These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: MICROTUBULE ORGANIZATION 1 regulates structure and function of microtubule arrays during mitosis and cytokinesis in the Arabidopsis root.
    Author: Kawamura E, Himmelspach R, Rashbrooke MC, Whittington AT, Gale KR, Collings DA, Wasteneys GO.
    Journal: Plant Physiol; 2006 Jan; 140(1):102-14. PubMed ID: 16377747.
    Abstract:
    MICROTUBULE ORGANIZATION 1 (MOR1) is a plant member of the highly conserved MAP215/Dis1 family of microtubule-associated proteins. Prior studies with the temperature-sensitive mor1 mutants of Arabidopsis (Arabidopsis thaliana), which harbor single amino acid substitutions in an N-terminal HEAT repeat, proved that MOR1 regulates cortical microtubule organization and function. Here we demonstrate by use of live cell imaging and immunolabeling that the mor1-1 mutation generates specific defects in the microtubule arrays of dividing vegetative cells. Unlike the universal cortical microtubule disorganization in elongating mor1-1 cells, disruption of mitotic and cytokinetic microtubule arrays was not detected in all dividing cells. Nevertheless, quantitative analysis identified distinct defects in preprophase bands (PPBs), spindles, and phragmoplasts. In nearly one-half of dividing cells at the restrictive temperature of 30 degrees C, PPBs were not detected prior to spindle formation, and those that did form were often disrupted. mor1-1 spindles and phragmoplasts were short and abnormally organized and persisted for longer times than in wild-type cells. The reduced length of these arrays predicts that the component microtubule lengths are also reduced, suggesting that microtubule length is a critical determinant of spindle and phragmoplast structure, orientation, and function. Microtubule organizational defects led to aberrant chromosomal arrangements, misaligned or incomplete cell plates, and multinucleate cells. Antiserum raised against an N-terminal MOR1 sequence labeled the full length of microtubules in interphase arrays, PPBs, spindles, and phragmoplasts. Continued immunolabeling of the disorganized and short microtubules of mor1-1 at the restrictive temperature demonstrated that the mutant mor1-1(L174F) protein loses function without dissociating from microtubules, providing important insight into the mechanism by which MOR1 may regulate microtubule length.
    [Abstract] [Full Text] [Related] [New Search]