Design Features of a Mitotic Spindle: Balancing Tension and Compression at a Single Microtubule Kinetochore Interface in Budding Yeast

Bouck, David C.; Joglekar, Ajit P.; Bloom, Kerry

doi:10.1146/annurev.genet.42.110807.091620

Cited by 54 publications

(54 citation statements)

References 147 publications

(159 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Indeed, recent analysis of yeast and Drosophila CENH3 nucleosomes show that they wrap DNA into a righthanded configuration, which is structurally incompatible with canonical octameric organization (33,34). The right-handed direction of the DNA wrap dictated by tetrameric nucleosomes would be the same as the direction of the twist of double helix, providing a plausible solution for how centromeres are able to provide a solid structural basis for the kinetochore (35).…”

mentioning

confidence: 99%

Tetrameric organization of vertebrate centromeric nucleosomes

Dimitriadis

Weber

Gill

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Mitosis ensures equal genome segregation in the eukaryotic lineage. This process is facilitated by microtubule attachment to each chromosome via its centromere. In centromeres, canonical histone H3 is replaced in nucleosomes by a centromere-specific histone H3 variant (CENH3), providing the unique epigenetic signature required for microtubule binding. Due to recent findings of alternative CENH3 nucleosomal forms in invertebrate centromeres, it has been debated whether the classical octameric nucleosomal arrangement of two copies of CENH3, H4, H2A, and H2B forms the basis of the vertebrate centromere. To address this question directly, we examined CENH3 [centromere protein A (CENP-A)] nucleosomal organization in human cells, using a combination of nucleosome component analysis, atomic force microscopy (AFM), and immunoelectron microscopy (immuno-EM). We report that native CENP-A nucleosomes contain centromeric alpha satellite DNA, have equimolar amounts of H2A, H2B, CENP-A, and H4, and bind kinetochore proteins. These nucleosomes, when measured by AFM, yield one-half the dimensions of canonical octameric nucleosomes. Using immuno-EM, we find that one copy of CENP-A, H2A, H2B, and H4 coexist in CENP-A nucleosomes, in which internal C-terminal domains are accessible. Our observations indicate that CENP-A nucleosomes are organized as asymmetric heterotypic tetramers, rather than canonical octamers. Such altered nucleosomes form a chromatin fiber with distinct folding characteristics, which we utilize to discriminate tetramers directly within bulk chromatin. We discuss implications of our observations in the context of universal epigenetic and mechanical requirements for functional centromeres.alternative nucleosomes | cell division | histone variant | regional centromeres E ach eukaryotic chromosome has a centromere, which serves as the sole attachment point for spindle microtubules during mitosis (1). Sister centromeres undergo a distinct phase change from independent discrete spots in the interphase nucleus to a paired constriction on mitotic chromosomes. At the base of the constriction, centromeric DNA is packaged within variant nucleosomes composed of a centromere-specific histone H3 (CENH3). In metazoans, centromeric DNA alone is insufficient to dictate centromere location, as evidenced by the formation of satellite-free neocentromeres (2, 3). That a common epigenetic identity prevails can be deduced from a number of studies spanning evolutionary, biochemical, cytological, genetic, and genomic methods (4-22), all of which pinpoint CENH3 as the key epigenetic marker for active centromeres in eukaryotes.Another general feature of CENH3 nucleosomes is that they must provide a stable foundation for kinetochore proteins (23), while still allowing displacement during DNA replication. Studies investigating structural features of centromeric chromatin that contribute to its function have reported that it is refractory to nuclease digestion (24-26) and topologically distinctive (27,28). Direct examinations of Drosophila...

show abstract

mentioning

confidence: 99%

Tetrameric organization of vertebrate centromeric nucleosomes

Dimitriadis

Weber

Gill

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…16 This stoichiometry is consistent with the limited number of microtubules in yeast, restricting the association of a single kinetochore microtubule with each chromosome. 17 The amount of Cse4 in the nucleus is tightly regulated by its rapid turnover via the ubiquitin mediated protein degradation pathway. 18,19 Only Cse4 associated with a centromere is stable whereas that associated elsewhere with chromatin is subject to degradation.…”

Section: The Paradox Between the Strict Cellular Economy Of Cse4 And mentioning

confidence: 99%

Association of a centromere specific nucleosome with the yeast plasmid partitioning locus

Jayaram

2011

Mobile Genetic Elements

View full text Add to dashboard Cite

“…6 In addition, SPBs organize astral MTs that orient the ~2 μm-long preanaphase spindle toward the bud neck. 7 In S. cerevisiae, the assembly of a spindle proceeds normally, even in the presence of DNA replication delays or blocks.…”

Section: Introductionmentioning

confidence: 99%

“…7 In S. cerevisiae, the assembly of a spindle proceeds normally, even in the presence of DNA replication delays or blocks. 6 Separation of side-by-side SPBs is an MT-dependent process requiring MT motors and MT-associated proteins (MAPs). At least one kinesin -5, 8 Cin8p or Kip1, is essential to power SPB separation, presumably by sliding antiparallel MTs.…”

Section: Introductionmentioning

confidence: 99%

“…The kinesin-14 Kar3p antagonizes this outward force while paradoxically helping stabilize the midzone. 6,[9][10][11][12] In addition, Cin8p controls kinetochore MT length, forcing chromosome congression. 13 Among the yeast MAPs, Ase1p is crucial for the integrity of the midzone, 14,15 with further contributions by the yeast EB1, Bim1p and the yeast CLIP170, Bik1p.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation