The structure of the cold-stable kinetochore fiber in metaphase PtK1 cells

Chromosoma. 1981;84(1):145-58. doi: 10.1007/BF00293368.


When metaphase PtK1 cells are cooled to 6-8 degrees C for 4-6 h the free, polar, and astral spindle microtubules (MTs) disassemble while the MTs of each kinetochore fiber cluster together and persist as bundles of cold-stable MTs. These cold-stable kinetochore fibers are similar to untreated kinetochore fibers in both their length (i.e., 5-6 micrometer) and in the number of kinetochore-associated MTs (i.e., 20-45) of which they are comprised. Quantitative information concerning the lengths of MTs within these fibers was obtained by tracking individual MTs between serial transverse sections. Approximately 1/2 of the kinetochore MTs in each fiber were found to run uninterrupted into the polar region of the spindle. It can be inferred from this and other data that a substantial number of MTs run uninterrupted between the kinetochore and the polar region in untreated metaphase PtK1 cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cold Temperature*
  • Kidney
  • Marsupialia
  • Metaphase*
  • Microscopy, Electron
  • Microtubules / ultrastructure*