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mini spindles: A gene encoding a conserved microtubule-associated protein required for the integrity of the mitotic spindle in Drosophila.

Cullen CF, Deák P, Glover DM, Ohkura H - J. Cell Biol. (1999)

Bottom Line: Mutation in msps disrupts the structural integrity of the mitotic spindle, resulting in the formation of one or more small additional spindles in diploid cells.The msps gene encodes a 227-kD protein with high similarity to the vertebrate microtubule-associated proteins (MAPs), human TOGp and Xenopus XMAP215, and with limited similarity to the Dis1 and STU2 proteins from fission yeast and budding yeast.In the embryonic division cycles, Msps protein localizes to centrosomal regions at all mitotic stages, and spreads over the spindles during metaphase and anaphase.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cell and Molecular Biology, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom.

ABSTRACT
We describe a new Drosophila gene, mini spindles (msps) identified in a cytological screen for mitotic mutant. Mutation in msps disrupts the structural integrity of the mitotic spindle, resulting in the formation of one or more small additional spindles in diploid cells. Nucleation of microtubules from centrosomes, metaphase alignment of chromosomes, or the focusing of spindle poles appears much less affected. The msps gene encodes a 227-kD protein with high similarity to the vertebrate microtubule-associated proteins (MAPs), human TOGp and Xenopus XMAP215, and with limited similarity to the Dis1 and STU2 proteins from fission yeast and budding yeast. Consistent with their sequence similarity, Msps protein also associates with microtubules in vitro. In the embryonic division cycles, Msps protein localizes to centrosomal regions at all mitotic stages, and spreads over the spindles during metaphase and anaphase. The absence of centrosomal staining in interphase of the cellularized embryos suggests that the interactions between Msps protein and microtubules or centrosomes may be regulated during the cell cycle.

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Msps protein localizes to mitotic spindles and the centrosomal regions. Wild-type syncytial embryos were immunostained with α-tubulin and Msps antibodies and stained with DAPI to reveal DNA. In merged images, DNA, tubulin, and Msps staining are represented as blue, green, and red, respectively. Bar, 10 μm.
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Figure 7: Msps protein localizes to mitotic spindles and the centrosomal regions. Wild-type syncytial embryos were immunostained with α-tubulin and Msps antibodies and stained with DAPI to reveal DNA. In merged images, DNA, tubulin, and Msps staining are represented as blue, green, and red, respectively. Bar, 10 μm.

Mentions: We first examined mitotic cycles 11–13 which take place at the cortex of syncytial embryos (Fig. 7). In prophase, when chromosomes start condensing, we observed microtubules radiating from two discrete regions around the nucleus. That these discrete regions correspond to centrosomes was confirmed using an antibody against a centrosomal antigen, CP190 (data not shown). Affinity-purified antibody against Msps protein revealed that Msps protein localizes predominantly around the centrosomes at this stage.


mini spindles: A gene encoding a conserved microtubule-associated protein required for the integrity of the mitotic spindle in Drosophila.

Cullen CF, Deák P, Glover DM, Ohkura H - J. Cell Biol. (1999)

Msps protein localizes to mitotic spindles and the centrosomal regions. Wild-type syncytial embryos were immunostained with α-tubulin and Msps antibodies and stained with DAPI to reveal DNA. In merged images, DNA, tubulin, and Msps staining are represented as blue, green, and red, respectively. Bar, 10 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169485&req=5

Figure 7: Msps protein localizes to mitotic spindles and the centrosomal regions. Wild-type syncytial embryos were immunostained with α-tubulin and Msps antibodies and stained with DAPI to reveal DNA. In merged images, DNA, tubulin, and Msps staining are represented as blue, green, and red, respectively. Bar, 10 μm.
Mentions: We first examined mitotic cycles 11–13 which take place at the cortex of syncytial embryos (Fig. 7). In prophase, when chromosomes start condensing, we observed microtubules radiating from two discrete regions around the nucleus. That these discrete regions correspond to centrosomes was confirmed using an antibody against a centrosomal antigen, CP190 (data not shown). Affinity-purified antibody against Msps protein revealed that Msps protein localizes predominantly around the centrosomes at this stage.

Bottom Line: Mutation in msps disrupts the structural integrity of the mitotic spindle, resulting in the formation of one or more small additional spindles in diploid cells.The msps gene encodes a 227-kD protein with high similarity to the vertebrate microtubule-associated proteins (MAPs), human TOGp and Xenopus XMAP215, and with limited similarity to the Dis1 and STU2 proteins from fission yeast and budding yeast.In the embryonic division cycles, Msps protein localizes to centrosomal regions at all mitotic stages, and spreads over the spindles during metaphase and anaphase.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cell and Molecular Biology, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom.

ABSTRACT
We describe a new Drosophila gene, mini spindles (msps) identified in a cytological screen for mitotic mutant. Mutation in msps disrupts the structural integrity of the mitotic spindle, resulting in the formation of one or more small additional spindles in diploid cells. Nucleation of microtubules from centrosomes, metaphase alignment of chromosomes, or the focusing of spindle poles appears much less affected. The msps gene encodes a 227-kD protein with high similarity to the vertebrate microtubule-associated proteins (MAPs), human TOGp and Xenopus XMAP215, and with limited similarity to the Dis1 and STU2 proteins from fission yeast and budding yeast. Consistent with their sequence similarity, Msps protein also associates with microtubules in vitro. In the embryonic division cycles, Msps protein localizes to centrosomal regions at all mitotic stages, and spreads over the spindles during metaphase and anaphase. The absence of centrosomal staining in interphase of the cellularized embryos suggests that the interactions between Msps protein and microtubules or centrosomes may be regulated during the cell cycle.

Show MeSH
Related in: MedlinePlus