The fission yeast bromodomain protein Bdf2 is required for growth of cells with circular chromosomes

2021 ◽  
Author(s):  
Misaki Yasuda ◽  
Ahmed G K Habib ◽  
Kanako Sugiura ◽  
Hossain Mohammad Shamim ◽  
Masaru Ueno
Keyword(s):  
Fission Yeast ◽  
High Temperatures ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
M Phase ◽  
Ts Mutant ◽  
Synthetically Lethal ◽  
Circular Chromosomes ◽  
Synthetic Growth

Abstract Circular chromosomes have frequently been observed in tumors of mesenchymal origin. In the fission yeast Schizosaccharomyces pombe, deletion of pot1+ results in rapid telomere loss, and the resulting survivors have circular chromosomes. Fission yeast has two bromodomains and extra-terminal (BET) proteins, Bdf1 and Bdf2; both are required for maintaining acetylated histones. Here, we found that bdf2, but not bdf1, was synthetically lethal with pot1. We also obtained a temperature-sensitive bdf2-ts mutant, which can grow at high temperatures but becomes camptothecin sensitive. This suggests that Bdf2 is defective at high temperatures. The cell cycle of the pot1 bdf2-ts mutant was delayed in the G2 and/or M phase at a semi-permissive temperature. Furthermore, a temperature-sensitive mutant of mst1, which encodes histone acetyltransferase, showed a synthetic growth defect with a pot1 disruptant at a semi-permissive temperature. Our results suggest that Bdf2 and Mst1 are required for the growth of cells with circular chromosomes.

scholarly journals Characterization of Schizosaccharomyces pombe mcm7+ and cdc23+ (MCM10) and Interactions With Replication Checkpoints

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 471-486 ◽  
Author(s):  
Debbie T Liang ◽  
Susan L Forsburg
Keyword(s):  
Fission Yeast ◽  
S Phase ◽  
The Other ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
2C Dna Content ◽  
Mcm Proteins ◽  
Sensitive Allele ◽  
Synthetically Lethal ◽  
Yeast Homolog

Abstract MCM proteins are required for the proper regulation of DNA replication. We cloned fission yeast mcm7+ and showed it is essential for viability; spores lacking mcm7+ begin S phase later than wild-type cells and arrest with an apparent 2C DNA content. We isolated a novel temperature-sensitive allele, mcm7-98, and also characterized two temperature-sensitive alleles of the fission yeast homolog of MCM10, cdc23+. mcm7-98 and both cdc23ts alleles arrest with damaged chromosomes and an S phase delay. We find that mcm7-98 is synthetically lethal with the other mcmts mutants but does not interact genetically with either cdc23ts allele. However, cdc23-M36 interacts with mcm4ts. Unlike other mcm mutants or cdc23, mcm7-98 is synthetically lethal with checkpoint mutants Δcds1, Δchk1, or Δrad3, suggesting chromosomal defects even at permissive temperature. Mcm7p is a nuclear protein throughout the cell cycle, and its localization is dependent on the other MCM proteins. Our data suggest that the Mcm3p-Mcm5p dimer interacts with the Mcm4p-Mcm6p-Mcm7p core complex through Mcm7p.

scholarly journals Suppressors of a Saccharomyces cerevisiae pkc1 mutation identify alleles of the phosphatase gene PTC1 and of a novel gene encoding a putative basic leucine zipper protein.

Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1275-1285 ◽  
Author(s):  
K N Huang ◽  
L S Symington
Keyword(s):  
Protein Kinase ◽  
Leucine Zipper ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Gene Encoding ◽  
Basic Leucine Zipper ◽  
Mapk Cascades ◽  
Synthetically Lethal

Abstract The PKC1 gene product, protein kinase C, regulates a mitogen-activated protein kinase (MAPK) cascade, which is implicated in cell wall metabolism. Previously, we identified the pkc1-4 allele in a screen for mutants with increased rates of recombination, indicating that PKC1 may also regulate DNA metabolism. The pkc1-4 allele also conferred a temperature-sensitive (ts) growth defect. Extragenic suppressors were isolated that suppress both the ts and hyperrecombination phenotypes conferred by the pkc1-4 mutation. Eight of these suppressors for into two complementation groups, designated KCS1 and KCS2. KCS1 was cloned and found to encode a novel protein with homology to the basic leucine zipper family of transcription factors. KCS2 is allelic with PTC1, a previously identified type 2C serine/threonine protein phosphatase. Although mutation of either KCS1 or PTC1 causes little apparent phenotype, the kcs1 delta ptc1 delta double mutant fails to grow at 30 degrees. Furthermore, the ptc1 deletion mutation is synthetically lethal in combination with a mutation in MPK1, which encodes a MAPK homologue proposed to act in the PKC1 pathway. Because PTC1 was initially isolated as a component of the Hog1p MAPK pathway, it appears that these two MAPK cascades share a common regulatory feature.

scholarly journals Fission yeast Dss1 associates with the proteasome and is required for efficient ubiquitin-dependent proteolysis

2005 ◽  
Vol 393 (1) ◽  
pp. 303-309 ◽  
Author(s):  
Lyne Jossé ◽  
Margaret E. Harley ◽  
Isabel M. S. Pires ◽  
David A. Hughes
Keyword(s):  
Fission Yeast ◽  
Physiological Role ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Growth Defects ◽  
Tumour Suppressor Protein ◽  
Low Concentrations ◽  
Acid Analogue ◽  
Evolutionarily Conserved ◽  
Related Proteins

Human DSS1 associates with BRCA2, a tumour suppressor protein required for efficient recombinational DNA repair, but the biochemical function of DSS1 is not known. Orthologues of DSS1 are found in organisms such as budding yeast and fission yeast that do not have BRCA2-related proteins, indicating that DSS1 has a physiological role independent of BRCA2. The DSS1 orthologue in Saccharomyces cerevisiae has been shown to associate with the 26 S proteasome and, in the present paper, we report that in the distantly related fission yeast Schizosaccharomyces pombe, Dss1 associates with the 19 S RP (regulatory particle) of the 26 S proteasome. A role for S. pombe Dss1 in proteasome function is supported by three lines of evidence. First, overexpression of two components of the 19 S RP, namely Pad1/Rpn11 and Mts3/Rpn12, rescued the temperature-sensitive growth defect of the dss1 mutant. Secondly, the dss1 mutant showed phenotypes indicative of a defect in proteasome function: growth of the dss1 mutant was inhibited by low concentrations of L-canavanine, an amino acid analogue, and cells of the dss1 mutant accumulated high molecular mass poly-ubiquitylated proteins. Thirdly, synthetic growth defects were found when the dss1 mutation was combined with mutations in other proteasome subunit genes. These findings show that DSS1 has an evolutionarily conserved role as a regulator of proteasome function and suggest that DSS1 may provide a link between BRCA2 and ubiquitin-mediated proteolysis in human cells.

scholarly journals The Ccr4-Not Complex and yTAF1 (yTafII130p/yTafII145p) Show Physical and Functional Interactions

2002 ◽  
Vol 22 (19) ◽  
pp. 6735-6749 ◽  
Author(s):  
Cécile Deluen ◽  
Nicole James ◽  
Laurent Maillet ◽  
Miguel Molinete ◽  
Grégory Theiler ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Tata Binding Protein ◽  
Molecular Evidence ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Global Regulator ◽  
Functional Interactions ◽  
Terminal Domain ◽  
Synthetically Lethal ◽  
Promoter Dna

ABSTRACT The Saccharomyces cerevisiae Ccr4-Not complex is a global regulator of transcription that is thought to regulate TATA binding protein (TBP) function at certain promoters specifically. In this paper, we show interactions between the essential domain of Not1p, which interacts with Not4p and Not5p, and the N-terminal domain of yTAF1. We isolated a temperature-sensitive nonsense allele of TAF1, taf1-4, which is synthetically lethal at the permissive temperature when combined with not4 and not5 mutants and which produces high levels of a C-terminally truncated yTAF1 derivative. Overexpression of C-terminally truncated yTAF1 is toxic in not4 or not5 mutants, whereas overexpression of full-length yTAF1 suppresses not4. Furthermore, mutations in the autoinhibitory N-terminal TAND domain of yTAF1 suppress not5, and the overexpression of similar mutants does not suppress not4. We find that, like Not5p, yTAF1 acts as a repressor of stress response element-dependent transcription. Finally, we have evidence for stress-regulated occupancy of promoter DNA by Not5p and for Not5p-dependent regulation of yTAF1 association with promoter DNA. Taken together with our finding that Not1p copurifies with glutathione S-transferase-yTaf1 in large complexes, these results provide the first molecular evidence that the Ccr4-Not complex might interact with yTAF1 to regulate its association at promoters, a function that might in turn regulate the autoinhibitory N-terminal domain of yTAF1.

scholarly journals A Fourth Component of the Fission Yeast γ-Tubulin Complex, Alp16, Is Required for Cytoplasmic Microtubule Integrity and Becomes Indispensable When γ-Tubulin Function Is Compromised

2002 ◽  
Vol 13 (7) ◽  
pp. 2360-2373 ◽  
Author(s):  
Akiko Fujita ◽  
Leah Vardy ◽  
Miguel Angel Garcia ◽  
Takashi Toda
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Temperature Sensitive ◽  
Microtubule Organizing Center ◽  
Cytoplasmic Microtubule ◽  
Multicopy Suppressor ◽  
Large Complex ◽  
Synthetically Lethal ◽  
And Function

γ-Tubulin functions as a multiprotein complex, called the γ-tubulin complex (γ-TuC), and composes the microtubule organizing center (MTOC). Fission yeast Alp4 and Alp6 are homologues of two conserved γ-TuC proteins, hGCP2 and hGCP3, respectively. We isolated a novel gene, alp16 + , as a multicopy suppressor of temperature-sensitive alp6-719mutants. alp16 + encodes a 759-amino-acid protein with two conserved regions found in all other members of γ-TuC components. In addition, Alp16 contains an additional motif, which shows homology to hGCP6/Xgrip210. Gene disruption shows that alp16 + is not essential for cell viability. However, alp16 deletion displays abnormally long cytoplasmic microtubules, which curve around the cell tip. Furthermore, alp16-deleted mutants are hypersensitive to microtubule-depolymerizing drugs and synthetically lethal with either temperature-sensitive alp4-225,alp4-1891, or alp6-719 mutants. Overproduction of Alp16 is lethal, with defective phenotypes very similar to loss of Alp4 or Alp6. Alp16 localizes to the spindle pole body throughout the cell cycle and to the equatorial MTOC at postanaphase. Alp16 coimmunoprecipitates with γ-tubulin and cosediments with the γ-TuC in a large complex (>20 S). Alp16 is, however, not required for the formation of this large complex. We discuss evolutional conservation and divergence of structure and function of the γ-TuC between yeast and higher eukaryotes.

scholarly journals Targeting of the yeast plasma membrane [H+]ATPase: a novel gene AST1 prevents mislocalization of mutant ATPase to the vacuole.

1995 ◽  
Vol 128 (1) ◽  
pp. 39-49 ◽  
Author(s):  
A Chang ◽  
G R Fink
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Growth Defect ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Plasma Membrane Atpase ◽  
Novel Gene ◽  
Multicopy Suppressors ◽  
Proteinase A ◽  
Synthetic Growth

We have characterized a class of mutations in PMA1, (encoding plasma membrane ATPase) that is ideal for the analysis of membrane targeting in Saccharomyces cerevisiae. This class of pma1 mutants undergoes growth arrest at the restrictive temperature because newly synthesized ATPase fails to be targeted to the cell surface. Instead, mutant ATPase is delivered to the vacuole, where it is degraded. Delivery to the vacuole occurs without previous arrival at the plasma membrane because degradation of mutant ATPase is not prevented when internalization from the cell surface is blocked. Disruption of PEP4, encoding vacuolar proteinase A, blocks ATPase degradation, but fails to restore growth because the ATPase is still improperly targeted. One of these pma1 mutants was used to select multicopy suppressors that would permit growth at the nonpermissive temperature. A novel gene, AST1, identified by this selection, suppresses several pma1 alleles defective for targeting. The basis for suppression is that multicopy AST1 causes rerouting of mutant ATPase from the vacuole to the cell surface. pma1 mutants deleted for AST1 have a synthetic growth defect at the permissive temperature, providing genetic evidence for interaction between AST1 and PMA1. Ast1 is a cytoplasmic protein that associates with membranes, and is localized to multiple compartments, including the plasma membrane. The identification of AST1 homologues suggests that Ast1 belongs to a novel family of proteins that participates in membrane traffic.

scholarly journals Bni1p Regulates Microtubule-Dependent Nuclear Migration through the Actin Cytoskeleton in Saccharomyces cerevisiae

1999 ◽  
Vol 19 (12) ◽  
pp. 8016-8027 ◽  
Author(s):  
Takeshi Fujiwara ◽  
Kazuma Tanaka ◽  
Eiji Inoue ◽  
Mitsuhiro Kikyo ◽  
Yoshimi Takai
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Actin Cytoskeleton ◽  
Nuclear Migration ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Cortical Actin ◽  
Synthetic Lethal ◽  
Downstream Target ◽  
Synthetically Lethal ◽  
Mother Cells

ABSTRACT The RHO1 gene encodes a yeast homolog of the mammalian RhoA protein. Rho1p is localized to the growth sites and is required for bud formation. We have recently shown that Bni1p is one of the potential downstream target molecules of Rho1p. The BNI1gene is implicated in cytokinesis and the establishment of cell polarity in Saccharomyces cerevisiae but is not essential for cell viability. In this study, we screened for mutations that were synthetically lethal in combination with a bni1 mutation and isolated two genes. They were the previously identifiedPAC1 and NIP100 genes, both of which are implicated in nuclear migration in S. cerevisiae. Pac1p is a homolog of human LIS1, which is required for brain development, whereas Nip100p is a homolog of rat p150Glued, a component of the dynein-activated dynactin complex. Disruption ofBNI1 in either the pac1 or nip100mutant resulted in an enhanced defect in nuclear migration, leading to the formation of binucleate mother cells. The arp1 bni1mutant showed a synthetic lethal phenotype while the cin8 bni1 mutant did not, suggesting that Bni1p functions in a kinesin pathway but not in the dynein pathway. Cells of the pac1 bni1 and nip100 bni1 mutants exhibited a random distribution of cortical actin patches. Cells of the pac1 act1-4 mutant showed temperature-sensitive growth and a nuclear migration defect. These results indicate that Bni1p regulates microtubule-dependent nuclear migration through the actin cytoskeleton. Bni1p lacking the Rho-binding region did not suppress the pac1 bni1 growth defect, suggesting a requirement for the Rho1p-Bni1p interaction in microtubule function.

scholarly journals Functional interaction of cytosolic hsp70 and a DnaJ-related protein, Ydj1p, in protein translocation in vivo.

1996 ◽  
Vol 16 (8) ◽  
pp. 4378-4386 ◽  
Author(s):  
J Becker ◽  
W Walter ◽  
W Yan ◽  
E A Craig
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Translocation ◽  
Genetic Interaction ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Alpha Factor ◽  
Synthetically Lethal ◽  
Shock Proteins ◽  
Related Proteins

In order to analyze the in vivo role of the SSA class of cytosolic 70-kDa heat shock proteins (hsps) of Saccharomyces cerevisiae, we isolated a temperature-sensitive mutant of SSA1. The effect of a shift of mutant cells (ssa1ts ssa2 ssa3 ssa4) from the permissive temperature of 23 degrees C to the nonpermissive temperature of 37 degrees C on the processing of several precursor proteins translocated into the endoplasmic reticulum or mitochondria was assessed. Of three mitochondrial proteins tested, the processing of only one, the beta subunit of the F1F0 ATPase, was dramatically affected. Of six proteins destined for the endoplasmic reticulum, the translocation of only prepro-alpha-factor and proteinase A was inhibited. The processing of prepro-alpha-factor was inhibited within 2 min of the shift to 37 degrees C, suggesting a direct effect of the hsp70 defect on translocation. More than 50% of radiolabeled alpha-factor accumulated in the precursor form, with the remainder rapidly reaching the mature form. However, the translocation block was complete, as the precursor form could not be chased through the translocation pathway. Since DnaJ-related proteins are known to interact with hsp70s and strains containing conditional mutations in a dnaJ-related gene, YDJ1, are defective in translocation of prepro-alpha-factor, we looked for a genetic interaction between SSA genes and YDJ1 in vivo. We found that a deletion mutation of YDJ1 was synthetically lethal in a ssa1ts ssa2 ssa3 ssa4 background. In addition, a strain containing a single functional SSA gene, SSA1, and a deletion of YDJ1 accumulated the precursor form of alpha-factor. However, no genetic interaction was observed between a YDJ1 mutation and mutations in the SSB genes, which encode a second class of cytosolic hsp70 chaperones. These results are consistent with SSA proteins and Ydj1p acting together in the translocation process.

scholarly journals Characterization of high frequency of recombination strains selected by integrative suppression of F’lac in dnaA, gyrA and gyrB temperature sensitive mutants

2017 ◽  
Vol 90 (1) ◽  
Author(s):  
Eugenio A. Debbia ◽  
Anna Marchese
Keyword(s):  
High Frequency ◽  
Great Majority ◽  
Dna Gyrase ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Cellular Functions ◽  
Ts Mutant ◽  
Time Kill ◽  
Derivatives Of

Integration of F’lac plasmid into chromosome of both gyrA(Ts) and gyrB(Ts) cells phenotypically suppress the thermosensitive mutations of the DNA gyrase enzymes. As the comparative strains isolated from dnaA(Ts), these high frequency of recombination (Hfr) derivatives were able to transfer chromosomal markers to recipient strains, showed a growth rate of about 60 min, and developed filamentous forms when incubated at the temperature of 43°C. Conversely to dnaA(Ts) Hfr selected isolates, the great majority of Hfr derivative of gyrase mutants resulted resistant to acridine orange and rifampin. Time-kill experiments carried out at the non-permissive temperature also revealed that nalidixic acid has no antibacterial activity on these Hfr strains while derivatives of dnaA(Ts) mutant, as well as the control strain HfrH, were strongly inhibited by this drug. Therefore F plasmid induced duplication of chromosome in the mutants even if the DNA gyrase enzymes are not working. Of a certain interest is that these bacteria exhibit physiological perturbations that affect the main cellular functions, however, they do not appear essential for the survival of the strains.

scholarly journals Sec3p is involved in secretion and morphogenesis in Saccharomyces cerevisiae.

1997 ◽  
Vol 8 (4) ◽  
pp. 647-662 ◽  
Author(s):  
F P Finger ◽  
P Novick
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Temperature Sensitive ◽  
Synthetic Lethal ◽  
Growth Defects ◽  
Actin Structure ◽  
Synthetically Lethal ◽  
Bud Site ◽  
Slow Growing ◽  
Late Stages ◽  
Synthetic Growth

Two new temperature-sensitive alleles of SEC3, 1 of 10 late-acting SEC genes required for targeting or fusion of post-Golgi secretory vesicles to the plasma membrane in Saccharomyces cerevisiae, were isolated in a screen for temperature-sensitive secretory mutants that are synthetically lethal with sec4-8. The new sec3 alleles affect early as well as late stages of secretion. Cloning and sequencing of the SEC3 gene revealed that it is identical to profilin synthetic lethal 1 (PSL1). The SEC3 gene is not essential because cells depleted of Sec3p are viable although slow growing and temperature sensitive. All of the sec3 alleles genetically interact with a profilin mutation, pfy1-111. The SEC3 gene in high copy suppresses pfy1-111 and sec5-24 and causes synthetic growth defects with ypt1, sec8-9, sec10-2, and sec15-1. Actin structure is only perturbed in conditions of chronic loss of Sec3p function, implying that Sec3p does not directly regulate actin. All alleles of sec3 cause bud site selection defects in homozygous diploids, as do sec4-8 and sec9-4. This suggests that SEC gene products are involved in determining the bud site and is consistent with a role for Sec3p in determining the correct site of exocytosis.

Sign in / Sign up

Export Citation Format

Share Document