scholarly journals Multiple classes of yeast mutants are defective in vacuole partitioning yet target vacuole proteins correctly.

1996 ◽  
Vol 7 (9) ◽  
pp. 1375-1389 ◽  
Author(s):  
Y X Wang ◽  
H Zhao ◽  
T M Harding ◽  
D S Gomes de Mesquita ◽  
C L Woldringh ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Basis ◽  
Protein Delivery ◽  
Protein Transport ◽  
Daughter Cells ◽  
A Cell ◽  
Complementation Groups ◽  
Vacuole Inheritance ◽  
Mother Cells ◽  
Yeast Mutants

In Saccharomyces cerevisiae the vacuoles are partitioned from mother cells to daughter cells in a cell-cycle-coordinated process. The molecular basis of this event remains obscure. To date, few yeast mutants had been identified that are defective in vacuole partitioning (vac), and most such mutants are also defective in vacuole protein sorting (vps) from the Golgi to the vacuole. Both the vps mutants and previously identified non-vps vac mutants display an altered vacuolar morphology. Here, we report a new method to monitor vacuole inheritance and the isolation of six new non-vps vac mutants. They define five complementation groups (VAC8-VAC12). Unlike mutants identified previously, three of the complementation groups exhibit normal vacuolar morphology. Zygote studies revealed that these vac mutants are also defective in intervacuole communication. Although at least four pathways of protein delivery to the vacuole are known, only the Vps pathway seems to significantly overlap with vacuole partitioning. Mutants defective in both vacuole partitioning and endocytosis or vacuole partitioning and autophagy were not observed. However, one of the new vac mutants was additionally defective in direct protein transport from the cytoplasm to the vacuole.

Chitin scar breaks in aged Saccharomyces cerevisiae

Microbiology ◽  
2003 ◽  
Vol 149 (11) ◽  
pp. 3129-3137 ◽  
Author(s):  
Chris D. Powell ◽  
David E. Quain ◽  
Katherine A. Smart
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Surface ◽  
Daughter Cell ◽  
Scar Tissue ◽  
Daughter Cells ◽  
Cell Age ◽  
Mother And Daughter ◽  
A Cell ◽  
Cell Surface Changes ◽  
Mother Cells

Ageing in budding yeast is not determined by chronological lifespan, but by the number of times an individual cell is capable of dividing, termed its replicative capacity. As cells age they are subject to characteristic cell surface changes. Saccharomyces cerevisiae reproduces asexually by budding and as a consequence of this process both mother and daughter cell retain chitinous scar tissue at the point of cytokinesis. Daughter cells exhibit a frail structure known as the birth scar, while mother cells display a more persistent bud scar. The number of bud scars present on the cell surface is directly related to the number of times a cell has divided and thus constitutes a biomarker for replicative cell age. It has been proposed that the birth scar may be subject to stretching caused by expansion of the daughter cell; however, no previous analysis of the effect of cell age on birth or bud scar size has been reported. This paper provides evidence that scar tissue expands with the cell during growth. It is postulated that symmetrically arranged breaks in the bud scar allow these rigid chitinous structures to expand without compromising cellular integrity.

scholarly journals Daughter cells of Saccharomyces cerevisiae from old mothers display a reduced life span.

1994 ◽  
Vol 127 (6) ◽  
pp. 1985-1993 ◽  
Author(s):  
B K Kennedy ◽  
N R Austriaco ◽  
L Guarente
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Life Span ◽  
Daughter Cell ◽  
Young Mothers ◽  
Young Mother ◽  
Yeast Saccharomyces Cerevisiae ◽  
Daughter Cells ◽  
Per Se ◽  
Mother Cells ◽  
Maximum Occurrence

The yeast Saccharomyces cerevisiae typically divides asymmetrically to give a large mother cell and a smaller daughter cell. As mother cells become old, they enlarge and produce daughter cells that are larger than daughters derived from young mother cells. We found that occasional daughter cells were indistinguishable in size from their mothers, giving rise to a symmetric division. The frequency of symmetric divisions became greater as mother cells aged and reached a maximum occurrence of 30% in mothers undergoing their last cell division. Symmetric divisions occurred similarly in rad9 and ste12 mutants. Strikingly, daughters from old mothers, whether they arose from symmetric divisions or not, displayed reduced life spans relative to daughters from young mothers. Because daughters from old mothers were larger than daughters from young mothers, we investigated whether an increased size per se shortened life span and found that it did not. These findings are consistent with a model for aging that invokes a senescence substance which accumulates in old mother cells and is inherited by their daughters.

scholarly journals FACT and Ash1 promote long-range and bidirectional nucleosome eviction at the HO promoter

2020 ◽  
Vol 48 (19) ◽  
pp. 10877-10889 ◽  
Author(s):  
Yaxin Yu ◽  
Robert M Yarrington ◽  
David J Stillman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Regulatory System ◽  
High Concentration ◽  
Long Distance ◽  
Mothers And Daughters ◽  
Daughter Cells ◽  
Dna Binding Factors ◽  
Mother Cells ◽  
Promoter Recruitment ◽  
Ho Gene

Abstract The Saccharomyces cerevisiae HO gene is a model regulatory system with complex transcriptional regulation. Budding yeast divide asymmetrically and HO is expressed only in mother cells where a nucleosome eviction cascade along the promoter during the cell cycle enables activation. HO expression in daughter cells is inhibited by high concentration of Ash1 in daughters. To understand how Ash1 represses transcription, we used a myo4 mutation which boosts Ash1 accumulation in both mothers and daughters and show that Ash1 inhibits promoter recruitment of SWI/SNF and Gcn5. We show Ash1 is also required for the efficient nucleosome repopulation that occurs after eviction, and the strongest effects of Ash1 are seen when Ash1 has been degraded and at promoter locations distant from where Ash1 bound. Additionally, we defined a specific nucleosome/nucleosome-depleted region structure that restricts HO activation to one of two paralogous DNA-binding factors. We also show that nucleosome eviction occurs bidirectionally over a large distance. Significantly, eviction of the more distant nucleosomes is dependent upon the FACT histone chaperone, and FACT is recruited to these regions when eviction is beginning. These last observations, along with ChIP experiments involving the SBF factor, suggest a long-distance loop transiently forms at the HO promoter.

scholarly journals Cell cycle phases in the unequal mother/daughter cell cycles of Saccharomyces cerevisiae.

1984 ◽  
Vol 4 (11) ◽  
pp. 2529-2531 ◽  
Author(s):  
B J Brewer ◽  
E Chlebowicz-Sledziewska ◽  
W L Fangman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cycle Phase ◽  
Cell Cycle Time ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cell Cycles ◽  
Daughter Cells ◽  
Mother And Daughter ◽  
Cell Cycle Phases ◽  
Mother Cells

During cell division in the yeast Saccharomyces cerevisiae mother cells produce buds (daughter cells) which are smaller and have longer cell cycles. We performed experiments to compare the lengths of cell cycle phases in mothers and daughters. As anticipated from earlier indirect observations, the longer cell cycle time of daughter cells is accounted for by a longer G1 interval. The S-phase and the G2-phase are of the same duration in mother and daughter cells. An analysis of five isogenic strains shows that cell cycle phase lengths are independent of cell ploidy and mating type.

scholarly journals The newly identified yeast GRD genes are required for retention of late-Golgi membrane proteins.

1996 ◽  
Vol 16 (6) ◽  
pp. 2700-2707 ◽  
Author(s):  
S F Nothwehr ◽  
N J Bryant ◽  
T H Stevens
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alkaline Phosphatase ◽  
Membrane Proteins ◽  
Golgi Membrane ◽  
Golgi Retention ◽  
Complementation Groups ◽  
Aminopeptidase A ◽  
Dipeptidyl Aminopeptidase ◽  
Yeast Mutants ◽  
Kinetics Of

Processing of A-ALP, a late-Golgi membrane protein constructed by fusing the cytosolic domain of dipeptidyl aminopeptidase A to the transmembrane and lumenal domains of alkaline phosphatase (ALP), serves as a convenient assay for loss of retention of late-Golgi membrane proteins in Saccharomyces cerevisiae. In this study, a large group of novel grd (for Golgi retention defective) yeast mutants, representing 18 complementation groups, were identified on the basis of their mislocalization of A-ALP to the vacuole, where it was proteolytically processed and thus became enzymatically activated. All of the grd mutants exhibited significant mislocalization of A-ALP, as measured by determining the kinetics of A-ALP processing and by analyzing its

scholarly journals Vacuole Biogenesis in Saccharomyces cerevisiae: Protein Transport Pathways to the Yeast Vacuole

1998 ◽  
Vol 62 (1) ◽  
pp. 230-247 ◽  
Author(s):  
Nia J. Bryant ◽  
Tom H. Stevens
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Delivery ◽  
Secretory Pathway ◽  
Protein Transport ◽  
Transport Pathway ◽  
Yeast Saccharomyces Cerevisiae ◽  
Transport Pathways ◽  
Yeast Vacuole ◽  
Lysosome Biogenesis ◽  
Vacuolar Protein

SUMMARY Delivery of proteins to the vacuole of the yeast Saccharomyces cerevisiae provides an excellent model system in which to study vacuole and lysosome biogenesis and membrane traffic. This organelle receives proteins from a number of different routes, including proteins sorted away from the secretory pathway at the Golgi apparatus and endocytic traffic arising from the plasma membrane. Genetic analysis has revealed at least 60 genes involved in vacuolar protein sorting, numerous components of a novel cytoplasm-to-vacuole transport pathway, and a large number of proteins required for autophagy. Cell biological and biochemical studies have provided important molecular insights into the various protein delivery pathways to the yeast vacuole. This review describes the various pathways to the vacuole and illustrates how they are related to one another in the vacuolar network of S. cerevisiae.

scholarly journals Mutants in three novel complementation groups inhibit membrane protein insertion into and soluble protein translocation across the endoplasmic reticulum membrane of Saccharomyces cerevisiae.

1992 ◽  
Vol 116 (3) ◽  
pp. 597-604 ◽  
Author(s):  
N Green ◽  
H Fang ◽  
P Walter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Protein ◽  
Protein Transport ◽  
Protein Translocation ◽  
Soluble Proteins ◽  
Endoplasmic Reticulum Membrane ◽  
Protein Insertion ◽  
Membrane Protein Insertion ◽  
Complementation Groups ◽  
Er Membrane

We have isolated mutants that inhibit membrane protein insertion into the ER membrane of Saccharomyces cerevisiae. The mutants were contained in three complementation groups, which we have named SEC70, SEC71, and SEC72. The mutants also inhibited the translocation of soluble proteins into the lumen of the ER, indicating that they pleiotropically affect protein transport across and insertion into the ER membrane. Surprisingly, the mutants inhibited the translocation and insertion of different proteins to drastically different degrees. We have also shown that mutations in SEC61 and SEC63, which were previously isolated as mutants inhibiting the translocation of soluble proteins, also affect the insertion of membrane proteins into the ER. Taken together our data indicate that the process of protein translocation across the ER membrane involves a much larger number of gene products than previously appreciated. Moreover, different translocation substrates appear to have different requirements for components of the cellular targeting and translocation apparatus.

scholarly journals O-Glycosylation of Axl2/Bud10p by Pmt4p Is Required for Its Stability, Localization, and Function in Daughter Cells

1999 ◽  
Vol 145 (6) ◽  
pp. 1177-1188 ◽  
Author(s):  
Sylvia L. Sanders ◽  
Martina Gentzsch ◽  
Widmar Tanner ◽  
Ira Herskowitz
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Site Selection ◽  
Surface Proteins ◽  
Cell Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cell Surface Proteins ◽  
Daughter Cells ◽  
Mother Cells ◽  
And Function ◽  
Bud Site

Cells of the yeast Saccharomyces cerevisiae choose bud sites in a manner that is dependent upon cell type: a and α cells select axial sites; a/α cells utilize bipolar sites. Mutants specifically defective in axial budding were isolated from an α strain using pseudohyphal growth as an assay. We found that a and α mutants defective in the previously identified PMT4 gene exhibit unipolar, rather than axial budding: mother cells choose axial bud sites, but daughter cells do not. PMT4 encodes a protein mannosyl transferase (pmt) required for O-linked glycosylation of some secretory and cell surface proteins (Immervoll, T., M. Gentzsch, and W. Tanner. 1995. Yeast. 11:1345–1351). We demonstrate that Axl2/Bud10p, which is required for the axial budding pattern, is an O-linked glycoprotein and is incompletely glycosylated, unstable, and mislocalized in cells lacking PMT4. Overexpression of AXL2 can partially restore proper bud-site selection to pmt4 mutants. These data indicate that Axl2/Bud10p is glycosylated by Pmt4p and that O-linked glycosylation increases Axl2/ Bud10p activity in daughter cells, apparently by enhancing its stability and promoting its localization to the plasma membrane.

scholarly journals Yeast Mutants Deficient in ER-Associated Degradation of the Z Variant of Alpha-1-Protease Inhibitor

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1355-1362 ◽  
Author(s):  
Ardythe A McCracken ◽  
Igor V Karpichev ◽  
James E Ernaga ◽  
Eric D Werner ◽  
Andrew G Dillin ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Degradation ◽  
Proteinase Inhibitor ◽  
Parent Strain ◽  
Mendelian Inheritance ◽  
Wild Type ◽  
Mutant Strains ◽  
Complementation Groups ◽  
Yeast Mutants ◽  
Wild Type Yeast

Saccharomyces cerevisiae mutants deficient in degradation of alpha-1-proteinase inhibitor Z (A1PiZ) have been isolated and genetically characterized. Wild-type yeast expressing A1PiZ synthesize an ER form of this protein that is rapidly degraded by an intracellular proteolytic process known as ER-associated protein degradation (ERAD). The mutant strains were identified after treatment with EMS using a colony blot immunoassay to detect colonies that accumulated high levels of A1PiZ. A total of 120,000 colonies were screened and 30 putative mutants were identified. The level of A1PiZ accumulation in these mutants, measured by ELISA, ranged from two to 11 times that of A1PiZ in the parent strain. Further studies demonstrated that the increased levels of A1PiZ in most of the mutant strains was not the result of defective secretion or elevated A1PiZ mRNA. Pulse chase experiments indicated that A1PiZ was stabilized in several strains, evidence that these mutants are defective in ER-associated protein degradation. Genetic analyses revealed that most of the mutations were recessive, ∼30% of the mutants characterized conformed to simple Mendelian inheritance, and at least seven complementation groups were identified.

scholarly journals Patterns of bud-site selection in the yeast Saccharomyces cerevisiae.

1995 ◽  
Vol 129 (3) ◽  
pp. 751-765 ◽  
Author(s):  
J Chant ◽  
J R Pringle
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Time Lapse ◽  
Growth Conditions ◽  
Alpha Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cell Cycles ◽  
Daughter Cells ◽  
Division Site ◽  
Mother Cells ◽  
Bud Site

Cells of the yeast Saccharomyces cerevisiae select bud sites in either of two distinct spatial patterns, known as axial (expressed by a and alpha cells) and bipolar (expressed by a/alpha cells). Fluorescence, time-lapse, and scanning electron microscopy have been used to obtain more precise descriptions of these patterns. From these descriptions, we conclude that in the axial pattern, the new bud forms directly adjacent to the division site in daughter cells and directly adjacent to the immediately preceding division site (bud site) in mother cells, with little influence from earlier sites. Thus, the division site appears to be marked by a spatial signal(s) that specifies the location of the new bud site and is transient in that it only lasts from one budding event to the next. Consistent with this conclusion, starvation and refeeding of axially budding cells results in the formation of new buds at nonaxial sites. In contrast, in bipolar budding cells, both poles are specified persistently as potential bud sites, as shown by the observations that a pole remains competent for budding even after several generations of nonuse and that the poles continue to be used for budding after starvation and refeeding. It appears that the specification of the two poles as potential bud sites occurs before a daughter cell forms its first bud, as a daughter can form this bud near either pole. However, there is a bias towards use of the pole distal to the division site. The strength of this bias varies from strain to strain, is affected by growth conditions, and diminishes in successive cell cycles. The first bud that forms near the distal pole appears to form at the very tip of the cell, whereas the first bud that forms near the pole proximal to the original division site (as marked by the birth scar) is generally somewhat offset from the tip and adjacent to (or overlapping) the birth scar. Subsequent buds can form near either pole and appear almost always to be adjacent either to the birth scar or to a previous bud site. These observations suggest that the distal tip of the cell and each division site carry persistent signals that can direct the selection of a bud site in any subsequent cell cycle.

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