scholarly journals 14-3-3 regulation of Ncd reveals a new mechanism for targeting proteins to the spindle in oocytes

2017 ◽  
Vol 216 (10) ◽  
pp. 3029-3039 ◽  
Author(s):  
Robin Beaven ◽  
Ricardo Nunes Bastos ◽  
Christos Spanos ◽  
Pierre Romé ◽  
C. Fiona Cullen ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Large Volume ◽  
Inhibitory Effect ◽  
Binding Activity ◽  
Meiotic Spindle ◽  
Aurora B ◽  
Bipolar Spindle ◽  
Local Activation ◽  
Spindle Microtubules ◽  
Specific Association

The meiotic spindle is formed without centrosomes in a large volume of oocytes. Local activation of crucial spindle proteins around chromosomes is important for formation and maintenance of a bipolar spindle in oocytes. We found that phosphodocking 14-3-3 proteins stabilize spindle bipolarity in Drosophila melanogaster oocytes. A critical 14-3-3 target is the minus end–directed motor Ncd (human HSET; kinesin-14), which has well-documented roles in stabilizing a bipolar spindle in oocytes. Phospho docking by 14-3-3 inhibits the microtubule binding activity of the nonmotor Ncd tail. Further phosphorylation by Aurora B kinase can release Ncd from this inhibitory effect of 14-3-3. As Aurora B localizes to chromosomes and spindles, 14-3-3 facilitates specific association of Ncd with spindle microtubules by preventing Ncd from binding to nonspindle microtubules in oocytes. Therefore, 14-3-3 translates a spatial cue provided by Aurora B to target Ncd selectively to the spindle within the large volume of oocytes.

scholarly journals The molecular architecture of the meiotic spindle is remodeled during metaphase arrest in oocytes

2019 ◽  
Vol 218 (9) ◽  
pp. 2854-2864 ◽  
Author(s):  
Mariana F.A. Costa ◽  
Hiroyuki Ohkura
Keyword(s):  
Drosophila Melanogaster ◽  
Meiotic Spindle ◽  
Cross Linking ◽  
Molecular Architecture ◽  
Metaphase Arrest ◽  
Bipolar Spindle ◽  
Microtubule Attachment ◽  
Insight Into ◽  
Transgenic Flies ◽  
Metaphase I

Before fertilization, oocytes of most species undergo a long, natural arrest in metaphase. Before this, prometaphase I is also prolonged, due to late stable kinetochore–microtubule attachment. How oocytes stably maintain the dynamic spindle for hours during these periods is poorly understood. Here we report that the bipolar spindle changes its molecular architecture during the long prometaphase/metaphase I in Drosophila melanogaster oocytes. By generating transgenic flies expressing GFP-tagged spindle proteins, we found that 14 of 25 spindle proteins change their distribution in the bipolar spindle. Among them, microtubule cross-linking kinesins, MKlp1/Pavarotti and kinesin-5/Klp61F, accumulate to the spindle equator in late metaphase. We found that the late equator accumulation of MKlp1/Pavarotti is regulated by a mechanism distinct from that in mitosis. While MKlp1/Pavarotti contributes to the control of spindle length, kinesin-5/Klp61F is crucial for maintaining a bipolar spindle during metaphase I arrest. Our study provides novel insight into how oocytes maintain a bipolar spindle during metaphase arrest.

scholarly journals Mutations in orbit/mast reveal that the central spindle is comprised of two microtubule populations, those that initiate cleavage and those that propagate furrow ingression

2004 ◽  
Vol 166 (1) ◽  
pp. 49-60 ◽  
Author(s):  
Yoshihiro H. Inoue ◽  
Matthew S. Savoian ◽  
Takao Suzuki ◽  
Endre Máthé ◽  
Masa-Toshi Yamamoto ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Time Lapse ◽  
Aurora B ◽  
Cleavage Furrow ◽  
Imaging Studies ◽  
Aurora B Kinase ◽  
Central Spindle ◽  
Spindle Microtubules ◽  
Time Lapse Imaging ◽  
Actin Rings

We address the relative roles of astral and central spindle microtubules (MTs) in cytokinesis of Drosophila melanogaster primary spermatocytes. Time-lapse imaging studies reveal that the central spindle is comprised of two MT populations, “interior” central spindle MTs found within the spindle envelope and “peripheral” astral MTs that probe the cytoplasm and initiate cleavage furrows where they contact the cortex and form overlapping bundles. The MT-associated protein Orbit/Mast/CLASP concentrates on interior rather than peripheral central spindle MTs. Interior MTs are preferentially affected in hypomorphic orbit mutants, and consequently the interior central spindle fails to form or is unstable. In contrast, peripheral MTs still probe the cortex and form regions of overlap that recruit the Pav-KLP motor and Aurora B kinase. orbit mutants have disorganized or incomplete anillin and actin rings, and although cleavage furrows initiate, they ultimately regress. Our work identifies a new function for Orbit/Mast/CLASP and identifies a novel MT population involved in cleavage furrow initiation.

scholarly journals Borealin directs recruitment of the CPC to oocyte chromosomes and movement to the microtubules

2021 ◽  
Vol 220 (6) ◽  
Author(s):  
Lin-Ing Wang ◽  
Tyler DeFosse ◽  
Janet K. Jang ◽  
Rachel A. Battaglia ◽  
Victoria F. Wagner ◽  
...  
Keyword(s):  
Homologous Chromosome ◽  
Spindle Assembly ◽  
Aurora B ◽  
Aurora B Kinase ◽  
Central Spindle ◽  
Bipolar Spindle ◽  
Spindle Microtubules ◽  
Chromosome Passenger Complex

The chromosomes in the oocytes of many animals appear to promote bipolar spindle assembly. In Drosophila oocytes, spindle assembly requires the chromosome passenger complex (CPC), which consists of INCENP, Borealin, Survivin, and Aurora B. To determine what recruits the CPC to the chromosomes and its role in spindle assembly, we developed a strategy to manipulate the function and localization of INCENP, which is critical for recruiting the Aurora B kinase. We found that an interaction between Borealin and the chromatin is crucial for the recruitment of the CPC to the chromosomes and is sufficient to build kinetochores and recruit spindle microtubules. HP1 colocalizes with the CPC on the chromosomes and together they move to the spindle microtubules. We propose that the Borealin interaction with HP1 promotes the movement of the CPC from the chromosomes to the microtubules. In addition, within the central spindle, rather than at the centromeres, the CPC and HP1 are required for homologous chromosome bi-orientation.

subito Encodes a Kinesin-like Protein Required for Meiotic Spindle Pole Formation in Drosophila melanogaster

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1489-1501 ◽  
Author(s):  
Kelly L Giunta ◽  
Janet K Jang ◽  
Elizabeth A Manheim ◽  
Gayathri Subramanian ◽  
Kim S McKim
Keyword(s):  
Drosophila Melanogaster ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Microtubule Organizing Center ◽  
Bipolar Spindle ◽  
Microtubule Associated Proteins ◽  
Organizing Center ◽  
Associated Proteins ◽  
Similar Phenotype ◽  
Meiosis I

Abstract The female meiotic spindle lacks a centrosome or microtubule-organizing center in many organisms. During cell division, these spindles are organized by the chromosomes and microtubule-associated proteins. Previous studies in Drosophila melanogaster implicated at least one kinesin motor protein, NCD, in tapering the microtubules into a bipolar spindle. We have identified a second Drosophila kinesin-like protein, SUB, that is required for meiotic spindle function. At meiosis I in males and females, sub mutations affect only the segregation of homologous chromosomes. In female meiosis, sub mutations have a similar phenotype to ncd; even though chromosomes are joined by chiasmata they fail to segregate at meiosis I. Cytological analyses have revealed that sub is required for bipolar spindle formation. In sub mutations, we observed spindles that were unipolar, multipolar, or frayed with no defined poles. On the basis of these phenotypes and the observation that sub mutations genetically interact with ncd, we propose that SUB is one member of a group of microtubule-associated proteins required for bipolar spindle assembly in the absence of the centrosomes. sub is also required for the early embryonic divisions but is otherwise dispensable for most mitotic divisions.

scholarly journals Chromosome-directed oocyte spindle assembly depends HP1 and the Chromosomal Passenger Complex

2020 ◽  
Author(s):  
Lin-Ing Wang ◽  
Tyler DeFosse ◽  
Rachel A. Battaglia ◽  
Victoria F. Wagner ◽  
Kim S. McKim
Keyword(s):  
Homologous Chromosome ◽  
Spindle Assembly ◽  
Aurora B ◽  
Aurora B Kinase ◽  
Chromosomal Passenger Complex ◽  
Central Spindle ◽  
Bipolar Spindle ◽  
Chromosomal Passenger ◽  
Spindle Microtubules

AbstractThe chromosomes in the oocytes of many animals appear to promote bipolar spindle assembly. In Drosophila oocytes, spindle assembly requires the chromosomal passenger complex (CPC), which consists of INCENP, Borealin, Survivin and Aurora B. To determine what recruits the CPC to the chromosomes and its role in spindle assembly, we developed a strategy to manipulate the function and localization of INCENP, which is critical for recruiting the Aurora B kinase. We found that an interaction between Borealin and HP1 is crucial for the initial recruitment of the CPC to the chromosomes and is sufficient to build kinetochores and recruit spindle microtubules. We also found that HP1 moves from the chromosomes to the spindle microtubules along with the CPC, and based on this, propose a mechanism for how the CPC moves from the chromosomes to the microtubules. Within the central spindle, rather than at the centromeres, the CPC and HP1 are required for homologous chromosome bi-orientation.

scholarly journals A novel microtubule nucleation pathway for meiotic spindle assembly in oocytes

2018 ◽  
Vol 217 (10) ◽  
pp. 3431-3445 ◽  
Author(s):  
Pierre Romé ◽  
Hiroyuki Ohkura
Keyword(s):  
Large Volume ◽  
Spindle Assembly ◽  
Terminal Region ◽  
Microtubule Assembly ◽  
Meiotic Spindle ◽  
Microtubule Nucleation ◽  
Unresolved Question ◽  
Nucleation Sites ◽  
Spindle Microtubules

The meiotic spindle in oocytes is assembled in the absence of centrosomes, the major microtubule nucleation sites in mitotic and male meiotic cells. A crucial, yet unresolved question in meiosis is how spindle microtubules are generated without centrosomes and only around chromosomes in the exceptionally large volume of oocytes. Here we report a novel oocyte-specific microtubule nucleation pathway that is essential for assembling most spindle microtubules complementarily with the Augmin pathway. This pathway is mediated by the kinesin-6 Subito/MKlp2, which recruits the γ-tubulin complex to the spindle equator to nucleate microtubules in Drosophila oocytes. Away from chromosomes, Subito interaction with the γ-tubulin complex is suppressed by its N-terminal region to prevent ectopic microtubule assembly in oocytes. We further demonstrate in vitro that the Subito complex from ovaries can nucleate microtubules from pure tubulin dimers. Collectively, microtubule nucleation regulated by Subito drives spatially restricted spindle assembly in oocytes.

scholarly journals The Caenorhabditis elegans Aurora B Kinase AIR-2 Phosphorylates and Is Required for the Localization of a BimC Kinesin to Meiotic and Mitotic Spindles

2005 ◽  
Vol 16 (2) ◽  
pp. 742-756 ◽  
Author(s):  
John D. Bishop ◽  
Zhenbo Han ◽  
Jill M. Schumacher
Keyword(s):  
Caenorhabditis Elegans ◽  
Meiotic Spindle ◽  
Aurora B ◽  
Tail Domain ◽  
Mitotic Spindles ◽  
Aurora B Kinase ◽  
Spindle Midzone ◽  
Spindle Microtubules ◽  
Sites Of Action

BimC kinesins are required for mitotic spindle assembly in a variety of organisms. These proteins are localized to centrosomes, spindle microtubules, and the spindle midzone. We have previously shown that the Caenorhabditis elegans Aurora B kinase AIR-2 is required for the localization of the ZEN-4 kinesin protein to midzone microtubules. To determine whether the association of BimC kinesins with spindle microtubules is also dependent on AIR-2, we examined the expression pattern of BMK-1, a C. elegans BimC kinesin, in wild-type and AIR-2–deficient embryos. BMK-1 is highly expressed in the hermaphrodite gonad and is localized to meiotic spindle microtubules in the newly fertilized embryo. In mitotic embryos, BMK-1 is associated with spindle microtubules from prophase through anaphase and is concentrated at the spindle midzone during anaphase and telophase. In the absence of AIR-2, BMK-1 localization to meiotic and mitotic spindles is greatly reduced. This is not a consequence of loss of ZEN-4 localization because BMK-1 is appropriately localized in ZEN-4–deficient embryos. Furthermore, AIR-2 and BMK-1 directly interact with one another and the C-terminal tail domain of BMK-1 is specifically phosphorylated by AIR-2 in vitro. Together with our previous data, these results suggest that at least one function of the Aurora B kinases is to recruit spindle-associated motor proteins to their sites of action.

scholarly journals A novel microtubule nucleation pathway for meiotic spindle assembly in oocytes

2018 ◽  
Author(s):  
Pierre Romé ◽  
Hiroyuki Ohkura
Keyword(s):  
Large Volume ◽  
Spindle Assembly ◽  
Terminal Region ◽  
Microtubule Assembly ◽  
Meiotic Spindle ◽  
Microtubule Nucleation ◽  
Unresolved Question ◽  
Nucleation Sites ◽  
Spindle Microtubules

AbstractThe meiotic spindle in oocytes is assembled in the absence of centrosomes, the major microtubule nucleation sites in mitotic and male meiotic cells. A crucial, yet unresolved question in meiosis is how spindle microtubules are generated without centrosomes and only around chromosomes in the large volume of oocytes. Here we report a novel oocyte-specific microtubule nucleation pathway that is essential for assembling most spindle microtubules complementarily with the Augmin pathway, and sufficient for triggering microtubule assembly in oocytes. This pathway is mediated by the kinesin-6 Subito/MKlp2, which recruits the γ-tubulin complex to the spindle equator to nucleate microtubules in Drosophila oocytes. Away from chromosomes, Subito interaction with the γ-tubulin complex is suppressed by its N-terminal region to prevent ectopic microtubule assembly in oocytes. We further demonstrate that the Subito complex from ovaries can nucleate microtubules from pure tubulin dimers in vitro. Taken together, microtubule nucleation regulated by Subito drives spatially restricted spindle assembly in oocytes.

scholarly journals Chromosome Unipolar Division and Low Expression of Tws May Cause Parthenogenesis of Rice Water Weevil (Lissorhoptrus oryzophilus Kuschel)

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 278
Author(s):  
Pengcheng Wang ◽  
Fangyuan Yang ◽  
Zhuo Ma ◽  
Runzhi Zhang
Keyword(s):  
Drosophila Melanogaster ◽  
Quantitative Pcr ◽  
Ovarian Tissue ◽  
Expression Patterns ◽  
Meiotic Spindle ◽  
Lissorhoptrus Oryzophilus ◽  
Rice Water Weevil ◽  
Rice Water ◽  
Beijing China ◽  
Low Expression

Rice water weevil (RWW) is divided into two types of population, triploid parthenogenesis and diploid bisexual reproduction. In this study, we explored the meiosis of triploid parthenogenesis RWW (Shangzhuang Town, Haidian District, Beijing, China) by marking the chromosomes and microtubules of parthenogenetic RWW oocytes via immunostaining. The immunostaining results show that there is a canonical meiotic spindle formed in the triploid parthenogenetic RWW oocytes, but chromosomes segregate at only one pole, which means that there is a chromosomal unipolar division during the oogenesis of the parthenogenetic RWW. Furthermore, we cloned the conserved sequences of parthenogenetic RWW REC8 and Tws, and designed primers based on the parthenogenetic RWW sequence to detect expression patterns by quantitative PCR (Q-PCR). Q-PCR results indicate that the expression of REC8 and Tws in ovarian tissue of bisexual Drosophila melanogaster is 0.98 and 10,000.00 times parthenogenetic RWW, respectively (p < 0.01). The results show that Tws had low expression in parthenogenetic RWW ovarian tissue, and REC8 was expressed normally. Our study suggests that the chromosomal unipolar division and deletion of Tws may cause parthenogenesis in RWW.

scholarly journals The right place at the right time: Aurora B kinase localization to centromeres and kinetochores

2020 ◽  
Vol 64 (2) ◽  
pp. 299-311 ◽  
Author(s):  
Amanda J. Broad ◽  
Jennifer G. DeLuca
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Protein Complexes ◽  
Centromeric Heterochromatin ◽  
Aurora B ◽  
Mitotic Chromosomes ◽  
Large Protein ◽  
Aurora B Kinase ◽  
Centromeric Protein ◽  
Spindle Microtubules ◽  
The Right

Abstract The fidelity of chromosome segregation during mitosis is intimately linked to the function of kinetochores, which are large protein complexes assembled at sites of centromeric heterochromatin on mitotic chromosomes. These key “orchestrators” of mitosis physically connect chromosomes to spindle microtubules and transduce forces through these connections to congress chromosomes and silence the spindle assembly checkpoint. Kinetochore-microtubule attachments are highly regulated to ensure that incorrect attachments are not prematurely stabilized, but instead released and corrected. The kinase activity of the centromeric protein Aurora B is required for kinetochore-microtubule destabilization during mitosis, but how the kinase acts on outer kinetochore substrates to selectively destabilize immature and erroneous attachments remains debated. Here, we review recent literature that sheds light on how Aurora B kinase is recruited to both centromeres and kinetochores and discuss possible mechanisms for how kinase interactions with substrates at distinct regions of mitotic chromosomes are regulated.

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