Mutations in the alpha-tubulin 67C gene specifically impair achiasmate segregation in Drosophila melanogaster.
Drosophila melanogaster oocytes heterozygous for mutations in the alpha-tubulin 67C gene (alphatub67C) display defects in centromere positioning during prometaphase of meiosis I. The centromeres do not migrate to the poleward edges of the chromatin mass, and the chromatin fails to stretch during spindle lengthening. These results suggest that the poleward forces acting at the kinetochore are compromised in the alphatub67C mutants. Genetic studies demonstrate that these mutations also strongly and specifically decrease the fidelity of achiasmate chromosome segregation. Proper centromere orientation, chromatin elongation, and faithful segregation can all be restored by a decrease in the amount of the Nod chromokinesin. These results suggest that the accurate segregation of achiasmate chromosomes requires the proper balancing of forces acting on the chromosomes during prometaphase.
Matthies
H J
HJ
Department of Genetics, Section of Molecular and Cellular Biology, University of California at Davis, Davis, California 95616, USA.
Messina
L G
LG
Namba
R
R
Greer
K J
KJ
Walker
M Y
MY
Hawley
R S
RS
D000818:Animals; D002503:Centromere / Q000235:genetics / Q000378:metabolism; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D020090:Chromosome Segregation / Q000235:genetics*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D005260:Female; D018628:Gene Dosage; D005799:Genes, Dominant / Q000235:genetics / Q000502:physiology; D017344:Genes, Insect / Q000235:genetics*; D016547:Kinesins; D008540:Meiosis / Q000235:genetics; D008868:Microtubule Proteins / Q000235:genetics / Q000378:metabolism; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics*; D009630:Nondisjunction, Genetic; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D008941:Spindle Apparatus / Q000235:genetics / Q000502:physiology; D014404:Tubulin / Q000235:genetics* / Q000378:metabolism*; D014960:X Chromosome / Q000235:genetics / Q000378:metabolism
D002843:Chromatin; D029721:Drosophila Proteins; D008868:Microtubule Proteins; D014404:Tubulin; C080298:Nod protein, Drosophila; D016547:Kinesins