The mechanism of acentrosomal spindle assembly in human oocytes

Science. 2022 Nov 18;378(6621):eabq7361. doi: 10.1126/science.abq7361. Epub 2022 Nov 18.

Abstract

Meiotic spindle assembly ensures proper chromosome segregation in oocytes. However, the mechanisms behind spindle assembly in human oocytes remain largely unknown. We used three-dimensional high-resolution imaging of more than 2000 human oocytes to identify a structure that we named the human oocyte microtubule organizing center (huoMTOC). The proteins TACC3, CCP110, CKAP5, and DISC1 were found to be essential components of the huoMTOC. The huoMTOC arises beneath the oocyte cortex and migrates adjacent to the nuclear envelope before nuclear envelope breakdown (NEBD). After NEBD, the huoMTOC fragments and relocates on the kinetochores to initiate microtubule nucleation and spindle assembly. Disrupting the huoMTOC led to spindle assembly defects and oocyte maturation arrest. These results reveal a physiological mechanism of huoMTOC-regulated spindle assembly in human oocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Chromosome Segregation
  • Humans
  • Kinetochores / metabolism
  • Microtubule-Associated Proteins / metabolism
  • Microtubule-Organizing Center* / metabolism
  • Oocytes* / metabolism
  • Spindle Apparatus* / metabolism

Substances

  • Microtubule-Associated Proteins
  • TACC3 protein, human
  • CCP110 protein, human
  • CKAP5 protein, human
  • DISC1 protein, human