Eukaryotic Cell
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
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 arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kumar, P.
Right arrow Articles by Wang, C. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kumar, P.
Right arrow Articles by Wang, C. C.

 Previous Article  |  Next Article 

Eukaryotic Cell, January 2006, p. 92-102, Vol. 5, No. 1
1535-9778/06/$08.00+0     doi:10.1128/EC.5.1.92-102.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Dissociation of Cytokinesis Initiation from Mitotic Control in a Eukaryote{dagger}

Praveen Kumar and C. C. Wang*

Department of Pharmaceutical Chemistry, UCSF, San Francisco, California 94143-2280

Received 11 August 2005/ Accepted 17 October 2005

Cytokinesis is initiated only after mitotic exit in eukaryotes. However, in the insect (procyclic) form of an ancient protist, Trypanosoma brucei, a blockade at the G2/M checkpoint results in an enrichment of anucleate cells (zoids), suggesting separated regulations between mitosis and cytokinesis (X. Tu and C. C. Wang, J. Biol. Chem. 279:20519-20528, 2004). Polo-like kinases (Plks) are known to play critical roles in controlling both mitosis and cytokinesis. A single Plk homologue in T. brucei, TbPLK, was found to be capable of complementing the Plk (Cdc5) functions in Saccharomyces cerevisiae, thus raising the question of how it may function in the trypanosome with cytokinesis dissociated from mitosis. Depletion of TbPLK in the procyclic form of T. brucei by RNA interference resulted in growth arrest with accumulation of multiple nuclei, kinetoplasts, basal bodies, and flagella in approximately equal numbers among individual cells. There were, however, few zoids detectable, indicating inhibited cytokinesis with unblocked mitosis and kinetoplast segregation. TbPLK is thus apparently involved only in initiating cytokinesis in T. brucei. Overexpression of TbPLK in the trypanosome did not affect cell growth, but 13% of the resulting population was in the zoid form, suggesting runaway cytokinesis. An immunofluorescence assay indicated that TbPLK was localized in a chain of likely flagellum attachment zones in the cytoskeleton. In a dividing cell, a new line of such zones appeared closely paralleling the existing one, which could constitute the cleavage furrow. An exposed region of TbPLK at the anterior tip of the cell may provide the trigger of cytokinesis. Taken together, our results revealed a novel mechanism of cytokinesis initiation in the trypanosome that may serve as a useful model for further in-depth investigations.

* Corresponding author. Mailing address: Department of Pharmaceutical Chemistry, UCSF, San Francisco, CA 94143-2280. Phone: (415) 476-1321. Fax: (415) 476-3382. E-mail: ccwang{at}cgl.ucsf.edu.

{dagger} Supplemental material for this article may be found at http://ec.asm.org/.

Eukaryotic Cell, January 2006, p. 92-102, Vol. 5, No. 1
1535-9778/06/$08.00+0     doi:10.1128/EC.5.1.92-102.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Appl. Environ. Microbiol. Infect. Immun. J. Bacteriol.
Mol. Cell Biol. Microbiol. Mol. Biol. Rev. ALL ASM JOURNALS
Copyright © 2006 by the American Society for Microbiology.