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Production of Xenopus tropicalis Egg Extracts to Identify Microtubule-associated RNAs
10:01

Production of Xenopus tropicalis Egg Extracts to Identify Microtubule-associated RNAs

Published on: June 27, 2013

Katanin is responsible for the M-phase microtubule-severing activity in Xenopus eggs

F J McNally1, S Thomas

  • 1Section of Molecular and Cellular Biology, University of California, Davis, Davis, California 95616, USA. fjmcnally@ucdavis.edu

Molecular Biology of the Cell
|July 11, 1998
PubMed

Insights

Katanin is the primary microtubule-severing protein responsible for mitotic changes in Xenopus egg extracts. This protein is crucial for microtubule organization at mitotic spindle poles and may have additional functions in the brain.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Microtubules are essential for cell division and membrane organization, requiring dynamic rearrangements throughout the cell cycle.
  • Previous studies identified M-phase microtubule-severing activity in Xenopus egg extracts, implicating a key protein in cell cycle-dependent microtubule regulation.
  • The discovery of multiple severing proteins (p56, EF1alpha, katanin) complicated understanding, as none were directly activated by cyclin B/cdc2.

Purpose of the Study:

  • To identify the specific microtubule-severing protein responsible for M-phase activity in Xenopus egg extracts.
  • To elucidate the role of katanin in mitotic microtubule organization and dynamics.
  • To investigate potential non-mitotic functions of katanin.

Main Methods:

  • Immunodepletion using antibodies specific to a vertebrate katanin homologue.
  • Assay of microtubule-severing activity in Xenopus egg extracts.
  • Immunofluorescence microscopy to determine katanin localization in Xenopus A6 cells and human fibroblasts.

Main Results:

  • Immunodepletion of katanin significantly reduced M-phase microtubule-severing activity in Xenopus egg extracts, identifying it as the major contributor.
  • Katanin localizes to microtubule-dependent structures at mitotic spindle poles in both Xenopus and human cells, suggesting a role in microtubule disassembly.
  • Katanin was also detected in adult mouse brain, indicating potential functions beyond mitosis.

Conclusions:

  • Vertebrate katanin is the primary mediator of M-phase microtubule severing activity, crucial for mitotic microtubule reorganization.
  • Katanin plays a specific role in microtubule dynamics at mitotic spindle poles.
  • The presence of katanin in the brain suggests broader biological functions independent of its mitotic role.

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