Molecular Biology of the Cell Sign up for new MBC in Press e-TOCs!

Home Help [Feedback] [For Subscribers] [Archive] [Search] --
QUICK SEARCH:   [advanced]


     

MBC in Press, published online ahead of print September 19, 2007
Mol. Biol. Cell 10.1091/mbc.E07-04-0379

A more recent version of this article appeared on December 1, 2007
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
E07-04-0379v1
18/12/4711    most recent
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 arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ma, C.
Right arrow Articles by Morrissette, N. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ma, C.
Right arrow Articles by Morrissette, N. S.

Submitted on April 27, 2007
Revised on September 6, 2007
Accepted on September 7, 2007

Mutations in {alpha}-Tubulin Confer Dinitroaniline Resistance at a Cost to Microtubule Function

Christopher Ma,*{dagger} Catherine Li,*{dagger} Lakshmi Ganesan,* Jean Oak,* Susan Tsai,* David Sept,{ddagger} and Naomi S. Morrissette*

*Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697; {ddagger}Department of Biomedical Engineering and the Center for Computational Biology, Washington University School of Medicine, St. Louis, MO 63110

Monitoring Editor: Kerry Bloom

Protozoan microtubules are sensitive to disruption by dinitroanilines, compounds that kill intracellular Toxoplasma gondii parasites without affecting microtubules in vertebrate host cells. We previously isolated a number of resistant Toxoplasma lines that harbor mutations to the {alpha}1-tubulin gene. Some of the mutations are localized in or near the M and N loops, domains that coordinate lateral interactions between protofilaments. Other resistance mutations map to a computationally identified binding site beneath the N loop. Allelic replacement of wild-type {alpha}1-tubulin with the individual mutations is sufficient to confer dinitroaniline resistance. Some mutations appear to increase microtubule length, suggesting that they increase subunit affinity. All mutations are associated with replication defects that decrease parasite viability. When parasites bearing the N loop mutation Phe52Tyr are grown without dinitroaniline selection, they spontaneously acquired secondary mutations in the M loop (Ala273Val) or in an {alpha}-tubulin-specific insert that stabilizes the M loop (Asp367Val). Parasites with the double mutations have both reduced resistance and diminished incidence of replication defects, suggesting that the secondary mutations decrease protofilament affinity to increase parasite fitness.

{dagger}These authors contributed equally to this work.

Address correspondence to: Naomi S. Morrissette (nmorriss{at}uci.edu)






Home Help [Feedback] [For Subscribers] [Archive] [Search] --
Copyright © 2007 by The American Society for Cell Biology. Terms of copyright protection, warranties, and disclaimers.