Genetic dissection of meiotic cytokinesis in Drosophila males.
We have used Drosophila male meiosis as a model system for genetic dissection of the cytokinesis mechanism. Drosophila mutants defective in meiotic cytokinesis can be easily identified by their multinucleate spermatids. Moreover, the large size of meiotic spindles allows characterization of mutant phenotypes with exquisite cytological resolution. We have screened a collection of 1955 homozygous mutant male sterile lines for those with multinucleate spermatids, and thereby identified mutations in 19 genes required for cytokinesis. These include 16 novel loci and three genes, diaphanous, four wheel drive, and pebble, already known to be involved in Drosophila cytokinesis. To define the primary defects leading to failure of cytokinesis, we analyzed meiotic divisions in male mutants for each of these 19 genes. Examination of preparations stained for tubulin, anillin, KLP3A, and F-actin revealed discrete defects in the components of the cytokinetic apparatus, suggesting that these genes act at four major points in a stepwise pathway for cytokinesis. Our results also indicated that the central spindle and the contractile ring are interdependent structures that interact throughout cytokinesis. Moreover, our genetic and cytological analyses provide further evidence for a cell type-specific control of Drosophila cytokinesis, suggesting that several genes required for meiotic cytokinesis in males are not required for mitotic cytokinesis.
Istituto Pasteur Fondazione Cenci Bolognetti and Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Genetica e Biologia Molecolare, Universitá La Sapienza, 00185 Rome, Italy.
Maria Grazia
MG
Giansanti
Rebecca M
RM
Farkas
Silvia
S
Bonaccorsi
Dan L
DL
Lindsley
Barbara T
BT
Wakimoto
Margaret T
MT
Fuller
Maurizio
M
Gatti
D000205:Actomyosin / Q000032:analysis / Q000378:metabolism; D000818:Animals; D002467:Cell Nucleus / Q000235:genetics; D002874:Chromosome Mapping; D003285:Contractile Proteins / Q000032:analysis / Q000378:metabolism; D004330:Drosophila / Q000166:cytology* / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics; D017344:Genes, Insect / Q000235:genetics; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics; D016547:Kinesins / Q000032:analysis / Q000378:metabolism; D008297:Male; D008540:Meiosis / Q000235:genetics; D008938:Mitosis / Q000235:genetics; D009154:Mutation / Q000235:genetics; D013087:Spermatids / Q000166:cytology; D013090:Spermatocytes / Q000166:cytology* / Q000378:metabolism; D014404:Tubulin / Q000032:analysis / Q000378:metabolism
D003285:Contractile Proteins; D029721:Drosophila Proteins; D020662:Guanine Nucleotide Exchange Factors; C093317:Klp3A protein, Drosophila; C121865:Pbl protein, Drosophila; D014404:Tubulin; C095886:anillin; D000205:Actomyosin; D016547:Kinesins