|
|
|
|||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||

Section of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
* Present address: Exelixis, South San Francisco, CA 94080, USA
Author for correspondence (e-mail: lsrose{at}ucdavis.edu)
Accepted 1 July 2002
Asymmetric cell division depends on coordinating the position of the mitotic spindle with the axis of cellular polarity. We provide evidence that LET-99 is a link between polarity cues and the downstream machinery that determines spindle positioning in C. elegans embryos. In let-99 one-cell embryos, the nuclear-centrosome complex exhibits a hyperactive oscillation that is dynein dependent, instead of the normal anteriorly directed migration and rotation of the nuclear-centrosome complex. Furthermore, at anaphase in let-99 embryos the spindle poles do not show the characteristic asymmetric movements typical of wild type animals. LET-99 is a DEP domain protein that is asymmetrically enriched in a band that encircles P lineage cells. The LET-99 localization pattern is dependent on PAR polarity cues and correlates with nuclear rotation and anaphase spindle pole movements in wild-type embryos, as well as with changes in these movements in par mutant embryos. In particular, LET-99 is uniformly localized in one-cell par-3 embryos at the time of nuclear rotation. Rotation fails in spherical par-3 embryos in which the eggshell has been removed, but rotation occurs normally in spherical wild-type embryos. The latter results indicate that nuclear rotation in intact par-3 embryos is dictated by the geometry of the oblong egg and are consistent with the model that the LET-99 band is important for rotation in wild-type embryos. Together, the data indicate that LET-99 acts downstream of PAR-3 and PAR-2 to determine spindle positioning, potentially through the asymmetric regulation of forces on the spindle.
Key words: Spindle orientation, Asymmetric division, Microtubules, Embryo, DEP domain, C. elegans
This article has been cited by other articles:
![]() |
H. Zhang, J. M. Squirrell, and J. G. White RAB-11 Permissively Regulates Spindle Alignment by Modulating Metaphase Microtubule Dynamics in Caenorhabditis elegans Early Embryos Mol. Biol. Cell, June 1, 2008; 19(6): 2553 - 2565. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. M. Rivers, S. Moreno, M. Abraham, and J. Ahringer PAR proteins direct asymmetry of the cell cycle regulators Polo-like kinase and Cdc25 J. Cell Biol., March 5, 2008; 180(5): 877 - 885. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Nishi, E. Rogers, S. M. Robertson, and R. Lin Polo kinases regulate C. elegans embryonic polarity via binding to DYRK2-primed MEX-5 and MEX-6 Development, February 15, 2008; 135(4): 687 - 697. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. K. Baruni, E. M. Munro, and G. von Dassow Cytokinetic furrowing in toroidal, binucleate and anucleate cells in C. elegans embryos J. Cell Sci., February 1, 2008; 121(3): 306 - 316. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Kimura and S. Onami Local cortical pulling-force repression switches centrosomal centration and posterior displacement in C. elegans J. Cell Biol., December 31, 2007; 179(7): 1347 - 1354. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. V. Dinkelmann, H. Zhang, A. R. Skop, and J. G. White SPD-3 Is Required for Spindle Alignment in Caenorhabditis elegans Embryos and Localizes to Mitochondria Genetics, November 1, 2007; 177(3): 1609 - 1620. [Abstract] [Full Text] [PDF] |
||||
![]() |
J.-C. Wu and L. S. Rose PAR-3 and PAR-1 Inhibit LET-99 Localization to Generate a Cortical Band Important for Spindle Positioning in Caenorhabditis elegans Embryos Mol. Biol. Cell, November 1, 2007; 18(11): 4470 - 4482. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Couwenbergs, J.-C. Labbe, M. Goulding, T. Marty, B. Bowerman, and M. Gotta Heterotrimeric G protein signaling functions with dynein to promote spindle positioning in C. elegans J. Cell Biol., October 8, 2007; 179(1): 15 - 22. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. B. Goulding, J. C. Canman, E. N. Senning, A. H. Marcus, and B. Bowerman Control of nuclear centration in the C. elegans zygote by receptor-independent G{alpha} signaling and myosin II J. Cell Biol., September 24, 2007; 178(7): 1177 - 1191. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Strauss, R. J. Adams, and N. Papalopulu A default mechanism of spindle orientation based on cell shape is sufficient to generate cell fate diversity in polarised Xenopus blastomeres Development, October 1, 2006; 133(19): 3883 - 3893. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Leslie Centrosome choreography J. Cell Biol., January 30, 2006; 172(3): 328 - 328. [Full Text] [PDF] |
||||
![]() |
D. J. Schmidt, D. J. Rose, W. M. Saxton, and S. Strome Functional Analysis of Cytoplasmic Dynein Heavy Chain in Caenorhabditis elegans with Fast-acting Temperature-sensitive Mutations Mol. Biol. Cell, March 1, 2005; 16(3): 1200 - 1212. [Abstract] [Full Text] [PDF] |
||||
![]() |
M.-F. B. Tsou, A. Hayashi, and L. S. Rose LET-99 opposes G{alpha}/GPR signaling to generate asymmetry for spindle positioning in response to PAR and MES-1/SRC-1 signaling Development, December 1, 2003; 130(23): 5717 - 5730. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. C. Bergmann, M. Lee, B. Robertson, M.-F. B. Tsou, L. S. Rose, and W. B. Wood Embryonic handedness choice in C. elegans involves the G{alpha} protein GPA-16 Development, December 1, 2003; 130(23): 5731 - 5740. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. J. Wright and C. P. Hunter Mutations in a {beta}-Tubulin Disrupt Spindle Orientation and Microtubule Dynamics in the Early Caenorhabditis elegans Embryo Mol. Biol. Cell, November 1, 2003; 14(11): 4512 - 4525. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Colombo, S. W. Grill, R. J. Kimple, F. S. Willard, D. P. Siderovski, and P. Gonczy Translation of Polarity Cues into Asymmetric Spindle Positioning in Caenorhabditis elegans Embryos Science, June 20, 2003; 300(5627): 1957 - 1961. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. F. Severson and B. Bowerman Myosin and the PAR proteins polarize microfilament-dependent forces that shape and position mitotic spindles in Caenorhabditis elegans J. Cell Biol., April 14, 2003; 161(1): 21 - 26. [Abstract] [Full Text] [PDF] |
||||
![]() |
M.-F. B. Tsou, W. Ku, A. Hayashi, and L. S. Rose PAR-dependent and geometry-dependent mechanisms of spindle positioning J. Cell Biol., March 17, 2003; 160(6): 845 - 855. [Abstract] [Full Text] [PDF] |
||||