficiency and is not reversed by the addition of exogenous haem or the presence of endogenous haem. Moreover, neither of these genes responds to the known haem-controlled transcriptional factor Hap1p. In contrast with the other two genes studied, PEX1 is up-regulated in anaerobiosis. The existence of one or more novel mechanisms of regulation of peroxisomal genes by haem and oxygen, different from those already known in S. cerevisiae, is postulated.

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Rsp5p, a New Link between the Actin Cytoskeleton and Endocytosis in the Yeast Saccharomyces cerevisiae

Molecular and Cellular Biology ◽

10.1128/mcb.22.20.6946-6958.2002 ◽

2002 ◽

Vol 22 (20) ◽

pp. 6946-6948 ◽

Cited By ~ 42

Author(s):

Joanna Kamińska ◽

Beata Gajewska ◽

Anita K. Hopper ◽

Teresa ˙Zołądek

Keyword(s):

Saccharomyces Cerevisiae ◽

Actin Cytoskeleton ◽

Cytoskeletal Proteins ◽

Wild Type ◽

Yeast Saccharomyces Cerevisiae ◽

Ww Domains ◽

Ubiquitin Protein Ligase ◽

Growth Defects ◽

Genes Encoding ◽

Cytoskeleton Dynamics

ABSTRACT Rsp5p is an ubiquitin-protein ligase of Saccharomyces cerevisiae that has been implicated in numerous processes including transcription, mitochondrial inheritance, and endocytosis. Rsp5p functions at multiple steps of endocytosis, including ubiquitination of substrates and other undefined steps. We propose that one of the roles of Rsp5p in endocytosis involves maintenance and remodeling of the actin cytoskeleton. We report the following. (i) There are genetic interactions between rsp5 and several mutant genes encoding actin cytoskeletal proteins. rsp5 arp2, rsp5 end3, and rsp5 sla2 double mutants all show synthetic growth defects. Overexpressed wild-type RSP5 or mutant rsp5 genes with lesions of some WW domains suppress growth defects of arp2 and end3 cells. The defects in endocytosis, actin cytoskeleton, and morphology of arp2 are also suppressed. (ii) Rsp5p and Sla2p colocalize in abnormal F-actin-containing clumps in arp2 and pan1 mutants. Immunoprecipitation experiments confirmed that Rsp5p and Act1p colocalize in pan1 mutants. (iii) Rsp5p and Sla2p coimmunoprecipitate and partially colocalize to punctate structures in wild-type cells. These studies provide the first evidence for an interaction of an actin cytoskeleton protein with Rsp5p. (iv) rsp5-w1 mutants are resistant to latrunculin A, a drug that sequesters actin monomers and depolymerizes actin filaments, consistent with the fact that Rsp5p is involved in actin cytoskeleton dynamics.

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Depletion of H2A-H2B Dimers in Saccharomyces cerevisiae Triggers Meiotic Arrest by Reducing IME1 Expression and Activating the BUB2-Dependen Branch of the Spindle Checkpoint

Genetics ◽

10.1093/genetics/164.4.1333 ◽

2003 ◽

Vol 164 (4) ◽

pp. 1333-1344

Author(s):

Sean E Hanlon ◽

David N Norris ◽

Andrew K Vershon

Keyword(s):

Saccharomyces Cerevisiae ◽

Spindle Checkpoint ◽

The Other ◽

Histone H2a ◽

Wild Type ◽

Meiotic Arrest ◽

Yeast Saccharomyces Cerevisiae ◽

Chromosomal Alterations ◽

Checkpoint Pathway ◽

Failure To Progress

Abstract In the yeast Saccharomyces cerevisiae, diploid strains carrying homozygous hta1-htb1Δ mutations express histone H2A-H2B dimers at a lower level than do wild-type cells. Although this mutation has only minor effects on mitotic growth, it causes an arrest in sporulation prior to the first meiotic division. In this report, we show that the hta1-htb1Δ mutant exhibits reduced expression of early and middle-sporulation-specific genes and that the meiotic arrest of the hta1-htb1Δ mutant can be partially bypassed by overexpression of IME1. Additionally, deletions of BUB2 or BFA1, components of one branch of the spindle checkpoint pathway, bypass the meiotic arrest. Mutations in the other branch of the pathway or in the pachytene checkpoint are unable to suppress the meiotic block. These observations indicate that depletion of the H2A-H2B dimer blocks sporulation by at least two mechanisms: disruption of the expression of meiotic regulatory genes and activation of the spindle checkpoint. Our results show that the failure to progress through the meiotic pathway is not the result of global chromosomal alterations but that specific aspects of meiosis are sensitive to depletion of the H2A-H2B dimer.

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MAPPING AND GENE CONVERSION STUDIES WITH THE STRUCTURAL GENE FOR ISO-1-CYTOCHROME C IN YEAST

Genetics ◽

10.1093/genetics/81.4.615 ◽

1975 ◽

Vol 81 (4) ◽

pp. 615-629

Author(s):

Christopher W Lawrence ◽

Fred Sherman ◽

Mary Jackson ◽

Richard A Gilmore

Keyword(s):

Saccharomyces Cerevisiae ◽

Gene Conversion ◽

The Other ◽

Crossing Over ◽

Wild Type ◽

Chromosome X ◽

Tetrad Analysis ◽

Yeast Saccharomyces Cerevisiae ◽

Distal Marker ◽

The Right

ABSTRACT We have investigated the order of the four genes cyc1, rad7, SUP4, and cdc8 which form a tightly linked cluster on the right arm of chromosome X in the yeast Saccharomyces cerevisiae. Crossing over and coconversion data from tetrad analysis established the gene order to be centromere–cyc1–rad7–SUP4. Also cdc8 appeared to be distal to SUP4 on the basis of crossovers that were associated with conversion of SUP4. The frequencies of recombination and the occurrence of coconversions suggest that these four genes are contiguous or at least nearly so. Gene-conversion frequencies for several cyc1 alleles were studied, including cyc1–1, a deletion of the whole gene that extends into the rad7 locus. The cyc1–1 deletion was found to be capable of conversion, though at a frequency some fivefold less than the other alleles studied, and both 3:1 and 1:3 events were detected. In general 1:3 and 3:1 conversion events were equally frequent at all loci studied, and approximately 50% of conversions were accompanied by reciprocal recombination for flanking markers. The orientation of the cyc1 gene could not be clearly deduced from the behavior of the distal marker SUP4 in wild-type recombinants that arose from diploids heteroallelic for cyc1 mutations.

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Nonrecombinant meiosis I nondisjunction in Saccharomyces cerevisiae induced by tRNA ochre suppressors.

Genetics ◽

10.1093/genetics/123.1.81 ◽

1989 ◽

Vol 123 (1) ◽

pp. 81-95 ◽

Cited By ~ 1

Author(s):

E J Louis ◽

J E Haber

Keyword(s):

Saccharomyces Cerevisiae ◽

Mitotic Chromosome ◽

Stop Codon ◽

Fold Increase ◽

Wild Type ◽

Yeast Saccharomyces Cerevisiae ◽

Nonsense Mutations ◽

Chromosome Iii ◽

Meiosis I ◽

Chromosome Nondisjunction

Abstract The presence of the tRNA ochre suppressors SUP11 and SUP5 is found to induce meiosis I nondisjunction in the yeast Saccharomyces cerevisiae. The induction increases with increasing dosage of the suppressor and decreases in the presence of an antisuppressor. The effect is independent of the chromosomal location of SUP11. Each of five different chromosomes monitored exhibited nondisjunction at frequencies of 0.1%-1.1% of random spores, which is a 16-160-fold increase over wild-type levels. Increased nondisjunction is reflected by a marked increase in tetrads with two and zero viable spores. In the case of chromosome III, for which a 50-cM map interval was monitored, the resulting disomes are all in the parental nonrecombinant configuration. Recombination along chromosome III appears normal both in meioses that have no nondisjunction and in meioses for which there was nondisjunction of another chromosome. We propose that a proportion of one or more proteins involved in chromosome pairing, recombination or segregation are aberrant due to translational read-through of the normal ochre stop codon. Hygromycin B, an antibiotic that can suppress nonsense mutations via translational read-through, also induces nonrecombinant meiosis I nondisjunction. Increases in mistranslation, therefore, increase the production of aneuploids during meiosis. There was no observable effect of SUP11 on mitotic chromosome nondisjunction; however some disomes caused SUP11 ade2-ochre strains to appear white or red, instead of pink.

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Underproduction of the Largest Subunit of RNA Polymerase II Causes Temperature Sensitivity, Slow Growth, and Inositol Auxotrophy in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/142.3.737 ◽

1996 ◽

Vol 142 (3) ◽

pp. 737-747 ◽

Cited By ~ 7

Author(s):

Jacques Archambault ◽

David B Jansma ◽

James D Friesen

Keyword(s):

Saccharomyces Cerevisiae ◽

Steady State ◽

Rna Polymerase ◽

Rna Polymerase Ii ◽

Reporter Gene ◽

Growth Medium ◽

Temperature Sensitivity ◽

Slow Growth ◽

Yeast Saccharomyces Cerevisiae ◽

Genes Encoding

Abstract In the yeast Saccharomyces cerevisiae, mutations in genes encoding subunits of RNA polymerase II (RNAPII) often give rise to a set of pleiotropic phenotypes that includes temperature sensitivity, slow growth and inositol auxotrophy. In this study, we show that these phenotypes can be brought about by a reduction in the intracellular concentration of RNAPII. Underproduction of RNAPII was achieved by expressing the gene (RPO21), encoding the largest subunit of the enzyme, from the LEU2 promoter or a weaker derivative of it, two promoters that can be repressed by the addition of leucine to the growth medium. We found that cells that underproduced RPO21 were unable to derepress fully the expression of a reporter gene under the control of the INO1 UAS. Our results indicate that temperature sensitivity, slow growth and inositol auxotrophy is a set of phenotypes that can be caused by lowering the steady-state amount of RNAPII; these results also lead to the prediction that some of the previously identified RNAPII mutations that confer this same set of phenotypes affect the assembly/stability of the enzyme. We propose a model to explain the hypersensitivity of INO1 transcription to mutations that affect components of the RNAPII transcriptional machinery.

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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.

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act Operon Control of Developmental Gene Expression in Myxococcus xanthus

Journal of Bacteriology ◽

10.1128/jb.184.4.1172-1179.2002 ◽

2002 ◽

Vol 184 (4) ◽

pp. 1172-1179 ◽

Cited By ~ 32

Author(s):

Thomas M. A. Gronewold ◽

Dale Kaiser

Keyword(s):

Fruiting Body ◽

Myxococcus Xanthus ◽

The Other ◽

Loss Of Function ◽

Wild Type ◽

Developmental Gene ◽

Developmental Gene Expression ◽

Mutant Strains ◽

Genes Encoding ◽

Signal Production

ABSTRACT Cell-bound C-signal guides the building of a fruiting body and triggers the differentiation of myxospores. Earlier work has shown that transcription of the csgA gene, which encodes the C-signal, is directed by four genes of the act operon. To see how expression of the genes encoding components of the aggregation and sporulation processes depends on C-signaling, mutants with loss-of-function mutations in each of the act genes were investigated. These mutations were found to have no effect on genes that are normally expressed up to 3 h into development and are C-signal independent. Neither the time of first expression nor the rate of expression increase was changed in actA, actB, actC, or actD mutant strains. Also, there was no effect on A-signal production, which normally starts before 3 h. By contrast, the null act mutants have striking defects in C-signal production. These mutations changed the expression of four gene reporters that are related to aggregation and sporulation and are expressed at 6 h or later in development. The actA and actB null mutations substantially decreased the expression of all these reporters. The other act null mutations caused either premature expression to wild-type levels (actC) or delayed expression (actD), which ultimately rose to wild-type levels. The pattern of effects on these reporters shows how the C-signal differentially regulates the steps that together build a fruiting body and differentiate spores within it.

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Spindle dynamics and cell cycle regulation of dynein in the budding yeast, Saccharomyces cerevisiae.

The Journal of Cell Biology ◽

10.1083/jcb.130.3.687 ◽

1995 ◽

Vol 130 (3) ◽

pp. 687-700 ◽

Cited By ~ 272

Author(s):

E Yeh ◽

R V Skibbens ◽

J W Cheng ◽

E D Salmon ◽

K Bloom

Keyword(s):

Saccharomyces Cerevisiae ◽

Nuclear Translocation ◽

Spindle Pole ◽

Cell Cortex ◽

Wild Type ◽

Immunofluorescent Localization ◽

Yeast Saccharomyces Cerevisiae ◽

Spindle Dynamics ◽

Spindle Elongation ◽

Anaphase B

We have used time-lapse digital- and video-enhanced differential interference contrast (DE-DIC, VE-DIC) microscopy to study the role of dynein in spindle and nuclear dynamics in the yeast Saccharomyces cerevisiae. The real-time analysis reveals six stages in the spindle cycle. Anaphase B onset appears marked by a rapid phase of spindle elongation, simultaneous with nuclear migration into the daughter cell. The onset and kinetics of rapid spindle elongation are identical in wild type and dynein mutants. In the absence of dynein the nucleus does not migrate as close to the neck as in wild-type cells and initial spindle elongation is confined primarily to the mother cell. Rapid oscillations of the elongating spindle between the mother and bud are observed in wild-type cells, followed by a slower growth phase until the spindle reaches its maximal length. This stage is protracted in the dynein mutants and devoid of oscillatory motion. Thus dynein is required for rapid penetration of the nucleus into the bud and anaphase B spindle dynamics. Genetic analysis reveals that in the absence of a functional central spindle (ndcl), dynein is essential for chromosome movement into the bud. Immunofluorescent localization of dynein-beta-galactosidase fusion proteins reveals that dynein is associated with spindle pole bodies and the cell cortex: with spindle pole body localization dependent on intact microtubules. A kinetic analysis of nuclear movement also revealed that cytokinesis is delayed until nuclear translocation is completed, indicative of a surveillance pathway monitoring nuclear transit into the bud.

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Topoisomerase I involvement in illegitimate recombination in Saccharomyces cerevisiae.

Molecular and Cellular Biology ◽

10.1128/mcb.16.4.1805 ◽

1996 ◽

Vol 16 (4) ◽

pp. 1805-1812 ◽

Cited By ~ 58

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.

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

Canadian Journal of Microbiology ◽

10.1139/m78-107 ◽

1978 ◽

Vol 24 (6) ◽

pp. 637-642 ◽

Cited By ~ 6

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.

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