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Abstract Detail



Cell biology

Fujita, Miki [1], Wark, Krystal [2], Wang, James [1], Wasteneys, Geoffrey O. [3].

Live-cell imaging of fluorescently-tagged COBRA GPI-anchored protein in elongating cells of Arabidopsis thaliana.

COBRA (COB) is a glycosylphosphatidylinositol (GPI)-anchored protein that is required for directional cell expansion. Loss-of-function cobra mutants have swollen roots and produce less cellulose. Recent studies have shown that COB binds to cellulose through a cellulose-binding domain and influences cellulose biosynthesis. Its function, however, remains to be elucidated. For the current study, we generated transgenic lines that express either COB-citrineYFP (cYFP) or tagRFP that partially rescued the cob-4 null mutant phenotypes. COB-cYFP was expressed in all root cell types and etiolated hypocotyl cells. In rapidly elongating cells, COB-cYFP is highly expressed and majority of COB-cYFP is found in Golgi. In contrast to published immunolabelling studies that demonstrated COB localization both at the plasma membrane and in the cell wall, COB-cYFP was not detected in the cell wall of plasmolyzed cells. We extracted COB-cYFP from plants and detected it in the microsomal fraction, indicating its localization in endomembrane but not in the cell wall protein fraction. cYFP may be interfering with COBRA function and localization, resulting in the partial rescue of the null mutant. Using either spinning disk confocal microscopy or near total internal reflection fluorescence (TIRF) microscopy, we observed two populations of COB-cYFP present as small puncta; ones moving slowly in linear trajectories and the others moving quickly in a linear manner. The motility of the rapidly moving puncta suggests that they are cytoskeleton-associated vesicles.


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1 - University of British Columbia, Botany
2 - University or British Columbis, Botany
3 - University of British Columbia, Botany, 3529-6270 University Blvd., Vancouver, BC, V6T1Z4, Canada

Keywords:
Cellulose
plant growth
microtubule
COBRA.

Presentation Type: Oral Paper:Papers for Topics
Session: 58
Location: Salon 17/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 8:30 AM
Number: 58003
Abstract ID:1156
Candidate for Awards:None


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