Spindle poles are discernible by light microscopy as the sites where microtubules converge at the ends of both mitotic and meiotic spindles. In most cell types centrosomes are present at spindle poles due to their dominant role in microtubule nucleation. However, in some specialized cell types microtubules converge into spindle poles in the absence of centrosomes. Thus, spindle poles in centrosomal and acentrosomal cell types are structurally different, and it is this structural dichotomy that has created confusion as to the mechanism by which microtubules are organized into spindle poles. This review summarizes a series of recent articles that begin to resolve this confusion by demonstrating that spindle poles are organized through a common mechanism by a conserved group of non-centrosomal proteins in the presence or absence of centrosomes.
REFERENCES
Aist
J. R.
, Bayles
C. J.
, Tao
W.
, Berns
M. W.
(1991
). Direct experimental evidence for the existence, structrual basis and function of astral forces during anaphase B in vivo.
J. Cell Sci
100
, 279
–288
Barton
N. R.
, Goldstein
L. S. B.
(1996
). Going mobile: microtubule motors and chromosome segregation.
Proc. Nat. Acad. Sci USA
93
, 1735
–1742
Blangy
A.
, Lane
H. A.
, d'Herin
P.
, Harper
M.
, Kress
M.
, Nigg
E. A.
(1995
). Phosphorylation by p34cdc2 regulates spindle association of human Eg5, a kinesin-related motor essential for bipolar spindle formation in vivo.
Cell
83
, 1159
–1169
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
Carminati
J. L.
, Stearns
T.
(1997
). Microtubules orient the mitotic spindle in yeast through dynein-dependent interactions with the cell cortex.
J. Cell Biol
138
, 629
–642
Cottingham
F. R.
, Hoyt
M. A.
(1997
). Mitotic spindle positioning in Saccharomyces cerevisiae is accomplished by antagonistically acting microtubule motor proteins.
J. Cell Biol
138
, 1041
–1054
DeBrabander
M.
, Geuens
G.
, Nuydens
R.
, Willebrords
R.
, DeMey
J.
(1981
). Taxol induces the assembly of free microtubules in living cells and blocks the organizing capacity of the centrosomes and kinetochores.
Proc. Nat. Acad. Sci. USA
78
, 5608
–5612
DeZwann
T. M.
, Ellinson
E.
, Pellman
D.
, Roof
D. M.
(1997
). Kinesin-related KIP3 of Saccharomyces cerevisiae is required for a distinct step in nuclear migration.
J. Cell Biol
138
, 1023
–1040
Echeverri
C. J.
, Paschal
B. M.
, Vaughan
K. T.
, Vallee
R. B.
(1996
). Molecular characterization of the 50-kD subunit of dynactin reveals function for the complex in chromosome alignment and spindle organization during mitosis.
J. Cell Biol
132
, 617
–633
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
Gaglio
T.
, Saredi
A.
, Compton
D. A.
(1995
). NuMA is required for the organization of microtubules into aster-like mitotic arrays.
J. Cell Biol
131
, 693
–708
Gaglio
T.
, Saredi
A.
, Bingham
J. B.
, Hasbani
M. J.
, Gill
S. R.
, Schroer
T. A.
, Compton
D. A.
(1996
). Opposing motor activities are required for the organization of the mammalian mitotic spindle pole.
J. Cell Biol
135
, 399
–414
Gaglio
T.
, Dionne
M. A.
, Compton
D. A.
(1997
). Mitotic spindle polesare organized by structural and motor proteins in addition to centrosomes.
J. Cell Biol
138
, 1055
–1066
Gill
S. R.
, Schroer
T. A.
, Szilak
I.
, Steuer
E. R.
, Sheetz
M. P.
, Cleveland
D. W.
(1991
). Dynactin, a conserved, ubiquitously expressed component of an activator of vesicle motility mediated by cytoplasmic dynein.
J. Cell Biol
115
, 1639
–1650
Heald
R.
, Tournebize
R.
, Blank
T.
, Sandaltzopoulos
R.
, Becker
P.
, Hyman
A.
, Karsenti
E.
(1996
). Self-organization of microtubules into bipolar spindle around artificial chromosomes in Xenopus egg extracts.
Nature
382
, 420
–425
Heald
R.
, Tournebize
R.
, Habermann
A.
, Karsenti
E.
, Hyman
A.
(1997
). Spindle assembly in Xenopus egg extracts: respective roles of centrosomes and microtubule self-organization.
J. Cell Biol
138
, 615
–628
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
Kallajoki
M.
, Weber
K.
, Osborn
M.
(1992
). Ability to organize microtubules in taxol-treated mitotic PtK2 cells goes with the SPN antigen and not with the centrosome.
J. Cell Sci
102
, 91
–102
Kashina
A. S.
, Baskin
R. J.
, Cole
D. G.
, Wedaman
K. P.
, Saxton
W. M.
, Scholey
J. M.
(1996
). A bipolar kinesin.
Nature
379
, 270
–272
Kirschner
M.
, Mitchison
T. J.
(1986
). Beyond self-assembly: from microtubule to morphogenesis.
Cell
45
, 329
–342
Kuriyama
R.
, Kofron
M.
, Essner
R.
, Kato
T.
, Dragas-Granoic
S.
, Omoto
C. K.
, Khodjakov
A.
(1995
). Characterization of a minus end-directed kinesin-like motor protein from cultured mammalian cells.
J. Cell Biol
129
, 1049
–1059
Lydersen
B. K.
, Pettijohn
D. E.
(1980
). Human specific nuclear protein that associates with the polar region of the mitotic apparatus: distribution in a human/hamster hybrid cell.
Cell
22
, 489
–499
Maniotis
A.
, Schliwa
M.
(1991
). Microsurgical removal of centrosomes blocks cell reproduction and centriole generation in BSC-1 cells.
Cell
67
, 495
–504
Mastronarde
D. N.
, McDonald
K. L.
, Ding
R.
, McIntosh
J. R.
(1993
). Interpolar spindle microtubules in PTK cells.
J. Cell Biol
123
, 1475
–1489
Matthies
H. J. G.
, McDonald
H. B.
, Goldstein
L. S. B.
, Theurkauf
W. E.
(1996
). Anastral meiotic spindle morphogenesis: role of the non-claret disjunctional kinesin-like protein.
J. Cell Biol
134
, 455
–464
Mazia
D.
(1984
). Centrosomes and mitotic poles.
Exp. Cell Res
153
, 1
–15
McDonald
H. B.
, Stewart
R. J.
, Goldstein
L. S. B.
(1990
). The kinesin-like ncd protein of Drosophila is a minus end-directed microtubule motor.
Cell
63
, 1159
–1165
McDonald
K. L.
, O'Toole
E. T.
, Mastronarde
D. N.
, McIntosh
J. R.
(1992
). Kinetochore microtubules in PTK cells.
J. Cell Biol
118
, 369
–383
McKim
K. S.
, Hawley
R. S.
(1995
). Chromosomal control of meiotic cell division.
Science
270
, 1595
–1601
McNally
F. J.
, Okawa
K.
, Iwamatsu
A.
, Vale
R. D.
(1996
). Katanin, the microtubule severing ATPase, is concentrated at centrosomes.
J. Cell Sci
109
, 561
–567
Merdes
A.
, Cleveland
D. W.
(1997
). Pathways of spindle pole formation: different mechanisms; conserved components.
J. Cell Biol
138
, 953
–956
Merdes
A.
, Ramyar
K.
, Vechio
J. D.
, Cleveland
D. W.
(1996
). A complex of NuMA and cytoplasmic dynein is essential for mitotic spindle assembly.
Cell
87
, 447
–458
Mitchison
T. J.
, Salmon
E. D.
(1992
). Poleward kinetochore fiber movement occurs during both metaphase and anaphase-A in newt lung cell mitosis.
J. Cell Biol
119
, 569
–582
Moritz
M.
, Braunfeld
M. B.
, Sedat
J. W.
, Alberts
B.
, Agard
D. A.
(1995
). Microtubule nucleation by-tubulin-containing rings in the centrosome.
Nature
378
, 637
–640
Nicklas
R. B.
(1989
). The motor for poleward chromosome movement in anaphase is in or near the kinetochore.
J. Cell Biol
109
, 2245
–2255
Nicklas
R. B.
, Lee
G. M.
, Rieder
C. L.
, Rupp
G.
(1989
). Mechanically cut mitotic spindles: clean cuts and stable microtubules.
J. Cell Sci
94
, 415
–423
Pfarr
C. M.
, Cove
M.
, Grissom
P. M.
, Hayes
T. S.
, Porter
M. E.
, Mcintosh
J. R.
(1991
). Cytoplasmic dynein is localized to kinetochores during mitosis.
Nature
345
, 263
–265
Rieder
C. L.
(1981
). The structure of the cold-stable kinetochore fiber in metaphase PtK1 cells.
Chromosoma
84
, 145
–158
Rodionov
V. I.
, Borisy
G. G.
(1997
). Self-centering activity of cytoplasm.
Nature
386
, 170
–173
Saredi
A.
, Howard
L.
, Compton
D. A.
(1996
). NuMA assembles into an extensive filamentous structure when expressed in the cell cytoplasm.
J. Cell Sci
109
, 619
–630
Saredi
A.
, Howard
L.
, Compton
D. A.
(1997
). Phosphorylation regulates the assembly of NuMA in a mammalian mitotic extract.
J. Cell Sci
110
, 1287
–1297
Sawin
K. E.
, Endow
S. A.
(1993
). Meiosis, mitosis and microtubule motors.
BioEssays
15
, 399
–407
Sawin
K. E.
, LeFuellec
K.
, Philippe
M.
, Mitchison
T. J.
(1992
). Mitotic spindle organization by a plus-end-directed microtubule motor.
Nature
359
, 540
–543
Shaw
S. L.
, Yeh
E.
, Maddox
P.
, Salmon
E. D.
, Bloom
K.
(1997
). Astral microtubule dynamics in yeast: A microtubule-based searching mechanism for spindle orientation and nuclear migration into the bud.
J. Cell Biol
139
, 985
–994
Smirnova
E. A.
, Bajer
A. S.
(1992
). Spindle poles in higher plant mitosis.
Cell Motil. Cytoskel
23
, 1
–7
Steffen
W.
, Fuge
H.
, Dietz
R.
, Bastmeyer
M.
, Muller
G.
(1986
). Aster-free spindle poles in insect spermatocytes: evidence for chromosome-induced spindle formation.
J. Cell Biol
102
, 1679
–1687
Steuer
E. R.
, Schroer
T. A.
, Wordeman
L.
, Sheetz
M. P.
(1991
). Cytoplasmic dynein localizes to mitotic spindles and kinetochores.
Nature
345
, 266
–268
Theurkauf
W. E.
, Hawley
R. S.
(1992
). Meiotic spindle assembly in Drosophila females: behavior of nonexchange chromosomes and the effectsof mutations in the nod kinesin-related protein.
J. Cell Biol
116
, 1167
–1180
Vaisberg
E. A.
, Koonce
M. P.
, McIntosh
J. R.
(1993
). Cytoplasmic dynein plays a role in mammalian mitotic spindle formation.
J. Cell Biol
123
, 849
–858
Verde
F.
, Berrez
J.-M.
, Antony
C.
, Karsenti
E.
(1991
). Taxol-induced microtubule asters in mitotic extracts of Xenopus eggs: requirement for phosphorylated factors and cytoplasmic dynein.
J. Cell Biol
112
, 1177
–1187
Walczak
C. E.
, Mitchison
T. J.
(1996
). Kinesin-related proteins at mitotic spindle poles: function and regulation.
Cell
85
, 943
–946
Walczak
C. E.
, Verma
S.
, Mitchison
T. J.
(1997
). XCTK2: a kinesin-related protein that promotes mitotic spindle assembly in Xenopus laevis egg extracts.
J. Cell Biol
136
, 859
–870
Waters
J. C.
, Salmon
E. D.
(1997
). Pathways of spindle assembly.
Curr. Opin. Cell Biol
9
, 37
–43
Wilson
P. G.
, Fuller
M. T.
, Borisy
G. G.
(1997
). Monastral bipolar spindles: implications for dynamic centrosome organization.
J. Cell Sci
110
, 451
–464
Winey
M.
, Mamay
C. L.
, O'Toole
E. T.
, Mastronarde
D. N.
, Giddings
T. H.
Jr., McDonald
K. L.
, McIntosh
J. R.
(1995
). Three-dimensional ultrastructural analysis of the Saccharomyces cerevisiae mitotic spindle.
J. Cell Biol
129
, 1601
–1615
Wolf
K. W.
, Bastmeyer
M.
(1991
). Cytology of Lepidoptera. V. The microtubule cytoskeleton in eupyrene spermatocytes of Ephestia kuehniella (pyralidae), Inachis io (Nymphalidae), and Orgyia antiqua (Lymantriidae).
Eur. J. Cell Biol
55
, 225
–237
Zhang
D.
, Nicklas
R. B.
(1995
). The impact of chromosomes and centrosomes on spindle assembly as observed in living cells.
J. Cell Biol
129
, 1287
–1300
Zheng
Y.
, Wong
M. L.
, Alberts
B.
, Mitchison
T. J.
(1995
). Nucleation of microtubule assembly by a-tubulin-containing ring complex.
Nature
378
, 578
–583
This content is only available via PDF.
© 1998 by Company of Biologists
1998
-2023JournalMeeting.png?versionId=4193)
-PolarityCFP.png?versionId=4193)
-ECRpage.jpg?versionId=4193)
-CSTW.png?versionId=4193)
-CiliaryVesicles2.jpeg?versionId=4193)
