Spindle assembly and cytokinesis in the absence of chromosomes during Drosophila male meiosis.
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.
Bucciarelli
Elisabetta
E
Istituto Pasteur Fondazione Cenci Bolognetti, 00185 Rome, Italy.
Giansanti
Maria Grazia
MG
Bonaccorsi
Silvia
S
Gatti
Maurizio
M
D000818:Animals; D064127:Aurora Kinases; D002455:Cell Division / Q000502:physiology*; D018385:Centrosome / Q000502:physiology; D002875:Chromosomes / Q000502:physiology*; D004330:Drosophila / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D017344:Genes, Insect / Q000502:physiology; D008297:Male; D008540:Meiosis / Q000235:genetics / Q000502:physiology*; D008870:Microtubules / Q000378:metabolism / Q000502:physiology; D009154:Mutation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D013090:Spermatocytes / Q000166:cytology / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology*; D008941:Spindle Apparatus / Q000378:metabolism*
D029721:Drosophila Proteins; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases