scholarly journals Molecular mechanisms of microtubule-dependent kinetochore transport toward spindle poles

2007 ◽  
Vol 178 (2) ◽  
pp. 269-281 ◽  
Author(s):  
Kozo Tanaka ◽  
Etsushi Kitamura ◽  
Yoko Kitamura ◽  
Tomoyuki U. Tanaka
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Family Member ◽  
Lateral Surface ◽  
Molecular Mechanisms ◽  
Microtubule Depolymerization ◽  
Spindle Poles ◽  
Dam1 Complex ◽  
Pulling Force

In mitosis, kinetochores are initially captured by the lateral sides of single microtubules and are subsequently transported toward spindle poles. Mechanisms for kinetochore transport are not yet known. We present two mechanisms involved in microtubule-dependent poleward kinetochore transport in Saccharomyces cerevisiae. First, kinetochores slide along the microtubule lateral surface, which is mainly and probably exclusively driven by Kar3, a kinesin-14 family member that localizes at kinetochores. Second, kinetochores are tethered at the microtubule distal ends and pulled poleward as microtubules shrink (end-on pulling). Kinetochore sliding is often converted to end-on pulling, enabling more processive transport, but the opposite conversion is rare. The establishment of end-on pulling is partly hindered by Kar3, and its progression requires the Dam1 complex. We suggest that the Dam1 complexes, which probably encircle a single microtubule, can convert microtubule depolymerization into the poleward kinetochore-pulling force. Thus, microtubule-dependent poleward kinetochore transport is ensured by at least two distinct mechanisms.

scholarly journals Efficient Chromosome Biorientation and the Tension Checkpoint in Saccharomyces cerevisiae both Require Bir1

2009 ◽  
Vol 29 (16) ◽  
pp. 4552-4562 ◽  
Author(s):  
Vasso Makrantoni ◽  
Michael J. R. Stark
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Chromosome Segregation ◽  
Temperature Sensitive ◽  
Protein Kinase Activity ◽  
Restrictive Temperature ◽  
Microtubule Depolymerization ◽  
Spindle Poles ◽  
Sister Kinetochore

ABSTRACT Accurate chromosome segregation requires the capture of sister kinetochores by microtubules from opposite spindle poles prior to the initiation of anaphase, a state termed chromosome biorientation. In the budding yeast Saccharomyces cerevisiae, the conserved protein kinase Ipl1 (Aurora B in metazoans) is critical for ensuring correct chromosomal alignment. Ipl1 associates with its activators Sli15 (INCENP), Nbl1 (Borealin), and Bir1 (Survivin), but while Sli15 clearly functions with Ipl1 to promote chromosome biorientation, the role of Bir1 has been uncertain. Using a temperature-sensitive bir1 mutant (bir1-17), we show that Bir1 is needed to permit efficient chromosome biorientation. However, once established, chromosome biorientation is maintained in bir1-17 cells at the restrictive temperature. Ipl1 is partially delocalized in bir1-17 cells, and its protein kinase activity is markedly reduced under nonpermissive conditions. bir1-17 cells arrest normally in response to microtubule depolymerization but fail to delay anaphase when sister kinetochore tension is reduced. Thus, Bir1 is required for the tension checkpoint. Despite their robust mitotic arrest in response to nocodazole, bir1-17 cells are hypersensitive to microtubule-depolymerizing drugs and show a more severe biorientation defect on recovery from nocodazole treatment. The role of Bir1 therefore may become more critical when spindle formation is delayed.

scholarly journals Molecular Mechanisms of ZC3H12C/Reg-3 Biological Activity and Its Involvement in Psoriasis Pathology

2021 ◽  
Vol 22 (14) ◽  
pp. 7311
Author(s):  
Mateusz Wawro ◽  
Jakub Kochan ◽  
Weronika Sowinska ◽  
Aleksandra Solecka ◽  
Karolina Wawro ◽  
...  
Keyword(s):  
Family Member ◽  
Cellular Localization ◽  
Molecular Mechanisms ◽  
Inflammatory Diseases ◽  
Association Studies ◽  
Psoriasis Patient ◽  
Genome Wide Association Studies ◽  
Mrna Levels ◽  
Transcript Levels

The members of the ZC3H12/MCPIP/Regnase family of RNases have emerged as important regulators of inflammation. In contrast to Regnase-1, -2 and -4, a thorough characterization of Regnase-3 (Reg-3) has not yet been explored. Here we demonstrate that Reg-3 differs from other family members in terms of NYN/PIN domain features, cellular localization pattern and substrate specificity. Together with Reg-1, the most comprehensively characterized family member, Reg-3 shared IL-6, IER-3 and Reg-1 mRNAs, but not IL-1β mRNA, as substrates. In addition, Reg-3 was found to be the only family member which regulates transcript levels of TNF, a cytokine implicated in chronic inflammatory diseases including psoriasis. Previous meta-analysis of genome-wide association studies revealed Reg-3 to be among new psoriasis susceptibility loci. Here we demonstrate that Reg-3 transcript levels are increased in psoriasis patient skin tissue and in an experimental model of psoriasis, supporting the immunomodulatory role of Reg-3 in psoriasis, possibly through degradation of mRNA for TNF and other factors such as Reg-1. On the other hand, Reg-1 was found to destabilize Reg-3 transcripts, suggesting reciprocal regulation between Reg-3 and Reg-1 in the skin. We found that either Reg-1 or Reg-3 were expressed in human keratinocytes in vitro. However, in contrast to robustly upregulated Reg-1 mRNA levels, Reg-3 expression was not affected in the epidermis of psoriasis patients. Taken together, these data suggest that epidermal levels of Reg-3 are negatively regulated by Reg-1 in psoriasis, and that Reg-1 and Reg-3 are both involved in psoriasis pathophysiology through controlling, at least in part different transcripts.

scholarly journals Feeding a Saccharomyces cerevisiae fermentation product improves udder health and immune response to a Streptococcus uberis mastitis challenge in mid-lactation dairy cows

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
M. Vailati-Riboni ◽  
D. N. Coleman ◽  
V. Lopreiato ◽  
A. Alharthi ◽  
R. E. Bucktrout ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Somatic Cell ◽  
Pathway Analysis ◽  
Molecular Mechanisms ◽  
Somatic Cell Score ◽  
Molecular Networks ◽  
Epithelial Tissue ◽  
Udder Health ◽  
Streptococcus Uberis ◽  
Fermentation Product

Abstract Background We aimed to characterize the protective effects and the molecular mechanisms of action of a Saccharomyces cerevisiae fermentation product (NTK) in response to a mastitis challenge. Eighteen mid-lactation multiparous Holstein cows (n = 9/group) were fed the control diet (CON) or CON supplemented with 19 g/d NTK for 45 d (phase 1, P1) and then infected in the right rear quarter with 2500 CFU of Streptococcus uberis (phase 2, P2). After 36-h, mammary gland and liver biopsies were collected and antibiotic treatment started until the end of P2 (9 d post challenge). Cows were then followed until day 75 (phase 3, P3). Milk yield (MY) and dry matter intake (DMI) were recorded daily. Milk samples for somatic cell score were collected, and rectal and udder temperature, heart and respiration rate were recorded during the challenge period (P2) together with blood samples for metabolite and immune function analyses. Data were analyzed by phase using the PROC MIXED procedure in SAS. Biopsies were used for transcriptomic analysis via RNA-sequencing, followed by pathway analysis. Results DMI and MY were not affected by diet in P1, but an interaction with time was recorded in P2 indicating a better recovery from the challenge in NTK compared with CON. NTK reduced rectal temperature, somatic cell score, and temperature of the infected quarter during the challenge. Transcriptome data supported these findings, as NTK supplementation upregulated mammary genes related to immune cell antibacterial function (e.g., CATHL4, NOS2), epithelial tissue protection (e.g. IL17C), and anti-inflammatory activity (e.g., ATF3, BAG3, IER3, G-CSF, GRO1, ZFAND2A). Pathway analysis indicated upregulation of tumor necrosis factor α, heat shock protein response, and p21 related pathways in the response to mastitis in NTK cows. Other pathways for detoxification and cytoprotection functions along with the tight junction pathway were also upregulated in NTK-fed cows. Conclusions Overall, results highlighted molecular networks involved in the protective effect of NTK prophylactic supplementation on udder health during a subclinical mastitic event.

Analysis of Saccharomyces cerevisiae his3 transcription in vitro: biochemical support for multiple mechanisms of transcription

1990 ◽  
Vol 10 (6) ◽  
pp. 2832-2839
Author(s):  
A S Ponticelli ◽  
K Struhl
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcriptional Activation ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Initiation Site ◽  
Activator Proteins ◽  
Nuclear Extracts ◽  
Transcription In Vitro

The promoter region of the Saccharomyces cerevisiae his3 gene contains two TATA elements, TC and TR, that direct transcription initiation to two sites designated +1 and +13. On the basis of differences between their nucleotide sequences and their responsiveness to upstream promoter elements, it has previously been proposed that TC and TR promote transcription by different molecular mechanisms. To begin a study of his3 transcription in vitro, we used S. cerevisiae nuclear extracts together with various DNA templates and transcriptional activator proteins that have been characterized in vivo. We demonstrated accurate transcription initiation in vitro at the sites used in vivo, transcriptional activation by GCN4, and activation by a GAL4 derivative on various gal-his3 hybrid promoters. In all cases, transcription stimulation was dependent on the presence of an acidic activation region in the activator protein. In addition, analysis of promoters containing a variety of TR derivatives indicated that the level of transcription in vitro was directly related to the level achieved in vivo. The results demonstrated that the in vitro system accurately reproduced all known aspects of in vivo his3 transcription that depend on the TR element. However, in striking contrast to his3 transcription in vivo, transcription in vitro yielded approximately 20 times more of the +13 transcript than the +1 transcript. This result was not due to inability of the +1 initiation site to be efficiently utilized in vitro, but rather it reflects the lack of TC function in vitro. The results support the idea that TC and TR mediate transcription from the wild-type promoter by distinct mechanisms.

scholarly journals Saccharomyces cerevisiae— a model to uncover molecular mechanisms for yeast biofilm biology

2012 ◽  
Vol 65 (2) ◽  
pp. 169-182 ◽  
Author(s):  
Rasmus K. Bojsen ◽  
Kaj Scherz Andersen ◽  
Birgitte Regenberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Mechanisms

scholarly journals Capped mRNA Degradation Intermediates Accumulate in the Yeast spb8-2 Mutant

1998 ◽  
Vol 18 (9) ◽  
pp. 5062-5072 ◽  
Author(s):  
Ronald Boeck ◽  
Bruno Lapeyre ◽  
Christine E. Brown ◽  
Alan B. Sachs
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Family Member ◽  
Gene Deletion ◽  
Binding Protein ◽  
Mrna Degradation ◽  
Protein Family ◽  
Suppressor Mutation ◽  
Mrna Decapping ◽  
Mrna Species ◽  
Degradation Intermediates

ABSTRACT mRNA in the yeast Saccharomyces cerevisiae is primarily degraded through a pathway that is stimulated by removal of the mRNA cap structure. Here we report that a mutation in the SPB8(YJL124c) gene, initially identified as a suppressor mutation of a poly(A)-binding protein (PAB1) gene deletion, stabilizes the mRNA cap structure. Specifically, we find that thespb8-2 mutation results in the accumulation of capped, poly(A)-deficient mRNAs. The presence of this mutation also allows for the detection of mRNA species trimmed from the 3′ end. These data show that this Sm-like protein family member is involved in the process of mRNA decapping, and they provide an example of 3′-5′ mRNA degradation intermediates in yeast.

scholarly journals The AMPK Family Member Snf1 Protects Saccharomyces cerevisiae Cells upon Glutathione Oxidation

PLoS ONE ◽  
2013 ◽  
Vol 8 (3) ◽  
pp. e58283 ◽  
Author(s):  
Maria Pérez-Sampietro ◽  
Celia Casas ◽  
Enrique Herrero
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Family Member ◽  
Glutathione Oxidation

scholarly journals RNA sequencing reveals metabolic and regulatory changes leading to more robust fermentation performance during short-term adaptation of Saccharomyces cerevisiae to lignocellulosic inhibitors

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Marlous van Dijk ◽  
Peter Rugbjerg ◽  
Yvonne Nygård ◽  
Lisbeth Olsson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stress Response ◽  
Rna Sequencing ◽  
Molecular Mechanisms ◽  
Lignocellulosic Hydrolysate ◽  
Short Term ◽  
Down Regulation ◽  
Time Resolved ◽  
Second Generation Bioethanol ◽  
Short Term Adaptation

Abstract Background The limited tolerance of Saccharomyces cerevisiae to inhibitors is a major challenge in second-generation bioethanol production, and our understanding of the molecular mechanisms providing tolerance to inhibitor-rich lignocellulosic hydrolysates is incomplete. Short-term adaptation of the yeast in the presence of dilute hydrolysate can improve its robustness and productivity during subsequent fermentation. Results We utilized RNA sequencing to investigate differential gene expression in the industrial yeast strain CR01 during short-term adaptation, mimicking industrial conditions for cell propagation. In this first transcriptomic study of short-term adaption of S. cerevisiae to lignocellulosic hydrolysate, we found that cultures respond by fine-tuned up- and down-regulation of a subset of general stress response genes. Furthermore, time-resolved RNA sequencing allowed for identification of genes that were differentially expressed at 2 or more sampling points, revealing the importance of oxidative stress response, thiamin and biotin biosynthesis. furan-aldehyde reductases and specific drug:H+ antiporters, as well as the down-regulation of certain transporter genes. Conclusions These findings provide a better understanding of the molecular mechanisms governing short-term adaptation of S. cerevisiae to lignocellulosic hydrolysate, and suggest new genetic targets for improving fermentation robustness.

scholarly journals Coupling DNA Replication and Spindle Function in Saccharomyces cerevisiae

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3359
Author(s):  
Dimitris Liakopoulos
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Molecular Mechanisms ◽  
Genome Duplication ◽  
Yeast Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Spindle Dynamics ◽  
Eukaryotic Organisms ◽  
Spindle Function

In the yeast Saccharomyces cerevisiae DNA replication and spindle assembly can overlap. Therefore, signaling mechanisms modulate spindle dynamics in order to ensure correct timing of chromosome segregation relative to genome duplication, especially when replication is incomplete or the DNA becomes damaged. This review focuses on the molecular mechanisms that coordinate DNA replication and spindle dynamics, as well as on the role of spindle-dependent forces in DNA repair. Understanding the coupling between genome duplication and spindle function in yeast cells can provide important insights into similar processes operating in other eukaryotic organisms, including humans.

scholarly journals A review. Biochemical and molecular mechanisms in Saccharomyces cerevisiae that are involved in the formation of some volatile compounds in wines

OENO One ◽  
1999 ◽  
Vol 33 (4) ◽  
pp. 195
Author(s):  
Claudio Delfini ◽  
Chiara Cocito ◽  
M. Bonino
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Volatile Compounds ◽  
Scientific Knowledge ◽  
Molecular Mechanisms ◽  
Individual Contribution ◽  
Grape Skins ◽  
Biochemical Genetic ◽  
Biochemical Mechanisms ◽  
The Individual ◽  
Biological Motor

<p style="text-align: justify;">There are evidences that a grape must of a non aromatic vine, not having perfume and revealing by gaschromatographie only some classes of compounds common to the musts of all the vine varieties, can originate a pool of characterizing fragrant substances after contact with the yeast during fermentation. Therefore, despite the scarce scientific knowledge available on biochemical mechanisms involved in <em>Saccharomyces cerevisiae</em> in the formation of a wine aromatic pattern, it can be likely hypothesized that the yeast could be the biological motor of this aromatic transformation. The yeast can act on the compounds of the must with many periplasmic enzymes (estérases, glycosidases, lyases, lipases, proteases, peptidases, pectolytiques) and several are the scientific contributions underlining the existence of an interaction between the yeast and the vine variety in the formation of wine aromatic characteristics. Besides the individual contribution of substances sensorially active, the yeast would contribute to the transformation of unknown varietal aromatic precursors that are in the grape skins and/or musts. The biochemical, genetic and physiological aspects of this transformation still have to be understood. At the end, we have to answer some important questions such as the mutual role that grape and/or yeast enzymes have during and soon after crushing in the liberation of the varietal precursors and in the conversion of these in fragrant compounds.</p>

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