scholarly journals Mes1 controls the meiosis I to meiosis II transition by distinctly regulating the anaphase-promoting complex/cyclosome coactivators Fzr1/Mfr1 and Slp1 in fission yeast

2011 ◽  
Vol 22 (9) ◽  
pp. 1486-1494 ◽  
Author(s):  
Yuu Kimata ◽  
Kenji Kitamura ◽  
Nicola Fenner ◽  
Hiroyuki Yamano
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Specific Protein ◽  
Eukaryotic Cells ◽  
Yeast Genome ◽  
Anaphase Promoting Complex ◽  
Specialized Form ◽  
Competitive Substrate ◽  
Yeast Meiosis ◽  
Meiosis I

Meiosis is a specialized form of cell division generating haploid gametes and is dependent upon protein ubiquitylation by the anaphase-promoting complex/cyclosome (APC/C). Accurate control of the APC/C during meiosis is important in all eukaryotic cells and is in part regulated by the association of coactivators and inhibitors. We previously showed that the fission yeast meiosis-specific protein Mes1 binds to a coactivator and inhibits APC/C; however, regulation of the Mes1-mediated APC/C inhibition remains elusive. Here we show how Mes1 distinctively regulates different forms of the APC/C. We study all the coactivators present in the yeast genome and find that only Slp1/Cdc20 is essential for meiosis I progression. However, Fzr1/Mfr1 is a critical target for Mes1 inhibition because fzr1Δ completely rescues the defect on the meiosis II entry in mes1Δ cells. Furthermore, cell-free studies suggest that Mes1 behaves as a pseudosubstrate for Fzr1/Mfr1 but works as a competitive substrate for Slp1. Intriguingly, mutations in the D-box or KEN-box of Mes1 increase its recognition as a substrate by Fzr1, but not by Slp1. Thus Mes1 interacts with two coactivators in a different way to control the activity of the APC/C required for the meiosis I/meiosis II transition.

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 Paired arrangement of kinetochores together with microtubule pivoting and dynamics drive kinetochore capture in meiosis I

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Gheorghe Cojoc ◽  
Ana-Maria Florescu ◽  
Alexander Krull ◽  
Anna H. Klemm ◽  
Nenad Pavin ◽  
...  
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
General Feature ◽  
Protein Complexes ◽  
Spindle Pole ◽  
Single Object ◽  
Homologous Chromosomes ◽  
Angular Movement ◽  
Spindle Microtubules ◽  
Meiosis I

Abstract Kinetochores are protein complexes on the chromosomes, whose function as linkers between spindle microtubules and chromosomes is crucial for proper cell division. The mechanisms that facilitate kinetochore capture by microtubules are still unclear. In the present study, we combine experiments and theory to explore the mechanisms of kinetochore capture at the onset of meiosis I in fission yeast. We show that kinetochores on homologous chromosomes move together, microtubules are dynamic and pivot around the spindle pole, and the average capture time is 3–4 minutes. Our theory describes paired kinetochores on homologous chromosomes as a single object, as well as angular movement of microtubules and their dynamics. For the experimentally measured parameters, the model reproduces the measured capture kinetics and shows that the paired configuration of kinetochores accelerates capture, whereas microtubule pivoting and dynamics have a smaller contribution. Kinetochore pairing may be a general feature that increases capture efficiency in meiotic cells.

scholarly journals Separase cleaves the kinetochore protein Meikin to direct the meiosis I/II transition

2020 ◽  
Author(s):  
Nolan K Maier ◽  
Jun Ma ◽  
Michael A Lampson ◽  
Iain M Cheeseman
Keyword(s):  
Cell Division ◽  
Germ Cells ◽  
Molecular Switch ◽  
Specific Protein ◽  
Cleavage Product ◽  
Regulatory Mechanisms ◽  
Kinetochore Protein ◽  
Chromosome Alignment ◽  
Activity State ◽  
Meiosis I

SummaryTo generate haploid gametes, germ cells undergo two consecutive meiotic divisions requiring key changes to the cell division machinery. Here, we explore the regulatory mechanisms that differentially control meiotic events. We demonstrate that the protease Separase rewires key cell division processes at the meiosis I/II transition by cleaving the meiosis-specific protein Meikin. In contrast to cohesin, which is inactivated by Separase proteolysis, cleaved Meikin remains functional, but results in a distinct activity state. Full-length Meikin and the C-terminal Meikin Separase-cleavage product both localize to kinetochores, bind to Plk1 kinase, and promote Rec8 cleavage, but our results reveal distinct roles for these proteins in controlling meiosis. Mutations that prevent Meikin cleavage or that conditionally inactivate Meikin at anaphase I both result in defective meiosis II chromosome alignment. Thus, Separase cleavage of Meikin creates an irreversible molecular switch to rewire the cell division machinery at the meiosis I/II transition.

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.

Live observation of fission yeast meiosis in recombination-deficient mutants

2001 ◽  
Vol 114 (15) ◽  
pp. 2843-2853 ◽  
Author(s):  
Monika Molnar ◽  
Jürg Bähler ◽  
Jürg Kohli ◽  
Yasushi Hiraoka
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Meiotic Division ◽  
Chiasma Formation ◽  
Homologous Chromosomes ◽  
Yeast Meiosis ◽  
Mutant Cells ◽  
Random Level ◽  
Meiosis I ◽  
Chromosome Disjunction

Regular segregation of homologous chromosomes during meiotic divisions is essential for the generation of viable progeny. In recombination-proficient organisms, chromosome disjunction at meiosis I generally occurs by chiasma formation between the homologs (chiasmate meiosis). We have studied meiotic stages in living rec8 and rec7 mutant cells of fission yeast, with special attention to prophase and the first meiotic division. Both rec8 and rec7 are early recombination mutants, and in rec7 mutants, chromosome segregation at meiosis I occurs without any recombination (achiasmate meiosis). Both mutants showed distinct irregularities in nuclear prophase movements. Additionally, rec7 showed an extended first division of variable length and with single chromosomes changing back and forth between the cell poles. Two other early recombination deficient mutants (rec14 and rec15) showed very similar phenotypes to rec7 during the first meiotic division, and the fidelity of achiasmate chromosome segregation slightly exceeded the expected random level. We discuss possible regulatory mechanisms of fission yeast to deal with achiasmate chromosome segregation.

Fission yeast mfr1 activates APC and coordinates meiotic nuclear division with sporulation

2001 ◽  
Vol 114 (11) ◽  
pp. 2135-2143 ◽  
Author(s):  
Miguel A. Blanco ◽  
Laetitia Pelloquin ◽  
Sergio Moreno
Keyword(s):  
Kinase Activity ◽  
Nuclear Division ◽  
Mitotic Cell ◽  
Specific Protein ◽  
Mitotic Exit ◽  
Spore Formation ◽  
Anaphase Promoting Complex ◽  
Cdc2 Kinase ◽  
Developmental Program ◽  
Yeast Meiosis

Meiosis is the developmental program by which sexually reproducing diploid organisms generate haploid gametes. In yeast, meiosis is followed by spore morphogenesis. These two events are normally coordinated in such a way that spore formation is dependent upon completion of the meiotic nuclear divisions. Here we describe a meiosis-specific protein, mfr1, that is involved in this coordination. mfr1 is an activator of the anaphase-promoting complex (APC), which is necessary for the rapid degradation of the cdc13 cyclin at the end of meiosis II, prior to the formation of spores. An mfr1 null mutant completes meiosis II but remains with high levels of cdc13 and cdc2 kinase activity and has considerably delayed spore formation. By analogy with the mitotic cell cycle, where proteolysis and inactivation of cdc2 kinase are necessary to trigger mitotic exit and cytokinesis, we propose that at the end of meiosis rapid and timely proteolysis of cyclins is required to switch on the differentiation program that eventually leads to the formation of haploid gametes.

scholarly journals Plo1 Kinase Recruitment to the Spindle Pole Body and Its Role in Cell Division inSchizosaccharomyces pombe

1999 ◽  
Vol 10 (8) ◽  
pp. 2771-2785 ◽  
Author(s):  
Daniel P. Mulvihill ◽  
Janni Petersen ◽  
Hiroyuki Ohkura ◽  
David M. Glover ◽  
Iain M. Hagan
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Multiple Roles ◽  
Anaphase Promoting Complex ◽  
Pole Body ◽  
Early Anaphase ◽  
Anaphase B ◽  
Mitotic Event

Polo kinases execute multiple roles during cell division. The fission yeast polo related kinase Plo1 is required to assemble the mitotic spindle, the prophase actin ring that predicts the site for cytokinesis and for septation after the completion of mitosis ( Ohkuraet al., 1995 ; Bahler et al., 1998 ). We show that Plo1 associates with the mitotic but not interphase spindle pole body (SPB). SPB association of Plo1 is the earliest fission yeast mitotic event recorded to date. SPB association is strong from mitotic commitment to early anaphase B, after which the Plo1 signal becomes very weak and finally disappears upon spindle breakdown. SPB association of Plo1 requires mitosis-promoting factor (MPF) activity, whereas its disassociation requires the activity of the anaphase-promoting complex. The stf1.1 mutation bypasses the usual requirement for the MPF activator Cdc25 ( Hudson et al., 1990 ). Significantly, Plo1 associates inappropriately with the interphase SPB of stf1.1 cells. These data are consistent with the emerging theme from many systems that polo kinases participate in the regulation of MPF to determine the timing of commitment to mitosis and may indicate that pole association is a key aspect of Plo1 function. Plo1 does not associate with the SPB when septation is inappropriately driven by deregulation of the Spg1 pathway and remains SPB associated if septation occurs in the presence of a spindle. Thus, neither Plo1 recruitment to nor its departure from the SPB are required for septation; however, overexpression ofplo1+activates the Spg1 pathway and causes transient Cdc7 recruitment to the SPB and multiple rounds of septation.

scholarly journals Reconstruction of the Kinetochore during Meiosis in Fission Yeast Schizosaccharomyces pombe

2006 ◽  
Vol 17 (12) ◽  
pp. 5173-5184 ◽  
Author(s):  
Aki Hayashi ◽  
Haruhiko Asakawa ◽  
Tokuko Haraguchi ◽  
Yasushi Hiraoka
Keyword(s):  
Fission Yeast ◽  
Specific Protein ◽  
Living Cells ◽  
The Other ◽  
Structural Basis ◽  
Meiotic Behavior ◽  
Late Prophase ◽  
Centromere Proteins ◽  
Protein Components ◽  
Meiosis I

During the transition from mitosis to meiosis, the kinetochore undergoes significant reorganization, switching from a bipolar to a monopolar orientation. To examine the centromere proteins that are involved in fundamental reorganization in meiosis, we observed the localization of 22 mitotic and 2 meiotic protein components of the kinetochore during meiosis in living cells of the fission yeast. We found that the 22 mitotic proteins can be classified into three groups: the Mis6-like group, the NMS (Ndc80-Mis12-Spc7) group, and the DASH group, based on their meiotic behavior. Mis6-like group proteins remain at the centromere throughout meiosis. NMS group proteins disappear from the centromere at the onset of meiosis and reappear at the centromere in two steps in late prophase. DASH group proteins appear shortly before metaphase of meiosis I. These observations suggest that Mis6-like group proteins constitute the structural basis of the centromere and that the NMS and DASH group proteins reassemble to establish the functional metaphase kinetochore. On the other hand, the meiosis-specific protein Moa1, which plays an important role in forming the meiotic monopolar kinetochore, is loaded onto the centromere significantly earlier than the NMS group, whereas another meiosis-specific protein, Sgo1, is loaded at times similar to the NMS group.

Pcp1/pericentrin controls the SPB number in fission yeast meiosis and ploidy homeostasis

2021 ◽  
Vol 221 (1) ◽  
Author(s):  
Qian Zhu ◽  
Zhaodi Jiang ◽  
Xiangwei He
Keyword(s):  
Cell Division ◽  
Sexual Reproduction ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Bipolar Spindle ◽  
Pole Body ◽  
Yeast Meiosis ◽  
Quantity Control

During sexual reproduction, the zygote must inherit exactly one centrosome (spindle pole body [SPB] in yeasts) from the gametes, which then duplicates and assembles a bipolar spindle that supports the subsequent cell division. Here, we show that in the fission yeast Schizosaccharomyces pombe, the fusion of SPBs from the gametes is blocked in polyploid zygotes. As a result, the polyploid zygotes cannot proliferate mitotically and frequently form supernumerary SPBs during subsequent meiosis, which leads to multipolar nuclear divisions and the generation of extra spores. The blockage of SPB fusion is caused by persistent SPB localization of Pcp1, which, in normal diploid zygotic meiosis, exhibits a dynamic association with the SPB. Artificially induced constitutive localization of Pcp1 on the SPB is sufficient to cause blockage of SPB fusion and formation of extra spores in diploids. Thus, Pcp1-dependent SPB quantity control is crucial for sexual reproduction and ploidy homeostasis in fission yeast.

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