scholarly journals A role for the fission yeast Rqh1 helicase in chromosome segregation

2005 ◽  
Vol 118 (24) ◽  
pp. 5777-5784 ◽  
Author(s):  
T. Z. Win
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation

scholarly journals Novel Genes Required for Meiotic Chromosome Segregation Are Identified by a High-Throughput Knockout Screen in Fission Yeast

2005 ◽  
Vol 15 (18) ◽  
pp. 1663-1669 ◽  
Author(s):  
Juraj Gregan ◽  
Peter K. Rabitsch ◽  
Benjamin Sakem ◽  
Ortansa Csutak ◽  
Vitaly Latypov ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
High Throughput ◽  
Meiotic Chromosome ◽  
Novel Genes

scholarly journals A microtubule polymerase cooperates with the kinesin-6 motor and a microtubule cross-linker to promote bipolar spindle assembly in the absence of kinesin-5 and kinesin-14 in fission yeast

2017 ◽  
Vol 28 (25) ◽  
pp. 3647-3659 ◽  
Author(s):  
Masashi Yukawa ◽  
Tomoki Kawakami ◽  
Masaki Okazaki ◽  
Kazunori Kume ◽  
Ngang Heok Tang ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Spindle Pole Body ◽  
Spindle Assembly ◽  
Spindle Pole ◽  
Temperature Sensitive ◽  
Bipolar Spindle ◽  
Pole Body ◽  
Cross Linker ◽  
Spindle Elongation

Accurate chromosome segregation relies on the bipolar mitotic spindle. In many eukaryotes, spindle formation is driven by the plus-end–directed motor kinesin-5 that generates outward force to establish spindle bipolarity. Its inhibition leads to the emergence of monopolar spindles with mitotic arrest. Intriguingly, simultaneous inactivation of the minus-end–directed motor kinesin-14 restores spindle bipolarity in many systems. Here we show that in fission yeast, three independent pathways contribute to spindle bipolarity in the absence of kinesin-5/Cut7 and kinesin-14/Pkl1. One is kinesin-6/Klp9 that engages with spindle elongation once short bipolar spindles assemble. Klp9 also ensures the medial positioning of anaphase spindles to prevent unequal chromosome segregation. Another is the Alp7/TACC-Alp14/TOG microtubule polymerase complex. Temperature-sensitive alp7cut7pkl1 mutants are arrested with either monopolar or very short spindles. Forced targeting of Alp14 to the spindle pole body is sufficient to render alp7cut7pkl1 triply deleted cells viable and promote spindle assembly, indicating that Alp14-mediated microtubule polymerization from the nuclear face of the spindle pole body could generate outward force in place of Cut7 during early mitosis. The third pathway involves the Ase1/PRC1 microtubule cross-linker that stabilizes antiparallel microtubules. Our study, therefore, unveils multifaceted interplay among kinesin-dependent and -independent pathways leading to mitotic bipolar spindle assembly.

scholarly journals Immediate visualization of recombination events and chromosome segregation defects in fission yeast meiosis

Chromosoma ◽  
2019 ◽  
Vol 128 (3) ◽  
pp. 385-396 ◽  
Author(s):  
Dmitriy Li ◽  
Marianne Roca ◽  
Raif Yuecel ◽  
Alexander Lorenz
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Yeast Meiosis

scholarly journals Fission yeast Hrp1, a chromodomain ATPase, is required for proper chromosome segregation and its overexpression interferes with chromatin condensation

2000 ◽  
Vol 28 (9) ◽  
pp. 2004-2011 ◽  
Author(s):  
E. J. Yoo ◽  
Y. H. Jin ◽  
Y. K. Jang ◽  
P. Bjerling ◽  
M. Tabish ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Chromatin Condensation

scholarly journals csi2p modulates microtubule dynamics and organizes the bipolar spindle for chromosome segregation

2014 ◽  
Vol 25 (24) ◽  
pp. 3900-3908 ◽  
Author(s):  
Judite Costa ◽  
Chuanhai Fu ◽  
V. Mohini Khare ◽  
Phong T. Tran
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Spindle Assembly Checkpoint ◽  
Microtubule Dynamics ◽  
High Rate ◽  
Spindle Formation ◽  
Bipolar Spindle ◽  
Eukaryotic Chromosome ◽  
Relative Contribution ◽  
Multiple Phenotypes

Proper chromosome segregation is of paramount importance for proper genetic inheritance. Defects in chromosome segregation can lead to aneuploidy, which is a hallmark of cancer cells. Eukaryotic chromosome segregation is accomplished by the bipolar spindle. Additional mechanisms, such as the spindle assembly checkpoint and centromere positioning, further help to ensure complete segregation fidelity. Here we present the fission yeast csi2+. csi2p localizes to the spindle poles, where it regulates mitotic microtubule dynamics, bipolar spindle formation, and subsequent chromosome segregation. csi2 deletion (csi2Δ) results in abnormally long mitotic microtubules, high rate of transient monopolar spindles, and subsequent high rate of chromosome segregation defects. Because csi2Δ has multiple phenotypes, it enables estimates of the relative contribution of the different mechanisms to the overall chromosome segregation process. Centromere positioning, microtubule dynamics, and bipolar spindle formation can all contribute to chromosome segregation. However, the major determinant of chromosome segregation defects in fission yeast may be microtubule dynamic defects.

scholarly journals Inverted meiosis: an alternative way of chromosome segregation for reproduction

2020 ◽  
Vol 52 (7) ◽  
pp. 702-707 ◽  
Author(s):  
Wenzhu Li ◽  
Xiangwei He
Keyword(s):  
Dna Replication ◽  
Fission Yeast ◽  
Chromosome Segregation ◽  
Chromosome Structure ◽  
Adaptive Strategy ◽  
Homologous Chromosomes ◽  
Working Model ◽  
Sister Chromatids ◽  
Holocentric Chromosome ◽  
Inverted Order

Abstract Canonical meiosis is characterized by two sequential rounds of nuclear divisions following one round of DNA replication—reductional segregation of homologous chromosomes during the first division and equational segregation of sister chromatids during the second division. Meiosis in an inverted order of two nuclear divisions—inverted meiosis has been observed in several species with holocentromeres as an adaptive strategy to overcome the obstacle in executing a canonical meiosis due to the holocentric chromosome structure. Recent findings of co-existence of inverted and canonical meiosis in two monocentric organisms, human and fission yeast, suggested that inverted meiosis could be common and also lead to the puzzle regarding the mechanistic feasibility for executing two meiosis programs simultaneously. Here, we discuss apparent conflicts for concurrent canonical meiosis and inverted meiosis. Furthermore, we attempt to provide a working model that may be compatible for both forms of meiosis.

scholarly journals Spindle checkpoint activation at meiosis I advances anaphase II onset via meiosis-specific APC/C regulation

2008 ◽  
Vol 182 (2) ◽  
pp. 277-288 ◽  
Author(s):  
Ayumu Yamamoto ◽  
Kenji Kitamura ◽  
Daisuke Hihara ◽  
Yukinobu Hirose ◽  
Satoshi Katsuyama ◽  
...  
Keyword(s):  
Protein Degradation ◽  
Fission Yeast ◽  
Chromosome Segregation ◽  
Spindle Assembly Checkpoint ◽  
Related Factor ◽  
Anaphase Promoting Complex ◽  
Checkpoint Activation ◽  
Anaphase Onset ◽  
Yeast Meiosis ◽  
Meiosis I

During mitosis, the spindle assembly checkpoint (SAC) inhibits the Cdc20-activated anaphase-promoting complex/cyclosome (APC/CCdc20), which promotes protein degradation, and delays anaphase onset to ensure accurate chromosome segregation. However, the SAC function in meiotic anaphase regulation is poorly understood. Here, we examined the SAC function in fission yeast meiosis. As in mitosis, a SAC factor, Mad2, delayed anaphase onset via Slp1 (fission yeast Cdc20) when chromosomes attach to the spindle improperly. However, when the SAC delayed anaphase I, the interval between meiosis I and II shortened. Furthermore, anaphase onset was advanced and the SAC effect was reduced at meiosis II. The advancement of anaphase onset depended on a meiosis-specific, Cdc20-related factor, Fzr1/Mfr1, which contributed to anaphase cyclin decline and anaphase onset and was inefficiently inhibited by the SAC. Our findings show that impacts of SAC activation are not confined to a single division at meiosis due to meiosis-specific APC/C regulation, which has probably been evolved for execution of two meiotic divisions.

scholarly journals Mutation of histone H3 serine 86 disrupts GATA factor Ams2 expression and precise chromosome segregation in fission yeast

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Kim Kiat Lim ◽  
Terenze Yao Rui Ong ◽  
Yue Rong Tan ◽  
Eugene Guorong Yang ◽  
Bingbing Ren ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Histone H3 ◽  
Gata Factor

scholarly journals Cohesins Determine the Attachment Manner of Kinetochores to Spindle Microtubules at Meiosis I in Fission Yeast

2003 ◽  
Vol 23 (11) ◽  
pp. 3965-3973 ◽  
Author(s):  
Shihori Yokobayashi ◽  
Masayuki Yamamoto ◽  
Yoshinori Watanabe
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Sister Chromatid ◽  
Specific Requirement ◽  
Spindle Poles ◽  
Chromatid Cohesion ◽  
Spindle Microtubules ◽  
Yeast Meiosis ◽  
Meiosis I ◽  
Random Division

ABSTRACT During mitosis, sister kinetochores attach to microtubules that extend to opposite spindle poles (bipolar attachment) and pull the chromatids apart at anaphase (equational segregation). A multisubunit complex called cohesin, including Rad21/Scc1, plays a crucial role in sister chromatid cohesion and equational segregation at mitosis. Meiosis I differs from mitosis in having a reductional pattern of chromosome segregation, in which sister kinetochores are attached to the same spindle (monopolar attachment). During meiosis, Rad21/Scc1 is largely replaced by its meiotic counterpart, Rec8. If Rec8 is inactivated in fission yeast, meiosis I is shifted from reductional to equational division. However, the reason rec8Δ cells undergo equational rather than random division has not been clarified; therefore, it has been unclear whether equational segregation is due to a loss of cohesin in general or to a loss of a specific requirement for Rec8. We report here that the equational segregation at meiosis I depends on substitutive Rad21, which relocates to the centromeres if Rec8 is absent. Moreover, we demonstrate that even if sufficient amounts of Rad21 are transferred to the centromeres at meiosis I, thereby establishing cohesion at the centromeres, rec8Δ cells never recover monopolar attachment but instead secure bipolar attachment. Thus, Rec8 and Rad21 define monopolar and bipolar attachment, respectively, at meiosis I. We conclude that cohesin is a crucial determinant of the attachment manner of kinetochores to the spindle microtubules at meiosis I in fission yeast.

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