A homologue of the yeast HOP1 gene is inactivated in the Arabidopsis meiotic mutant asy1

Chromosoma. 2000;109(1-2):62-71. doi: 10.1007/s004120050413.


Synapsis of homologous chromosomes is a key event in meiosis as it is essential for normal chromosome segregation and is implicated in the regulation of crossover frequency. We have previously reported the identification and cytological characterisation of a T-DNA-tagged asynaptic mutant of Arabidopsis thaliana. We have demonstrated that this mutant, asy1, is defective in meiosis in both males and females. Cloning and nucleotide sequencing of the ASY1 gene has revealed that it encodes a polypeptide of 596 amino acids that exhibits similarity to the HOP1 gene of Saccharomyces cerevisiae, which is known to encode a protein essential for synaptonemal complex assembly and normal synapsis. Expression studies indicate that, in common with a number of other Arabidopsis meiotic genes, ASY1 exhibits low-level expression in a range of plant tissues. Southern analysis coupled with database searching has resulted in the identification of an ASY1 homologue, ASY2. Although asy1 exhibits a strong asynaptic phenotype, a residual low level of synapsis indicates that ASY1 and ASY2 may exhibit a low degree of functional redundancy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis Proteins*
  • Base Sequence
  • Blotting, Southern
  • Chromosome Segregation / genetics
  • Cloning, Molecular
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics*
  • Fungal Proteins / genetics*
  • Meiosis / genetics*
  • Molecular Sequence Data
  • Plant Proteins / biosynthesis
  • Plant Proteins / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins*
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Synaptonemal Complex / genetics


  • ASY1 protein, Arabidopsis
  • ASY2 protein, Arabidopsis
  • Arabidopsis Proteins
  • DNA-Binding Proteins
  • Fungal Proteins
  • HOP1 protein, S cerevisiae
  • Plant Proteins
  • Saccharomyces cerevisiae Proteins

Associated data

  • GENBANK/AF157556