Mars, a Drosophila protein related to vertebrate HURP, is required for the attachment of centrosomes to the mitotic spindle during syncytial nuclear divisions.
The formation of the mitotic spindle is controlled by the microtubule organizing activity of the centrosomes and by the effects of chromatin-associated Ran-GTP on the activities of spindle assembly factors. In this study we show that Mars, a Drosophila protein with sequence similarity to vertebrate hepatoma upregulated protein (HURP), is required for the attachment of the centrosome to the mitotic spindle. More than 80% of embryos derived from mars mutant females do not develop properly due to severe mitotic defects during the rapid nuclear divisions in early embryogenesis. Centrosomes frequently detach from spindles and from the nuclear envelope and nucleate astral microtubules in ectopic positions. Consistent with its function in spindle organization, Mars localizes to nuclei in interphase and associates with the mitotic spindle, in particular with the spindle poles, during mitosis. We propose that Mars is an important linker between the spindle and the centrosomes that is required for proper spindle organization during the rapid mitotic cycles in early embryogenesis.
Zhang
Gang
G
Abteilung Stammzellbiologie, DFG Research Center for Molecular Physiology of the Brain (CMPB), Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
Breuer
Manuel
M
Förster
Ankathrin
A
Egger-Adam
Diane
D
Wodarz
Andreas
A
D000818:Animals; D064127:Aurora Kinases; D001756:Blastoderm / Q000166:cytology / Q000378:metabolism; D018797:Cell Cycle Proteins; D002460:Cell Line; D048750:Cell Nucleus Division; D018385:Centrosome / Q000378:metabolism* / Q000648:ultrastructure; D003703:Demecolcine / Q000494:pharmacology; D029721:Drosophila Proteins / Q000172:deficiency; D004331:Drosophila melanogaster; D004398:Dyneins / Q000172:deficiency; D005260:Female; D008297:Male; D018613:Microscopy, Confocal; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D016296:Mutagenesis; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency; D017434:Protein Structure, Tertiary / Q000502:physiology; D000074407:SAP90-PSD95 Associated Proteins; D008941:Spindle Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D050257:Tubulin Modulators / Q000494:pharmacology
D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; C532763:HURP protein, mouse; C000614192:Mars protein, Drosophila; D009419:Nerve Tissue Proteins; D000074407:SAP90-PSD95 Associated Proteins; D050257:Tubulin Modulators; C072004:polo protein, Drosophila; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D004398:Dyneins; D003703:Demecolcine