Molecular analysis of the Arabidopsis pattern formation of gene GNOM: gene structure and intragenic complementation

Mol Gen Genet. 1996 Apr 10;250(6):681-91. doi: 10.1007/BF02172979.


The GNOM gene is required for pattern formation along the main body axis of the embryo in the flowering plant Arabidopsis thaliana. Mutations in the GNOM gene alter the asymmetric division of the zygote and interfere with the formation of distinct apical-basal regions in the developing embryo. We have isolated the GNOM gene by positional cloning, characterised its structure and determined the molecular lesions in mutant alleles. Although the predicted 163 kDa GNOM protein has a conserved domain in common with the yeast secretory protein Sec7p, it is most closely related in size and overall similarity to the product of the yeast YEC2 gene, which is not essential for cell viability. Four fully complementing gnom alleles carry missense mutations in conserved regions, seven partially complementing alleles have premature stop codon mutations and two non-complementing alleles have splice-site lesions. Our results suggest that the GNOM protein acts as a complex of identical subunits and that partial complementation may involve low levels of full-length protein generated by inefficient translational read-through.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Amino Acid Sequence
  • Arabidopsis / chemistry
  • Arabidopsis / embryology
  • Arabidopsis / genetics*
  • Arabidopsis Proteins*
  • Base Sequence
  • Cell Division / genetics
  • Chromosome Mapping
  • Cloning, Molecular
  • Codon, Terminator / genetics
  • Conserved Sequence / genetics
  • DNA Primers
  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism
  • Gene Expression Regulation, Developmental / genetics
  • Genes, Plant*
  • Genetic Complementation Test
  • Guanine Nucleotide Exchange Factors*
  • Molecular Sequence Data
  • Mutation / genetics
  • Plant Growth Regulators*
  • Plant Proteins / chemistry
  • Plant Proteins / genetics*
  • Sequence Analysis


  • Arabidopsis Proteins
  • Codon, Terminator
  • DNA Primers
  • Fungal Proteins
  • GNOM protein, Arabidopsis
  • Guanine Nucleotide Exchange Factors
  • Plant Growth Regulators
  • Plant Proteins