Chromosome Segregation in C. Elegans Female Meiosis is Accompanied by a Switch in Lateral to End-On Microtubule Orientation

2018 ◽  
Author(s):  
Stefanie Redemann ◽  
Ina Lantzsch ◽  
Norbert Lindow ◽  
Steffen Prohaska ◽  
Martin Srayko ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Female Meiosis ◽  
Microtubule Orientation ◽  
C Elegans

scholarly journals Katanin controls mitotic and meiotic spindle length

2006 ◽  
Vol 175 (6) ◽  
pp. 881-891 ◽  
Author(s):  
Karen McNally ◽  
Anjon Audhya ◽  
Karen Oegema ◽  
Francis J. McNally
Keyword(s):  
Chromosome Segregation ◽  
Eukaryotic Cell ◽  
Meiotic Spindle ◽  
Mitotic Spindles ◽  
Wild Type ◽  
Female Meiosis ◽  
C Elegans ◽  
Microtubule Severing ◽  
Spindle Poles ◽  
Type C

Accurate control of spindle length is a conserved feature of eukaryotic cell division. Lengthening of mitotic spindles contributes to chromosome segregation and cytokinesis during mitosis in animals and fungi. In contrast, spindle shortening may contribute to conservation of egg cytoplasm during female meiosis. Katanin is a microtubule-severing enzyme that is concentrated at mitotic and meiotic spindle poles in animals. We show that inhibition of katanin slows the rate of spindle shortening in nocodazole-treated mammalian fibroblasts and in untreated Caenorhabditis elegans meiotic embryos. Wild-type C. elegans meiotic spindle shortening proceeds through an early katanin-independent phase marked by increasing microtubule density and a second, katanin-dependent phase that occurs after microtubule density stops increasing. In addition, double-mutant analysis indicated that γ-tubulin–dependent nucleation and microtubule severing may provide redundant mechanisms for increasing microtubule number during the early stages of meiotic spindle assembly.

scholarly journals Chromosome segregation during female meiosis in C. elegans: A tale of pushing and pulling

2020 ◽  
Vol 219 (12) ◽  
Author(s):  
Samuel J.P. Taylor ◽  
Federico Pelisch
Keyword(s):  
Chromosome Segregation ◽  
Meiotic Chromosome ◽  
Female Meiosis ◽  
C Elegans ◽  
Early Stages ◽  
Pushing And Pulling

The role of the kinetochore during meiotic chromosome segregation in C. elegans oocytes has been a matter of controversy. Danlasky et al. (2020. J. Cell. Biol.https://doi.org/10.1083/jcb.202005179) show that kinetochore proteins KNL-1 and KNL-3 are required for early stages of anaphase during female meiosis, suggesting a new kinetochore-based model of chromosome segregation.

scholarly journals Human female meiosis revised: new insights into the mechanisms of chromosome segregation and aneuploidies from advanced genomics and time-lapse imaging

2017 ◽  
Vol 23 (6) ◽  
pp. 706-722 ◽  
Author(s):  
Antonio Capalbo ◽  
Eva R Hoffmann ◽  
Danilo Cimadomo ◽  
Filippo Maria Ubaldi ◽  
Laura Rienzi
Keyword(s):  
Chromosome Segregation ◽  
Time Lapse ◽  
Human Female ◽  
Female Meiosis ◽  
Time Lapse Imaging ◽  
Human Female Meiosis

scholarly journals BUB-1 targets PP2A:B56 to regulate chromosome congression during meiosis I in C. elegans oocytes

2020 ◽  
Author(s):  
Laura Bel Borja ◽  
Flavie Soubigou ◽  
Samuel J.P. Taylor ◽  
Conchita Fraguas Bringas ◽  
Jacqueline Budrewicz ◽  
...  
Keyword(s):  
Kinase Domain ◽  
Meiotic Spindle ◽  
Dependent Manner ◽  
Female Meiosis ◽  
Linear Motif ◽  
Interaction Domain ◽  
C Elegans ◽  
Chromosome Congression ◽  
B Subunits ◽  
Meiosis I

ABSTRACTProtein Phosphatase 2A (PP2A) is an heterotrimer composed of scaffolding (A), catalytic (C), and regulatory (B) subunits with various key roles during cell division. While A and C subunits form the core enzyme, the diversity generated by interchangeable B subunits dictates substrate specificity. Within the B subunits, B56-type subunits play important roles during meiosis in yeast and mice by protecting centromeric cohesion and stabilising the kinetochore-microtubule attachments. These functions are achieved through targeting of B56 subunits to centromere and kinetochore by Shugoshin and BUBR1. In the nematode Caenorhabditis elegans (C. elegans) the closest BUBR1 ortholog lacks the B56 interaction domain and the Shugoshin orthologue is not required for normal segregation during oocyte meiosis. Therefore, the role of PP2A in C. elegans female meiosis is not known. Here, we report that PP2A is essential for meiotic spindle assembly and chromosome dynamics during C. elegans female meiosis. Specifically, B56 subunits PPTR-1 and PPTR-2 associate with chromosomes during prometaphase I and regulate chromosome congression. The chromosome localization of B56 subunits does not require shugoshin orthologue SGO-1. Instead we have identified the kinase BUB-1 as the key B56 targeting factor to the chromosomes during meiosis. PP2A BUB-1 recruits PP2A:B56 to the chromosomes via dual mechanism: 1) PPTR-1/2 interacts with the newly identified LxxIxE short linear motif (SLiM) within a disordered region in BUB-1 in a phosphorylation-dependent manner; and 2) PPTR-2 can also be recruited to chromosomes in a BUB-1 kinase domain-dependent manner. Our results highlight a novel, BUB-1-dependent mechanism for B56 recruitment, essential for recruiting a pool of PP2A required for proper chromosome congression during meiosis I.

scholarly journals Mixing and Matching Chromosomes during Female Meiosis

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 696
Author(s):  
Thomas Rubin ◽  
Nicolas Macaisne ◽  
Jean-René Huynh
Keyword(s):  
Female Meiosis ◽  
Homologous Chromosomes ◽  
C Elegans ◽  
Similarities And Differences ◽  
Segregation Of Chromosomes

Meiosis is a key event in the manufacturing of an oocyte. During this process, the oocyte creates a set of unique chromosomes by recombining paternal and maternal copies of homologous chromosomes, and by eliminating one set of chromosomes to become haploid. While meiosis is conserved among sexually reproducing eukaryotes, there is a bewildering diversity of strategies among species, and sometimes within sexes of the same species, to achieve proper segregation of chromosomes. Here, we review the very first steps of meiosis in females, when the maternal and paternal copies of each homologous chromosomes have to move, find each other and pair. We explore the similarities and differences observed in C. elegans, Drosophila, zebrafish and mouse females.

Evidence that the spindle assembly checkpoint does not regulate APCFzy activity in Drosophila female meiosis

Genome ◽  
2012 ◽  
Vol 55 (1) ◽  
pp. 63-67 ◽  
Author(s):  
Osamah Batiha ◽  
Andrew Swan
Keyword(s):  
Chromosome Segregation ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Cyclin B ◽  
Meiotic Spindle ◽  
Loss Of Function ◽  
Female Meiosis ◽  
Chromosome Attachment ◽  
Spindle Microtubules ◽  
Made In

The spindle assembly checkpoint (SAC) plays an important role in mitotic cells to sense improper chromosome attachment to spindle microtubules and to inhibit APCFzy-dependent destruction of cyclin B and Securin; consequent initiation of anaphase until correct attachments are made. In Drosophila , SAC genes have been found to play a role in ensuring proper chromosome segregation in meiosis, possibly reflecting a similar role for the SAC in APCFzy inhibition during meiosis. We found that loss of function mutations in SAC genes, Mad2, zwilch, and mps1, do not lead to the predicted rise in APCFzy-dependent degradation of cyclin B either globally throughout the egg or locally on the meiotic spindle. Further, the SAC is not responsible for the inability of APCFzy to target cyclin B and promote anaphase in metaphase II arrested eggs from cort mutant females. Our findings support the argument that SAC proteins play checkpoint independent roles in Drosophila female meiosis and that other mechanisms must function to control APC activity.

scholarly journals The Caenorhabditis elegans Homologue of Deleted in Azoospermia Is Involved in the Sperm/Oocyte Switch

2006 ◽  
Vol 17 (7) ◽  
pp. 3147-3155 ◽  
Author(s):  
Muneyoshi Otori ◽  
Takeshi Karashima ◽  
Masayuki Yamamoto
Keyword(s):  
Caenorhabditis Elegans ◽  
Caenorhabditis Briggsae ◽  
Essential Factor ◽  
Female Meiosis ◽  
Stem Cell Proliferation ◽  
C Elegans ◽  
Essential Step ◽  
Deleted In Azoospermia ◽  
Translational Regulators ◽  
Daz Gene

The Deleted in Azoospermia (DAZ) gene family encodes putative translational activators that are required for meiosis and other aspects of gametogenesis in animals. The single Caenorhabditis elegans homologue of DAZ, daz-1, is an essential factor for female meiosis. Here, we show that daz-1 is important for the switch from spermatogenesis to oogenesis (the sperm/oocyte switch), which is an essential step for the hermaphrodite germline to produce oocytes. RNA interference of the daz-1 orthologue in a related nematode, Caenorhabditis briggsae, resulted in a complete loss of the sperm/oocyte switch. The C. elegans hermaphrodite deficient in daz-1 also revealed a failure in the sperm/oocyte switch if the genetic background was conditional masculinization of germline. DAZ-1 could bind specifically to mRNAs encoding the FBF proteins, which are translational regulators for the sperm/oocyte switch and germ stem cell proliferation. Expression of the FBF proteins seemed to be lowered in the daz-1 mutant at the stage for the sperm/oocyte switch. Conversely, a mutation in gld-3, a gene that functionally counteracts FBF, could partially restore oogenesis in the daz-1 mutant. Together, we propose that daz-1 plays a role upstream of the pathway for germ cell sex determination.

scholarly journals Mitotic chromosome condensation requires phosphorylation of the centromeric protein KNL-2 in C. elegans

2021 ◽  
Author(s):  
Joanna M Wenda ◽  
Reinier F Prosée ◽  
Caroline Gabus ◽  
Florian A Steiner
Keyword(s):  
Chromosome Segregation ◽  
Mitotic Chromosome ◽  
Chromosome Condensation ◽  
Embryonic Lethality ◽  
Phosphorylation Sites ◽  
C Elegans ◽  
Microtubule Attachment ◽  
Centromeric Protein ◽  
Mitotic Chromosome Condensation

Centromeres are chromosomal regions that serve as sites for kinetochore formation and microtubule attachment, processes that are essential for chromosome segregation during mitosis. Centromeres are almost universally defined by the histone variant CENP-A. In the holocentric nematode C. elegans, CENP-A deposition depends on the loading factor KNL-2. Depletion of either CENP-A or KNL-2 results in defects in centromere maintenance, chromosome condensation and kinetochore formation, leading to chromosome segregation failure. Here, we show that KNL-2 is phosphorylated by CDK-1, and that mutation of three C-terminal phosphorylation sites causes chromosome segregation defects and an increase in embryonic lethality. In strains expressing phosphodeficient KNL-2, CENP-A and kinetochore proteins are properly localised, indicating that the role of KNL-2 in centromere maintenance is not affected. Instead, the mutant embryos exhibit reduced mitotic levels of condensin II on chromosomes and significant chromosome condensation impairment. Our findings separate the functions of KNL-2 in CENP-A loading and chromosome condensation and demonstrate that KNL-2 phosphorylation regulates the cooperation between centromeric regions and the condensation machinery in C. elegans.

scholarly journals Male meiotic spindle features that efficiently segregate paired and lagging chromosomes

2019 ◽  
Author(s):  
Gunar Fabig ◽  
Robert Kiewisz ◽  
Norbert Lindow ◽  
James A. Powers ◽  
Vanessa Cota ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Chromosome Pairing ◽  
Electron Tomography ◽  
Male Meiosis ◽  
Meiotic Spindle ◽  
Sperm Production ◽  
C Elegans ◽  
Anaphase Onset ◽  
Unpaired Chromosome ◽  
Anaphase B

AbstractChromosome segregation during male meiosis is tailored to rapidly generate multitudes of sperm. Little, however, is known about the mechanisms that efficiently segregate chromosomes to produce sperm. Using live imaging in Caenorhabditis elegans, we find that spermatocytes exhibit simultaneous pole-to-chromosome shortening (anaphase A) and pole-to-pole elongation (anaphase B). Electron tomography unexpectedly revealed that spermatocyte anaphase A does not stem from kinetochore microtubule shortening. Instead, movement is driven by changes in distance between chromosomes, microtubules, and centrosomes upon tension release at anaphase onset. We also find that the lagging X chromosome, a distinctive feature of anaphase I in C. elegans males, is due to lack of chromosome pairing. The unpaired chromosome remains tethered to centrosomes by continuously lengthening kinetochore microtubules which are under tension, suggesting a ‘tug of war’ that can reliably resolve chromosome lagging. Overall, we define features that partition both paired and lagging chromosomes for optimal sperm production.

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