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Spindle assembly and cytokinesis in the absence of chromosomes during Drosophila male meiosis.

Bucciarelli E, Giansanti MG, Bonaccorsi S, Gatti M - J. Cell Biol. (2003)

Bottom Line: The cells containing chromosome-free spindles are also able to assemble regular cytokinetic structures and cleave normally.In addition, chromosome-free spindles normally accumulate the Aurora B kinase at their midzones.This suggests that the association of Aurora B with chromosomes is not a prerequisite for its accumulation at the central spindle, or for its function during cytokinesis.

View Article: PubMed Central - PubMed

Affiliation: Istituto Pasteur Fondazione Cenci Bolognetti, 00185 Rome, Italy.

ABSTRACT
A large body of work indicates that chromosomes play a key role in the assembly of both a centrosomal and centrosome-containing spindles. In animal systems, the absence of chromosomes either prevents spindle formation or allows the assembly of a metaphase-like spindle that fails to evolve into an ana-telophase spindle. Here, we show that Drosophila secondary spermatocytes can assemble morphologically normal spindles in the absence of chromosomes. The Drosophila mutants fusolo and solofuso are severely defective in chromosome segregation and produce secondary spermatocytes that are devoid of chromosomes. The centrosomes of these anucleated cells form robust asters that give rise to bipolar spindles that undergo the same ana-telophase morphological transformations that characterize normal spindles. The cells containing chromosome-free spindles are also able to assemble regular cytokinetic structures and cleave normally. In addition, chromosome-free spindles normally accumulate the Aurora B kinase at their midzones. This suggests that the association of Aurora B with chromosomes is not a prerequisite for its accumulation at the central spindle, or for its function during cytokinesis.

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Pav accumulates at the central spindle midzone of chromosome-free telophases. Cells were stained for tubulin (green), Pav (orange), and DNA (blue). (a) Telophase II from wild-type males. (b) Chromosome-free telophase II from fsl mutants. Bar, 10 μm.
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fig3: Pav accumulates at the central spindle midzone of chromosome-free telophases. Cells were stained for tubulin (green), Pav (orange), and DNA (blue). (a) Telophase II from wild-type males. (b) Chromosome-free telophase II from fsl mutants. Bar, 10 μm.

Mentions: In contrast to Drosophila spermatocytes, chromosome-free metaphase-like spindles of PtK homokaryons are unable to evolve into a typical telophase structure. In these peculiar spindles, the antiparallel MTs emanating from the centrosomes give rise to a compact MT bundle that fails to bind the MKLP (CHO1) kinesin, which accumulates at the central spindle midzone in chromosome-containing cells (Faruki et al., 2002). Thus, we asked whether the central spindles of chromosome-free telophases have the ability to bind Pavarotti (Pav), the Drosophila orthologue of MKLP (Adams et al., 1998). This analysis revealed that these telophases normally accumulate Pav in their midzones (Fig. 3), indicating a correct organization of central spindle MTs.


Spindle assembly and cytokinesis in the absence of chromosomes during Drosophila male meiosis.

Bucciarelli E, Giansanti MG, Bonaccorsi S, Gatti M - J. Cell Biol. (2003)

Pav accumulates at the central spindle midzone of chromosome-free telophases. Cells were stained for tubulin (green), Pav (orange), and DNA (blue). (a) Telophase II from wild-type males. (b) Chromosome-free telophase II from fsl mutants. Bar, 10 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2172764&req=5

fig3: Pav accumulates at the central spindle midzone of chromosome-free telophases. Cells were stained for tubulin (green), Pav (orange), and DNA (blue). (a) Telophase II from wild-type males. (b) Chromosome-free telophase II from fsl mutants. Bar, 10 μm.
Mentions: In contrast to Drosophila spermatocytes, chromosome-free metaphase-like spindles of PtK homokaryons are unable to evolve into a typical telophase structure. In these peculiar spindles, the antiparallel MTs emanating from the centrosomes give rise to a compact MT bundle that fails to bind the MKLP (CHO1) kinesin, which accumulates at the central spindle midzone in chromosome-containing cells (Faruki et al., 2002). Thus, we asked whether the central spindles of chromosome-free telophases have the ability to bind Pavarotti (Pav), the Drosophila orthologue of MKLP (Adams et al., 1998). This analysis revealed that these telophases normally accumulate Pav in their midzones (Fig. 3), indicating a correct organization of central spindle MTs.

Bottom Line: The cells containing chromosome-free spindles are also able to assemble regular cytokinetic structures and cleave normally.In addition, chromosome-free spindles normally accumulate the Aurora B kinase at their midzones.This suggests that the association of Aurora B with chromosomes is not a prerequisite for its accumulation at the central spindle, or for its function during cytokinesis.

View Article: PubMed Central - PubMed

Affiliation: Istituto Pasteur Fondazione Cenci Bolognetti, 00185 Rome, Italy.

ABSTRACT
A large body of work indicates that chromosomes play a key role in the assembly of both a centrosomal and centrosome-containing spindles. In animal systems, the absence of chromosomes either prevents spindle formation or allows the assembly of a metaphase-like spindle that fails to evolve into an ana-telophase spindle. Here, we show that Drosophila secondary spermatocytes can assemble morphologically normal spindles in the absence of chromosomes. The Drosophila mutants fusolo and solofuso are severely defective in chromosome segregation and produce secondary spermatocytes that are devoid of chromosomes. The centrosomes of these anucleated cells form robust asters that give rise to bipolar spindles that undergo the same ana-telophase morphological transformations that characterize normal spindles. The cells containing chromosome-free spindles are also able to assemble regular cytokinetic structures and cleave normally. In addition, chromosome-free spindles normally accumulate the Aurora B kinase at their midzones. This suggests that the association of Aurora B with chromosomes is not a prerequisite for its accumulation at the central spindle, or for its function during cytokinesis.

Show MeSH
Related in: MedlinePlus