CUL-2 and ZYG-11 promote meiotic anaphase II and the proper placement of the anterior-posterior axis in C. elegans

Development. 2004 Aug;131(15):3513-25. doi: 10.1242/dev.01245. Epub 2004 Jun 23.

Abstract

The faithful segregation of chromosomes during meiosis is vital for sexual reproduction. Currently, little is known about the molecular mechanisms regulating the initiation and completion of meiotic anaphase. We show that inactivation of CUL-2, a member of the cullin family of ubiquitin ligases, delays or abolishes meiotic anaphase II with no effect on anaphase I, indicating differential regulation during the two meiotic stages. In cul-2 mutants, the cohesin REC-8 is removed from chromosomes normally during meiosis II and sister chromatids separate, suggesting that the failure to complete anaphase results from a defect in chromosome movement rather than from a failure to sever chromosome attachments. CUL-2 is required for the degradation of cyclin B1 in meiosis and inactivation of cyclin B1 partially rescued the meiotic delay in cul-2 mutants. In cul-2 mutants, the failure to degrade cyclin B1 precedes the metaphase II arrest. CUL-2 is also required for at least two aspects of embryonic polarity. The extended meiosis II in cul-2 mutants induces polarity reversals that include reversed orientation of polarity proteins, P granules, pronuclei migration and asymmetric cell division. Independently of its role in meiotic progression, CUL-2 is required to limit the initiation/spread of the polarity protein PAR-2 in regions distant from microtubule organizing centers. Finally, we show that inactivation of the leucine-rich repeat protein ZYG-11 produces meiotic and polarity reversal defects similar to those observed in cul-2 mutants, suggesting that the two proteins function in the same pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaphase
  • Animals
  • Body Patterning*
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Polarity
  • Chromatids
  • Chromosome Segregation*
  • Cullin Proteins / genetics
  • Cullin Proteins / metabolism*
  • Cyclin B / metabolism
  • Cyclin B1
  • Cytoskeleton / metabolism
  • Meiosis / physiology*
  • Morphogenesis
  • Nuclear Proteins / metabolism
  • RNA Interference
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism

Substances

  • Caenorhabditis elegans Proteins
  • Cell Cycle Proteins
  • Cullin Proteins
  • Cyclin B
  • Cyclin B1
  • Nuclear Proteins
  • Recombinant Fusion Proteins
  • cul-2 proteins, C elegans
  • par-2 protein, C elegans
  • zyg-11 protein, C elegans