The Ncd microtubule motor protein is required for meiotic and early mitotic chromosome distribution in Drosophila. Null mutant females expressing the Ncd motor fused to the Aequorea victoria green fluorescent protein (GFP), regulated by the wild-type ncd promoter, are rescued for chromosome segregation and embryo viability. Analysis of mitosis in live embryos shows cell cycle-dependent localization of Ncd-GFP to centrosomes and spindles. The distribution of Ncd-GFP in spindles during metaphase differs strikingly from that of tubulin: the tubulin staining is excluded by the chromosomes at the metaphase plate; in contrast, Ncd-GFP forms filaments along the spindle microtubules that extend across the chromosomes. The existence of Ncd-GFP fibers that cross the metaphase plate suggests that Ncd interacts functionally with chromosomes in metaphase. Differences are no longer observed in anaphase when the chromosomes have moved off the metaphase plate. A mutant form of Ncd fused to GFP also localizes to spindles in live embryos. Mutant embryos show frequent centrosome and spindle abnormalities, including free centrosomes that dissociate from interphase nuclei, precociously split centrosomes, and spindles with microtubule spurs or bridges to nearby spindles. The precociously split and free centrosomes indicate that the Ncd motor acts in cleavage stage embryos to maintain centrosome integrity and attachment to nuclei. The frequent spindle spurs of mutant embryos are associated with mis-segregating chromosomes that partially detach from the spindle in metaphase, but can be recaptured in early anaphase. This implies that the Ncd motor functions to prevent chromosome loss by maintaining chromosome attachment to the spindle in metaphase, consistent with the Ncd-GFP fibers that across the metaphase plate.

Axton
J. M.
,
Dombradi
V.
,
Cohen
P. T.
,
Glover
D. M.
(
1990
).
One of the protein phosphatase 1 isoenzymes in Drosophila is essential for mitosis.
Cell
63
,
33
46
Baker
J.
,
Theurkauf
W. E.
,
Schubiger
G.
(
1993
).
Dynamic changes inmicrotubule configuration correlate with nuclear migration in the preblastoderm Drosophila embryo.
J. Cell Biol
122
,
113
121
Bloom
G. S.
,
Endow
S. A.
(
1995
).
Motor proteins 1: kinesins.
Protein Profile
2
,
1109
1171
Boleti
H.
,
Karsenti
E.
,
Vernos
I.
(
1996
).
Xklp2, a novel Xenopus centrosomal kinesin-like protein required for centrosome separation during mitosis.
Cell
84
,
49
59
Earnshaw
W. C.
,
Cooke
C. A.
(
1991
).
Analysis of the distribution of the INCENPs throughout mitosis reveals the existence of a pathway of structural changes in the chromosomes during metaphase and early events in cleavage furrow formation.
J. Cell Sci
98
,
443
461
Edgar
B. A.
,
O'Farrell
P. H.
(
1989
).
Genetic control of cell division patterns in the Drosophila embryo.
Cell
57
,
177
187
Endow
S. A.
,
Chandra
R.
,
Komma
D. J.
,
Yamamoto
A. H.
,
Salmon
E. D.
(
1994
).
Mutants of the Drosophila ncd microtubule motor protein cause centrosomal and spindle pole defects in mitosis.
J. Cell Sci
107
,
859
867
Endow
S. A.
,
Kang
S. J.
,
Satterwhite
L. L.
,
Rose
M. D.
,
Skeen
V. P.
,
Salmon
E. D.
(
1994
).
Yeast Kar3 is a minus-end microtubule motor protein that destabilizes microtubules preferentially at the minus ends.
EMBO J
13
,
2708
2713
Gatti
M.
,
Baker
B. S.
(
1989
).
Genes controlling essential cell-cycle functions in Drosophila melanogaster.
Genes Dev
3
,
438
453
Glover
D. M.
(
1989
).
Mitosis in Drosophila.
J. Cell Sci
92
,
137
146
Glover
D. M.
,
Leibowitz
M. H.
,
McLean
D. A.
,
Parry
H.
(
1995
).
Mutations in aurora prevent centrosome separation leading to the formation of monopolar spindles.
Cell
81
,
95
105
Hatsumi
M.
,
Endow
S. A.
(
1992
).
The Drosophila ncd microtubule motor protein is spindle-associated in meiotic and mitotic cells.
J. Cell Sci
103
,
1013
1020
Hatsumi
M.
,
Endow
S. A.
(
1992
).
Mutants of the microtubule motor protein, nonclaret disjunctional, affect spindle structure and chromosome movement in meiosis and mitosis.
J. Cell Sci
101
,
547
559
Heck
M. M. S.
,
Pereira
A.
,
Pesavento
P.
,
Yannoni
Y.
,
Spradling
A. C.
,
Goldstein
L. S. B.
(
1993
).
The kinesin-like protein KLP61F is essential for mitosis in Drosophila.
J. Cell Biol
123
,
665
679
Heim
R.
,
Cubitt
A. B.
,
Tsien
R. Y.
(
1995
).
Improved green fluorescence.
Nature
373
,
663
664
Hyman
A.
,
Drechsel
D.
,
Kellogg
D.
,
Salser
S.
,
Sawin
K.
,
Steffen
P.
,
Wordeman
L.
,
Mitchison
T.
(
1991
).
Preparation of modified tubulins.
Meth. Enzymol
196
,
478
485
Karess
R. E.
,
Chang
X. J.
,
Edwards
K. A.
,
Kulkarni
S.
,
Aguilera
I.
,
Kiehart
K. P.
(
1991
).
The regulatory light chain of nonmuscle myosin is encoded by spaghetti-squash, a gene required for cytokinesis in Drosophila.
Cell
65
,
1177
1189
Komma
D. J.
,
Horne
A. S.
,
Endow
S. A.
(
1991
).
Separation of meiotic and mitotic effects of claret nondisjunctional on chromosome segregation in Drosophila.
EMBO J
10
,
419
424
Lewis
E. B.
,
Gencarella
W.
(
1952
).
Claret and non-disjunction in Drosophila melanogaster.
Genetics
37
,
600
601
Llamazares
S.
,
Moreira
M. A.
,
Tavares
A.
,
Girdham
C.
,
Gonzalez
C.
,
Karess
R. E.
,
Glover
D. M.
,
Sunkel
C. E.
(
1991
).
polo encodes a protein kinase homologue required for mitosis in Drosophila.
Genes Dev
5
,
2153
2164
Lombillo
V. A.
,
Nislow
C.
,
Yen
T. J.
,
Gelfand
V. I.
,
McIntosh
J. R.
(
1995
).
Antibodies to the kinesin motor domain and CENP-E inhibit microtubule depolymerization-dependent motion of chromosomes in vitro.
J. Cell Biol
128
,
107
115
Lombillo
V. A.
,
Stewart
R. J.
,
McIntosh
J. R.
(
1995
).
Minus-end-directed motion of kinesin-coated microspheres driven by microtubule depolymerization.
Nature
373
,
161
164
Mayer-Jaekel
R. E.
,
Ohkura
H.
,
Gomes
R.
,
Sunkel
C. E.
,
Baumgartner
S.
,
Hemmings
B. A.
,
Glover
D. M.
(
1993
).
The 55 kd regulatory subunit of Drosophila protein phosphatase 2A is required for anaphase.
Cell
72
,
621
633
Minden
J. S.
,
Agard
D. A.
,
Sedat
J. W.
,
Alberts
B. M.
(
1989
).
Direct cell lineage analysis in Drosophila melanogaster by time-lapse, three-dimensional optical microscopy of living embryos.
J. Cell Biol
109
,
505
516
Nelson
C. R.
,
Szauter
P.
(
1992
).
Timing of mitotic chromosome loss caused by the ncd mutation of Drosophila melanogaste r.
Cell Motil. Cytoskel
23
,
34
44
Portin
P.
(
1978
).
Studies on gynandromorphs induced with the claret-nondisjunctional mutation of Drosophila melanogaster. An approach to the timing of chromosome loss in cleavage mitoses.
Heredity
41
,
193
203
Sawin
K. E.
,
LeGuellec
K.
,
Philippe
M.
,
Mitchison
T. J.
(
1992
).
Mitotic spindle organization by a plus-end-directed microtubule motor.
Nature
359
,
540
543
Sullivan
W.
,
Minden
J. S.
,
Alberts
B. M.
(
1990
).
daughterless-abo-like, a Drosophila maternal-effect mutation that exhibits abnormal centrosome separation during the late blastoderm divisions.
Development
110
,
311
323
Theurkauf
W. E.
(
1992
).
Behavior of structurally divergent-tubulin isotypes during Drosophila embryogenesis: evidence for post-translational regulation of isotype abundance.
Dev. Biol
154
,
205
217
Valdes-Perez
R. E.
,
Minden
J. S.
(
1995
).
Drosophila melanogaster syncytial nuclear divisions are patterned: time-lapse images, hypothesis and computational evidence.
J. Theoret. Biol
175
,
525
532
Walczak
C. E.
,
Mitchison
T. J.
,
Desai
A.
(
1996
).
XKCM1: a Xenopus kinesin-related protein that regulates microtubule dynamics during mitotic spindle assembly.
Cell
84
,
37
47
Wordeman
L.
,
Mitchison
T. J.
(
1995
).
Identification and partial characterization of mitotic centromere-associated kinesin, a kinesin-related protein that associates with centromeres during mitosis.
J. Cell Biol
128
,
95
105
Yamamoto
A. H.
,
Komma
D. J.
,
Shaffer
C. D.
,
Pirrotta
V.
,
Endow
S. A.
(
1989
).
The claret locus in Drosophila encodes products required for eyecolor and for meiotic chromosome segregation.
EMBO J
8
,
3543
3552
Yen
T. J.
,
Li
G.
,
Schaar
B. T.
,
Szilak
I.
,
Cleveland
D. W.
(
1992
).
CENP-E is a putative kinetochore motor that accumulates just before mitosis.
Nature
359
,
536
539
This content is only available via PDF.