MOR1/GEM1 has an essential role in the plant-specific cytokinetic phragmoplast

Nat Cell Biol. 2002 Sep;4(9):711-4. doi: 10.1038/ncb844.


MOR1 is a member of the MAP215 family of microtubule-associated proteins and is required to establish interphase arrays of cortical microtubules in plant cells. Here we show that MOR1 binds microtubules in vivo, localizing to both cortical microtubules and to areas of overlapping microtubules in the phragmoplast. Genetic complementation of the cytokinesis-defective gemini pollen 1-1 (gem1-1) mutation with MOR1 shows that MOR1 (which is synonymous with the protein GEM1) is essential in cytokinesis. Phenotypic analysis of gem1-1 and gem1-2, which contains a T-DNA insertion, confirm that MOR1/GEM1 is essential for regular patterns of cytokinesis. Both the gem1-1 and gem1-2 mutations cause the truncation of the MOR1/GEM1 protein. In addition, the carboxy-terminal domain of the protein, which is absent in both mutants, binds microtubules in vitro. Our data show that MOR1/GEM1 has an essential role in the cytokinetic phragmoplast.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Arabidopsis / cytology
  • Arabidopsis / genetics
  • Arabidopsis / physiology
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / physiology*
  • Base Sequence
  • Brain / metabolism
  • Cell Division / physiology*
  • DNA, Plant / genetics
  • Genes, Plant
  • Genetic Complementation Test
  • In Vitro Techniques
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / physiology*
  • Microtubules / metabolism
  • Molecular Sequence Data
  • Mutation
  • Phenotype
  • Plant Proteins / genetics
  • Plant Proteins / physiology*
  • Swine


  • Arabidopsis Proteins
  • DNA, Plant
  • MOR1 protein, Arabidopsis
  • Microtubule-Associated Proteins
  • Plant Proteins

Associated data

  • GENBANK/AY124770