Chromosome congression in the absence of kinetochore fibres

Nat Cell Biol. 2009 Jul;11(7):832-8. doi: 10.1038/ncb1890. Epub 2009 Jun 14.

Abstract

Proper chromosome congression (the process of aligning chromosomes on the spindle) contributes to accurate and faithful chromosome segregation. It is widely accepted that congression requires kinetochore fibres (K-fibres), microtubule bundles that extend from the kinetochores to spindle poles. Here, we demonstrate that chromosomes in human cells co-depleted of HSET (human kinesin-14) and hNuf2 (human Ndc80/Hec1-complex component) can congress to the metaphase plate in the absence of K-fibres. However, the chromosomes are not stably maintained at the metaphase plate under these conditions. Chromosome congression in HSET + hNuf2 co-depleted cells required the plus-end directed motor CENP-E (centromere protein E; kinesin-7 family member), which has been implicated in the gliding of mono-oriented kinetochores alongside adjacent K-fibres. Thus, proper end-on attachment of kinetochores to microtubules is not necessary for chromosome congression. Instead, our data support the idea that congression allows unattached chromosomes to move to the middle of the spindle where they have a higher probability of establishing connections with both spindle poles. These bi-oriented connections are also used to maintain stable chromosome alignment at the spindle equator.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cell Cycle Proteins / physiology
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / metabolism
  • Chromosomal Proteins, Non-Histone / physiology
  • Chromosome Segregation / genetics
  • Chromosome Segregation / physiology
  • Chromosomes / genetics
  • Chromosomes / metabolism*
  • Fluorescent Antibody Technique
  • HeLa Cells
  • Humans
  • Kinesin / genetics
  • Kinesin / metabolism
  • Kinesin / physiology
  • Kinetochores / metabolism*
  • Metaphase / genetics
  • Prometaphase / genetics
  • Spindle Apparatus / metabolism

Substances

  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone
  • KIFC1 protein, human
  • NUF2 protein, human
  • centromere protein E
  • Kinesin