scholarly journals Recruiting a microtubule-binding complex to DNA directs chromosome segregation in budding yeast

2009 ◽  
Vol 11 (9) ◽  
pp. 1116-1120 ◽  
Author(s):  
Soni Lacefield ◽  
Derek T. C. Lau ◽  
Andrew W. Murray
Keyword(s):  
Chromosome Segregation ◽  
Budding Yeast ◽  
Microtubule Binding

scholarly journals The chromosomal passenger complex establishes chromosome biorientation via two parallel localization pathways

2020 ◽  
Author(s):  
Theodor Marsoner ◽  
Poornima Yedavalli ◽  
Chiara Masnovo ◽  
Katrin Schmitzer ◽  
Christopher S. Campbell
Keyword(s):  
Chromosome Segregation ◽  
Budding Yeast ◽  
Small Region ◽  
The Other ◽  
Chromosomal Passenger Complex ◽  
Microtubule Binding ◽  
Chromosome Alignment ◽  
Chromosomal Passenger ◽  
Spindle Microtubules ◽  
Do So

AbstractChromosome biorientation is established by the four-member chromosomal passenger complex (CPC) through phosphorylation of incorrect kinetochore-microtubule attachments. During chromosome alignment, the CPC localizes to the inner centromere, the inner kinetochore and spindle microtubules. Here we show that a small region of the CPC subunit INCENP/Sli15 is required to target the complex to all three of these locations in budding yeast. This region, the SAH, is essential for phosphorylation of outer kinetochore substrates, chromosome segregation, and viability. By restoring the CPC to each of these three locations individually, we found that inner centromere localization is sufficient to establish chromosome biorientation and viability independently of the other two targeting mechanisms. Remarkably, although neither the inner kinetochore nor microtubule binding activities was able to rescue viability individually, they were able to do so when combined. We have therefore identified two parallel pathways by which the CPC can promote chromosome biorientation and proper completion of mitosis.

scholarly journals Structural and dynamic mechanisms of CBF3-guided centromeric nucleosome formation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ruifang Guan ◽  
Tengfei Lian ◽  
Bing-Rui Zhou ◽  
Emily He ◽  
Carl Wu ◽  
...  
Keyword(s):  
Dna Sequence ◽  
Chromosome Segregation ◽  
Budding Yeast ◽  
Dna Conformation ◽  
Dependent Manner ◽  
Dynamic Interactions ◽  
Nucleosome Core ◽  
Dynamic Mechanisms ◽  
Nucleosome Formation ◽  
Core Histones

AbstractAccurate chromosome segregation relies on the specific centromeric nucleosome–kinetochore interface. In budding yeast, the centromere CBF3 complex guides the deposition of CENP-A, an H3 variant, to form the centromeric nucleosome in a DNA sequence-dependent manner. Here, we determine the structures of the centromeric nucleosome containing the native CEN3 DNA and the CBF3core bound to the canonical nucleosome containing an engineered CEN3 DNA. The centromeric nucleosome core structure contains 115 base pair DNA including a CCG motif. The CBF3core specifically recognizes the nucleosomal CCG motif through the Gal4 domain while allosterically altering the DNA conformation. Cryo-EM, modeling, and mutational studies reveal that the CBF3core forms dynamic interactions with core histones H2B and CENP-A in the CEN3 nucleosome. Our results provide insights into the structure of the budding yeast centromeric nucleosome and the mechanism of its assembly, which have implications for analogous processes of human centromeric nucleosome formation.

scholarly journals Temperature-Dependent Modulation of Chromosome Segregation in msh4 Mutants of Budding Yeast

PLoS ONE ◽  
2009 ◽  
Vol 4 (10) ◽  
pp. e7284 ◽  
Author(s):  
Andrew Chi-Ho Chan ◽  
Rhona H. Borts ◽  
Eva Hoffmann
Keyword(s):  
Chromosome Segregation ◽  
Budding Yeast ◽  
Temperature Dependent

scholarly journals Genes Involved in Sister Chromatid Separation and Segregation in the Budding Yeast Saccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 453-470
Author(s):  
Sue Biggins ◽  
Needhi Bhalla ◽  
Amy Chang ◽  
Dana L Smith ◽  
Andrew W Murray
Keyword(s):  
Chromosome Segregation ◽  
Sister Chromatid ◽  
Mitotic Spindle ◽  
Budding Yeast ◽  
Temperature Sensitive ◽  
Chromosome Behavior ◽  
Yeast Saccharomyces Cerevisiae ◽  
Sister Chromatids ◽  
Marked Chromosome ◽  
Sister Chromatid Separation

Abstract Accurate chromosome segregation requires the precise coordination of events during the cell cycle. Replicated sister chromatids are held together while they are properly attached to and aligned by the mitotic spindle at metaphase. At anaphase, the links between sisters must be promptly dissolved to allow the mitotic spindle to rapidly separate them to opposite poles. To isolate genes involved in chromosome behavior during mitosis, we microscopically screened a temperature-sensitive collection of budding yeast mutants that contain a GFP-marked chromosome. Nine LOC (loss of cohesion) complementation groups that do not segregate sister chromatids at anaphase were identified. We cloned the corresponding genes and performed secondary tests to determine their function in chromosome behavior. We determined that three LOC genes, PDS1, ESP1, and YCS4, are required for sister chromatid separation and three other LOC genes, CSE4, IPL1, and SMT3, are required for chromosome segregation. We isolated alleles of two genes involved in splicing, PRP16 and PRP19, which impair α-tubulin synthesis thus preventing spindle assembly, as well as an allele of CDC7 that is defective in DNA replication. We also report an initial characterization of phenotypes associated with the SMT3/SUMO gene and the isolation of WSS1, a high-copy smt3 suppressor.

scholarly journals Yeast Kinetochores Do Not Stabilize Stu2p-dependent Spindle Microtubule Dynamics

2003 ◽  
Vol 14 (10) ◽  
pp. 4181-4195 ◽  
Author(s):  
Chad G. Pearson ◽  
Paul S. Maddox ◽  
Ted R. Zarzar ◽  
E.D. Salmon ◽  
Kerry Bloom
Keyword(s):  
Chromosome Segregation ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Regulatory Mechanism ◽  
Metaphase Plate ◽  
Microtubule Dynamics ◽  
Spindle Microtubule ◽  
Microtubule Binding ◽  
Microtubule Stabilization ◽  
Kinetochore Function

The interaction of kinetochores with dynamic microtubules during mitosis is essential for proper centromere motility, congression to the metaphase plate, and subsequent anaphase chromosome segregation. Budding yeast has been critical in the discovery of proteins necessary for this interaction. However, the molecular mechanism for microtubule–kinetochore interactions remains poorly understood. Using live cell imaging and mutations affecting microtubule binding proteins and kinetochore function, we identify a regulatory mechanism for spindle microtubule dynamics involving Stu2p and the core kinetochore component, Ndc10p. Depleting cells of the microtubule binding protein Stu2p reduces kinetochore microtubule dynamics. Centromeres remain under tension but lack motility. Thus, normal microtubule dynamics are not required to maintain tension at the centromere. Loss of the kinetochore (ndc10-1, ndc10-2, and ctf13-30) does not drastically affect spindle microtubule turnover, indicating that Stu2p, not the kinetochore, is the foremost governor of microtubule dynamics. Disruption of kinetochore function with ndc10-1 does not affect the decrease in microtubule turnover in stu2 mutants, suggesting that the kinetochore is not required for microtubule stabilization. Remarkably, a partial kinetochore defect (ndc10-2) suppresses the decreased spindle microtubule turnover in the absence of Stu2p. These results indicate that Stu2p and Ndc10p differentially function in controlling kinetochore microtubule dynamics necessary for centromere movements.

scholarly journals The kinetoplastid kinetochore protein KKT4 is an unconventional microtubule tip–coupling protein

2018 ◽  
Vol 217 (11) ◽  
pp. 3886-3900 ◽  
Author(s):  
Aida Llauró ◽  
Hanako Hayashi ◽  
Megan E. Bailey ◽  
Alex Wilson ◽  
Patryk Ludzia ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Binding Activity ◽  
Significant Similarity ◽  
Load Bearing ◽  
Kinetochore Protein ◽  
Microtubule Binding ◽  
Binding Domains ◽  
Microtubule Binding Domain ◽  
Coupling Protein

Kinetochores are multiprotein machines that drive chromosome segregation by maintaining persistent, load-bearing linkages between chromosomes and dynamic microtubule tips. Kinetochores in commonly studied eukaryotes bind microtubules through widely conserved components like the Ndc80 complex. However, in evolutionarily divergent kinetoplastid species such as Trypanosoma brucei, which causes sleeping sickness, the kinetochores assemble from a unique set of proteins lacking homology to any known microtubule-binding domains. Here, we show that the T. brucei kinetochore protein KKT4 binds directly to microtubules and maintains load-bearing attachments to both growing and shortening microtubule tips. The protein localizes both to kinetochores and to spindle microtubules in vivo, and its depletion causes defects in chromosome segregation. We define a microtubule-binding domain within KKT4 and identify several charged residues important for its microtubule-binding activity. Thus, despite its lack of significant similarity to other known microtubule-binding proteins, KKT4 has key functions required for driving chromosome segregation. We propose that it represents a primary element of the kinetochore–microtubule interface in kinetoplastids.

scholarly journals Parts list for a microtubule depolymerising kinesin

2018 ◽  
Vol 46 (6) ◽  
pp. 1665-1672 ◽  
Author(s):  
Claire T. Friel ◽  
Julie P. Welburn
Keyword(s):  
Chromosome Segregation ◽  
Molecular Motors ◽  
Neuronal Development ◽  
Current Understanding ◽  
Cellular Functions ◽  
Microtubule Cytoskeleton ◽  
Microtubule Binding ◽  
Large Group ◽  
Kinesin Superfamily ◽  
Different Parts

The Kinesin superfamily is a large group of molecular motors that use the turnover of ATP to regulate their interaction with the microtubule cytoskeleton. The coupled relationship between nucleotide turnover and microtubule binding is harnessed in various ways by these motors allowing them to carry out a variety of cellular functions. The Kinesin-13 family is a group of specialist microtubule depolymerising motors. Members of this family use their microtubule destabilising activity to regulate processes such as chromosome segregation, maintenance of cilia and neuronal development. Here, we describe the current understanding of the structure of this family of kinesins and the role different parts of these proteins play in their microtubule depolymerisation activity and in the wider function of this family of kinesins.

scholarly journals Differential requirement for Bub1 and Bub3 in regulation of meiotic versus mitotic chromosome segregation

2020 ◽  
Vol 219 (4) ◽  
Author(s):  
Gisela Cairo ◽  
Anne M. MacKenzie ◽  
Soni Lacefield
Keyword(s):  
Chromosome Segregation ◽  
Protein Phosphatase ◽  
Mitotic Chromosome ◽  
Budding Yeast ◽  
Meiotic Chromosome ◽  
Protein Phosphatase 1 ◽  
Aurora B ◽  
Chromosome Missegregation ◽  
Anaphase Onset ◽  
Spindle Microtubules

Accurate chromosome segregation depends on the proper attachment of kinetochores to spindle microtubules before anaphase onset. The Ipl1/Aurora B kinase corrects improper attachments by phosphorylating kinetochore components and so releasing aberrant kinetochore–microtubule interactions. The localization of Ipl1 to kinetochores in budding yeast depends upon multiple pathways, including the Bub1–Bub3 pathway. We show here that in meiosis, Bub3 is crucial for correction of attachment errors. Depletion of Bub3 results in reduced levels of kinetochore-localized Ipl1 and concomitant massive chromosome missegregation caused by incorrect chromosome–spindle attachments. Depletion of Bub3 also results in shorter metaphase I and metaphase II due to premature localization of protein phosphatase 1 (PP1) to kinetochores, which antagonizes Ipl1-mediated phosphorylation. We propose a new role for the Bub1–Bub3 pathway in maintaining the balance between kinetochore localization of Ipl1 and PP1, a balance that is essential for accurate meiotic chromosome segregation and timely anaphase onset.

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