FRAP analysis of the stability of the microtubule population along the neurites of chick sensory neurons

Authors

  • Kathryn J. Edson,

    1. Department of Cell Biology and Neuroanatomy, University of Minnesota, Minneapolis
    2. Friedrich-Miescher Institut, Basel, Switzerland
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  • Soo-Siang Lim,

    1. Molecular Biology Laboratory, University of Wisconsin, Madison
    2. Department of Anatomy, Indiana University Medical Center, Indianapolis, Indiana
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  • Gary G. Borisy,

    1. Molecular Biology Laboratory, University of Wisconsin, Madison
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  • Paul C. Letourneau

    Corresponding author
    1. Department of Cell Biology and Neuroanatomy, University of Minnesota, Minneapolis
    • Department of Cell Biology and Neuroanatomy, 4-135 Jackson Hall, University of Minnesota, Minneapolis, MN 55455
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Abstract

In order to study microtubule turnover in elongating neurites, chick embryo sensory neurons were microinjected with x-rhodamine tubulin, and after 6–12 hours, short segments along chosen neurites were photobleached at multiple sites. Previous studies [Lim et al., 1989; 1990] indicated that recovery of fluorescence (FRAP) in neurites occurs by the dynamic turnover of stationary microtubules. In all cases, distal bleached zones recovered fluorescence faster than bleached zones more proximally located along the same neurites. Bleached zones at growth cones completely recovered in 30–40 minutes, while bleached zones located more proximally usually recovered in 50–120 minutes. In the most proximal regions of long neurites, recovery of fluorescence was often incomplete, indicating that a significant fraction of the microtubules in these regions were very stable. These studies indicate that there are differences in microtubule stability along the lenght of growing neurites. These differences may arise from the combined effects of (1) modifications that stabilize and lengthen microtubules in maturing neurites and (2) the dynamic instability of the distally oriented microtubule plus ends. © 1993 Wiley-Liss, Inc.

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