scholarly journals Roles of Hsl1p and Hsl7p in Swe1p Degradation: beyond Septin Tethering

2012 ◽  
Vol 11 (12) ◽  
pp. 1496-1502 ◽  
Author(s):  
Kindra King ◽  
Michelle Jin ◽  
Daniel Lew
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Nuclear Division ◽  
Cell Division Cycle ◽  
Cyclin Dependent Kinase ◽  
Bud Formation ◽  
Content Type ◽  
Cell Cycle Delay ◽  
Bud Neck

ABSTRACT The morphogenesis checkpoint in Saccharomyces cerevisiae couples bud formation to the cell division cycle by delaying nuclear division until cells have successfully constructed a bud. The cell cycle delay is due to the mitosis-inhibitory kinase Swe1p, which phosphorylates the cyclin-dependent kinase Cdc28p. In unperturbed cells, Swe1p is degraded via a mechanism thought to involve its tethering to a cortical scaffold of septin proteins at the mother-bud neck. In cells that experience stresses that delay bud formation, Swe1p is stabilized, accumulates, and promotes a G 2 delay. The tethering of Swe1p to the neck requires two regulators, called Hsl1p and Hsl7p. Hsl1p interacts with septins, and Hsl7p interacts with Swe1p; tethering occurs when Hsl1p interacts with Hsl7p. Here we created a version of Swe1p that is artificially tethered to the neck by fusion to a septin so that Swe1p no longer requires Hsl1p or Hsl7p for its localization to the neck. We show that the interaction between Hsl1p and Hsl7p, required for normal Swe1p degradation, is no longer needed for septin-Swe1p degradation, supporting the idea that the Hsl1p-Hsl7p interaction serves mainly to tether Swe1p to the neck. However, both Hsl1p and Hsl7p are still required for Swe1p degradation, implying that these proteins play additional roles beyond localizing Swe1p to the neck.

Histone H3 transcription in Saccharomyces cerevisiae is controlled by multiple cell cycle activation sites and a constitutive negative regulatory element

1992 ◽  
Vol 12 (12) ◽  
pp. 5455-5463 ◽  
Author(s):  
K B Freeman ◽  
L R Karns ◽  
K A Lutz ◽  
M M Smith
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Transcriptional Activation ◽  
Regulatory Element ◽  
Histone H3 ◽  
Regulatory Elements ◽  
Cell Division Cycle ◽  
Cell Cycle Activation ◽  
Multiple Cell

The promoters of the Saccharomyces cerevisiae histone H3 and H4 genes were examined for cis-acting DNA sequence elements regulating transcription and cell division cycle control. Deletion and linker disruption mutations identified two classes of regulatory elements: multiple cell cycle activation (CCA) sites and a negative regulatory site (NRS). Duplicate 19-bp CCA sites are present in both the copy I and copy II histone H3-H4 promoters arranged as inverted repeats separated by 45 and 68 bp. The CCA sites are both necessary and sufficient to activate transcription under cell division cycle control. A single CCA site provides cell cycle control but is a weak transcriptional activator, while an inverted repeat comprising two CCA sites provides both strong transcriptional activation and cell division cycle control. The NRS was identified in the copy I histone H3-H4 promoter. Deletion or disruption of the NRS increased the level of the histone H3 promoter activity but did not alter the cell division cycle periodicity of transcription. When the CCA sites were deleted from the histone promoter, the NRS element was unable to confer cell division cycle control on the remaining basal level of transcription. When the NRS element was inserted into the promoter of a foreign reporter gene, transcription was constitutively repressed and did not acquire cell cycle regulation.

scholarly journals p12DOC-1 Is a Novel Cyclin-Dependent Kinase 2-Associated Protein

2000 ◽  
Vol 20 (17) ◽  
pp. 6300-6307 ◽  
Author(s):  
Satoru Shintani ◽  
Hiroe Ohyama ◽  
Xue Zhang ◽  
Jim McBride ◽  
Kou Matsuo ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Ectopic Expression ◽  
Cell Division Cycle ◽  
Cyclin Dependent Kinase ◽  
Data Support ◽  
Normal Keratinocytes ◽  
Active Pool ◽  
Growth Suppressor

ABSTRACT Regulated cyclin-dependent kinase (CDK) levels and activities are critical for the proper progression of the cell division cycle. p12DOC-1 is a growth suppressor isolated from normal keratinocytes. We report that p12DOC-1 associates with CDK2. More specifically, p12DOC-1 associates with the monomeric nonphosphorylated form of CDK2 (p33CDK2). Ectopic expression of p12DOC-1 resulted in decreased cellular CDK2 and reduced CDK2-associated kinase activities and was accompanied by a shift in the cell cycle positions of p12DOC-1transfectants (↑ G1 and ↓ S). The p12DOC-1-mediated decrease of CDK2 was prevented if the p12DOC-1 transfectants were grown in the presence of the proteosome inhibitor clasto-lactacystin β-lactone, suggesting that p12DOC-1 may target CDK2 for proteolysis. A CDK2 binding mutant was created and was found to revert p12DOC-1-mediated, CDK2-associated cell cycle phenotypes. These data support p12DOC-1 as a specific CDK2-associated protein that negatively regulates CDK2 activities by sequestering the monomeric pool of CDK2 and/or targets CDK2 for proteolysis, reducing the active pool of CDK2.

scholarly journals Checkpoint genes required to delay cell division in response to nocodazole respond to impaired kinetochore function in the yeast Saccharomyces cerevisiae.

1995 ◽  
Vol 15 (12) ◽  
pp. 6838-6844 ◽  
Author(s):  
Y Wang ◽  
D J Burke
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cell Cycle Delay ◽  
Delay Cell ◽  
Antimitotic Drugs ◽  
Checkpoint Genes ◽  
Spindle Structure ◽  
Kinetochore Function

Inhibition of mitosis by antimitotic drugs is thought to occur by destruction of microtubules, causing cells to arrest through the action of one or more mitotic checkpoints. We have patterned experiments in the yeast Saccharomyces cerevisiae after recent studies in mammalian cells that demonstrate the effectiveness of antimitotic drugs at concentrations that maintain spindle structure. We show that low concentrations of nocodazole delay cell division under the control of the previously identified mitotic checkpoint genes BUB1, BUB3, MAD1, and MAD2 and independently of BUB2. The same genes mediate the cell cycle delay induced in ctf13 mutants, limited for an essential kinetochore component. Our data suggest that a low concentration of nocodazole induces a cell cycle delay through checkpoint control that is sensitive to impaired kinetochore function. The BUB2 gene may be part of a separate checkpoint that responds to abnormal spindle structure.

scholarly journals Suspended Animation Extends Survival Limits of Caenorhabditis elegans and Saccharomyces cerevisiae at Low Temperature

2010 ◽  
Vol 21 (13) ◽  
pp. 2161-2171 ◽  
Author(s):  
Kin Chan ◽  
Jesse P. Goldmark ◽  
Mark B. Roth
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Caenorhabditis Elegans ◽  
Cell Division Cycle ◽  
Wild Type ◽  
Suspended Animation ◽  
C Elegans ◽  
High Viability ◽  
Cold Sensitive

The orderly progression through the cell division cycle is of paramount importance to all organisms, as improper progression through the cycle could result in defects with grave consequences. Previously, our lab has shown that model eukaryotes such as Saccharomyces cerevisiae, Caenorhabditis elegans, and Danio rerio all retain high viability after prolonged arrest in a state of anoxia-induced suspended animation, implying that in such a state, progression through the cell division cycle is reversibly arrested in an orderly manner. Here, we show that S. cerevisiae (both wild-type and several cold-sensitive strains) and C. elegans embryos exhibit a dramatic decrease in viability that is associated with dysregulation of the cell cycle when exposed to low temperatures. Further, we find that when the yeast or worms are first transitioned into a state of anoxia-induced suspended animation before cold exposure, the associated cold-induced viability defects are largely abrogated. We present evidence that by imposing an anoxia-induced reversible arrest of the cell cycle, the cells are prevented from engaging in aberrant cell cycle events in the cold, thus allowing the organisms to avoid the lethality that would have occurred in a cold, oxygenated environment.

scholarly journals Mammalian Orc1 Protein Is Selectively Released from Chromatin and Ubiquitinated during the S-to-M Transition in the Cell Division Cycle

2002 ◽  
Vol 22 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Cong-Jun Li ◽  
Melvin L. DePamphilis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Schizosaccharomyces Pombe ◽  
Half Life ◽  
S Phase ◽  
Cell Division Cycle ◽  
26S Proteasome ◽  
Selective Dissociation

ABSTRACT Previous studies have shown that changes in the affinity of the hamster Orc1 protein for chromatin during the M-to-G1 transition correlate with the activity of hamster origin recognition complexes (ORCs) and the appearance of prereplication complexes at specific sites. Here we show that Orc1 is selectively released from chromatin as cells enter S phase, converted into a mono- or diubiquitinated form, and then deubiquitinated and re-bound to chromatin during the M-to-G1 transition. Orc1 is degraded by the 26S proteasome only when released into the cytosol, and peptide additions to Orc1 make it hypersensitive to polyubiquitination. In contrast, Orc2 remains tightly bound to chromatin throughout the cell cycle and is not a substrate for ubiquitination. Since the concentration of Orc1 remains constant throughout the cell cycle, and its half-life in vivo is the same as that of Orc2, ubiquitination of non-chromatin-bound Orc1 presumably facilitates the inactivation of ORCs by sequestering Orc1 during S phase. Thus, in contrast to yeast (Saccharomyces cerevisiae and Schizosaccharomyces pombe), mammalian ORC activity appears to be regulated during each cell cycle through selective dissociation and reassociation of Orc1 from chromatin-bound ORCs.

scholarly journals Gene Expression Changes and Anti-proliferative Effect of Noni (Morinda Citrifolia) Fruit Extract Analysed by Real Time-PCR

Molekul ◽  
2017 ◽  
Vol 12 (1) ◽  
pp. 37
Author(s):  
Hermansyah Hermansyah ◽  
Susilawati Susilawati
Keyword(s):  
Gene Expression ◽  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Real Time ◽  
Cell Division Cycle ◽  
Morinda Citrifolia ◽  
Transcriptional Analysis ◽  
Fruit Extract ◽  
Proliferative Effect

To elucidate the anti-proliferative effect of noni (Morinda citrifolia) fruit extract for a Saccharomyces cerevisiae model organism, analysis of gene expression changes related to cell cycle associated with inhibition effect of noni fruit extract was carried out. Anti-proliferative of noni fruit extract was analyzed using gene expression changes of Saccharomyces cerevisiae (strains FY833 and BY4741).  Transcriptional analysis of genes that play a role in cell cycle was conducted by growing cells on YPDAde broth medium containing 1% (w/v) noni fruit extract, and then subjected using quantitative real-time polymerase chain reaction (RT-PCR).  Transcriptional level of genes CDC6 (Cell Division Cycle-6), CDC20 (Cell Division Cycle-20), FAR1 (Factor ARrest-1), FUS3 (FUSsion-3), SIC1 (Substrate/Subunit Inhibitor of Cyclin-dependent protein kinase-1), WHI5 (WHIskey-5), YOX1 (Yeast homeobOX-1) and YHP1 (Yeast Homeo-Protein-1) increased, oppositely genes expression of DBF4 (DumbBell Forming), MCM1 (Mini Chromosome Maintenance-1) and TAH11 (Topo-A Hypersensitive-11) decreased, while the expression level of genes CDC7 (Cell Division Cycle-7), MBP1 (MIul-box Binding Protein-1) and SWI6 (SWItching deficient-6) relatively unchanged. These results indicated that gene expression changes might associate with anti-proliferative effect from noni fruit extract. These gene expressions changes lead to the growth inhibition of S.cerevisiae cell because of cell cycle defect.

scholarly journals Histone H3 transcription in Saccharomyces cerevisiae is controlled by multiple cell cycle activation sites and a constitutive negative regulatory element.

1992 ◽  
Vol 12 (12) ◽  
pp. 5455-5463 ◽  
Author(s):  
K B Freeman ◽  
L R Karns ◽  
K A Lutz ◽  
M M Smith
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Transcriptional Activation ◽  
Regulatory Element ◽  
Histone H3 ◽  
Regulatory Elements ◽  
Cell Division Cycle ◽  
Cell Cycle Activation ◽  
Multiple Cell

The promoters of the Saccharomyces cerevisiae histone H3 and H4 genes were examined for cis-acting DNA sequence elements regulating transcription and cell division cycle control. Deletion and linker disruption mutations identified two classes of regulatory elements: multiple cell cycle activation (CCA) sites and a negative regulatory site (NRS). Duplicate 19-bp CCA sites are present in both the copy I and copy II histone H3-H4 promoters arranged as inverted repeats separated by 45 and 68 bp. The CCA sites are both necessary and sufficient to activate transcription under cell division cycle control. A single CCA site provides cell cycle control but is a weak transcriptional activator, while an inverted repeat comprising two CCA sites provides both strong transcriptional activation and cell division cycle control. The NRS was identified in the copy I histone H3-H4 promoter. Deletion or disruption of the NRS increased the level of the histone H3 promoter activity but did not alter the cell division cycle periodicity of transcription. When the CCA sites were deleted from the histone promoter, the NRS element was unable to confer cell division cycle control on the remaining basal level of transcription. When the NRS element was inserted into the promoter of a foreign reporter gene, transcription was constitutively repressed and did not acquire cell cycle regulation.

scholarly journals Sensing a bud in the yeast morphogenesis checkpoint: a role for Elm1

2016 ◽  
Vol 27 (11) ◽  
pp. 1764-1775 ◽  
Author(s):  
Hui Kang ◽  
Denis Tsygankov ◽  
Daniel J. Lew
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Division ◽  
Environmental Stresses ◽  
Bud Formation ◽  
Septin Ring ◽  
Bud Emergence ◽  
Bud Neck ◽  
Morphogenesis Checkpoint ◽  
Bud Site ◽  
Mitotic Inhibitor

Bud formation by Saccharomyces cerevisiae must be coordinated with the nuclear cycle to enable successful proliferation. Many environmental stresses temporarily disrupt bud formation, and in such circumstances, the morphogenesis checkpoint halts nuclear division until bud formation can resume. Bud emergence is essential for degradation of the mitotic inhibitor, Swe1. Swe1 is localized to the septin cytoskeleton at the bud neck by the Swe1-binding protein Hsl7. Neck localization of Swe1 is required for Swe1 degradation. Although septins form a ring at the presumptive bud site before bud emergence, Hsl7 is not recruited to the septins until after bud emergence, suggesting that septins and/or Hsl7 respond to a “bud sensor.” Here we show that recruitment of Hsl7 to the septin ring depends on a combination of two septin-binding kinases: Hsl1 and Elm1. We elucidate which domains of these kinases are needed and show that artificial targeting of those domains suffices to recruit Hsl7 to septin rings even in unbudded cells. Moreover, recruitment of Elm1 is responsive to bud emergence. Our findings suggest that Elm1 plays a key role in sensing bud emergence.

scholarly journals Telomere Cap Components Influence the Rate of Senescence in Telomerase-Deficient Yeast Cells

2004 ◽  
Vol 24 (2) ◽  
pp. 837-845 ◽  
Author(s):  
Shinichiro Enomoto ◽  
Lynn Glowczewski ◽  
Jodi Lew-Smith ◽  
Judith G. Berman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Yeast Cells ◽  
Progressive Reduction ◽  
Delayed Senescence ◽  
Cell Cycle Delay ◽  
Nonsense Mediated Mrna Decay ◽  
A Cell ◽  
Population Doublings

ABSTRACT Cells lacking telomerase undergo senescence, a progressive reduction in cell division that involves a cell cycle delay and culminates in “crisis,” a period when most cells become inviable. In telomerase-deficient Saccharomyces cerevisiae cells lacking components of the nonsense-mediated mRNA decay (NMD) pathway (Upf1,Upf2, or Upf3 proteins), senescence is delayed, with crisis occurring ∼10 to 25 population doublings later than in Upf+ cells. Delayed senescence is seen in upfΔ cells lacking the telomerase holoenzyme components Est2p and TLC1 RNA, as well as in cells lacking the telomerase regulators Est1p and Est3p. The delay of senescence in upfΔ cells is not due to an increased rate of survivor formation. Rather, it is caused by alterations in the telomere cap, composed of Cdc13p, Stn1p, and Ten1p. In upfΔ mutants, STN1 and TEN1 levels are increased. Increasing the levels of Stn1p and Ten1p in Upf+ cells is sufficient to delay senescence. In addition, cdc13-2 mutants exhibit delayed senescence rates similar to those of upfΔ cells. Thus, changes in the telomere cap structure are sufficient to affect the rate of senescence in the absence of telomerase. Furthermore, the NMD pathway affects the rate of senescence in telomerase-deficient cells by altering the stoichiometry of telomere cap components.

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