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A more recent version of this article appeared on March 1, 2004
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Submitted on June 11, 2003
Revised on October 15, 2003
Accepted on November 5, 2003
-TUBULIN RESIDUE
1 Department of Biology, Boston College, Chestnut Hill, MA 02467, These authors contributed equally to this work
2 Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, These authors contributed equally to this work
3 Department of Biology, Northeastern University, Boston, MA 02115
4 Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
* Corresponding author. E-mail address: kdowning{at}lbl.gov.
The microtubule cytoskeleton is involved in regulation of cell morphology, differentiation and cell cycle progression. Precisely controlled dynamic properties are required for these microtubule functions. To better understand how tubulins dynamics are embedded in its primary sequence we investigated in vivo the consequences of altering a single, highly conserved residue in
-TUBULIN that lies at the interface between two structural domains. The residue differs between the cold-adapted Antarctic fish and temperate animals in a manner that suggests a role in microtubule stability. Fungi, like the Antarctic fish, have a phenylalanine in this position, while essentially all other animals have tyrosine. We mutated the corresponding residue in fission yeast to tyrosine. Temperature effects were subtle, but time-lapse microscopy of microtubule dynamics revealed reduced depolymerization rates and increased stability. Mitotic exit signaled by breakdown of the mitotic spindle was delayed. In meiosis, microtubules displayed prolonged contact to the cell cortex during horsetail movement, followed by completion of meiosis I but frequent asymmetric failure of meiosis II spindle formation. Our results indicate that depolymerization dynamics modulated through interdomain motion may be important for regulating a subset of plus-end microtubule complexes in Schizosaccharomyces pombe.