spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online 21 May 2008
doi: 10.1242/jcs.011825

Journal of Cell Science 121, 1973-1980 (2008)
Published by The Company of Biologists 2008
This Article
Right arrow Summary Freely available
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplementary Material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Daga, R. R.
Right arrow Articles by Nurse, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Daga, R. R.
Right arrow Articles by Nurse, P.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Interphase microtubule bundles use global cell shape to guide spindle alignment in fission yeast

Rafael R. Daga1,2,* and Paul Nurse1

1 Rockefeller University, 1234 York Avenue, New York, NY 10021, USA
2 Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Cientificas, Universidad Pablo de Olavide, Carretera de Utrera km 1, 41013 Sevilla, Spain


Figure 1
View larger version (28K):
[in this window]
[in a new window]

  		Fig. 1. Microtubule cytoskeleton is required for spindle alignment. (A) Scheme of a S. pombe cell with a misaligned spindle. The angle is that formed between the mitotic spindle axis and the long axis of the cell (both axes are indicated with arrows). (B) Percentage of wild-type haploid and diploid control cells, MBC (25 µg/ml) or Latrunculin A (50 µM) treated cells, and mto1{Delta} and tip1{Delta} cells, showing the angle of the mitotic spindle relative to the long axis of the cell. The range of mitotic spindle angles of mto1{Delta} cells MBC-treated cells and tip1{Delta} cells were significantly different to wild-type cells (P<0.001) but no significant difference from the wild type was seen in Latrunculin-A-treated cells (P<0.1) or diploid cells (P<0.2).

 

Figure 2
View larger version (42K):
[in this window]
[in a new window]

  		Fig. 2. Microtubules and microtubule-SPB attachment are required for proper spindle alignment. (A) Scheme showing the SPB trajectory from position A at time 0 to position B at time 1. (B) Overlaid images showing SPB position during a window of time ranging from 25 to 28 minutes in wild-type control cells, MBC (25 µg/ml) or Latrunculin A (50 µM) treated cells, and mto1{Delta} cells expressing the SPB marker Sid2-GFP. Arrowheads denote the overlaid SPB trajectory. The asterisk denotes a cell in mitosis. Dashed lines indicate the cell outline. (C) Overlaid images showing the SPB position during the indicated time interval followed by images taken one or two minutes before SPB separation in wild-type control cells, MBC-treated cells (25 µg/ml), mto1{Delta} cells, and the cell morphology mutants tea1{Delta} and orb6-25, expressing sid2-GFP. Arrowheads indicate the initial SPB separation.

 

Figure 3
View larger version (41K):
[in this window]
[in a new window]

  		Fig. 3. Initial SPB separation at mitosis occurs along the same axis as the last SPB movement during interphase. (A) Scheme showing the angles measured. The angles of the SPBs trajectory with respect to the axis of SPB separation were measured between consecutive time points. (B) Graphs showing these angles in three representative cells of the indicated strains. The asterisks indicate the angle of the last SPB trajectory 1 minute before mitosis for every cell type. Note that the angle of SPB separation is the base comparison and so is zero. (C) Table of spindle orientation parameters in the wild type and the morphology mutants orb6-25 and tea1{Delta}. Average angle of SPB oscillation, the difference between the angle of the last SPB trajectory and initial angle of SPB separation, and average angle of spindle alignment relative to the long axis of the cells are all shown in the indicated strains. n, number of cells analyzed.

 

Figure 4
View larger version (102K):
[in this window]
[in a new window]

  		Fig. 4. Interphase MT disassembly and the formation of the mitotic spindle. Wild-type cells expressing GFP-atb2 and sid2-TOMATO (tubulin and SPB markers, respectively) progressing from interphase to mitosis were recorded in multiple focal planes. Maximum projections of eight z-series are shown. Arrowheads indicate the incipient formation of the mitotic spindle. Arrows indicate interphase MTs that are being disassembled as the intranuclear mitotic spindle is formed.

 

Figure 5
View larger version (75K):
[in this window]
[in a new window]

  		Fig. 5. The initial pre-alignment mechanism is critical for cell survival when the spindle length is compromised. (A) Wild-type cells expressing sid2-GFP and rlc1-GFP as SPB and actomyosin ring marker, respectively, were treated with 25 µg/ml of the microtubule-depolymerizing drug Carbendazim (MBC) to inhibit the fully extension of the mitotic spindle. The upper panel shows a cell that initiates SPB separation at mitosis aligned with the cellular long axis. The lower panel shows a cell that initiated SPB separation misaligned with the cellular axis. Arrowhead indicates SPBs positions over time whereas the arrows indicate the position of the contractile actomyosin ring at the division site. (B) Quantification of the result shown in A. Graph showing the correlation between initial angle of SPB separation and the frequency of finding the two poles at one side of the division plane.

 

Figure 6
View larger version (20K):
[in this window]
[in a new window]

  		Fig. 6. Model of spindle alignment in S. pombe. (1) Interphase MTs attached to the duplicated SPB align the axis of the duplicated SPBs with the axis of the cell. The drawing at the bottom left shows duplicated SPBs containing a long and a short axis. The distances shown are approximate. (2) Microtubule dynamics is important to align the interphase MTs with the cellular axis. When MTs are too short they are often misaligned with the cellular axis and consequently the mitotic spindle will be misaligned. (3) The attachment between the mitotic spindle and the interphase MTs is critical to transmit the spatial information obtained by dynamic MTs to the duplicated SPBs at the nuclear envelope.

 

Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?



© The Company of Biologists Ltd 2008