Influence of transposable elements on the structure and function of the A1 gene of Zea mays

EMBO J. 1987 Feb;6(2):287-94.


The structure of the A1 gene of Zea mays was determined by sequencing cDNA and genomic clones. The gene is composed of four exons and three short introns. The 40.1-kd A1 protein is an NADPH-dependent reductase. Germinal derivatives of the mutable a1-m1 allele with either recessive or wild-type phenotype have been isolated. Sequence analysis of these revertant alleles indicates that frame-shift mutations abolish A1 gene function, whereas one additional amino acid within the protein sequence still allows wild-type gene expression. The presence of a second, promoter-like structure, upstream of the functional A1 gene promoter is discussed with respect to its possible involvement in differential expression of the A1 gene. The structure of the a1-m2 8004, 3456 and 4412 alleles, featuring distinguishable phenotypes in the presence of Spm(En), was also determined. In all alleles the 1080-bp-long inhibitor (I) element is located 15 bp upstream of the CAAT box of the A1 gene promoter. The unusual response of a1-m2 alleles to trans-active signals of the Spm(En) element is discussed with respect to the position of the I inserts. Also presented are data on the structure and insertion sites of transposable elements determined by cloning and sequencing of the mutable a1 alleles a1-mpapu, a1-mr 102 and a1-ml.

MeSH terms

  • Alcohol Oxidoreductases / genetics*
  • Alleles
  • Base Sequence
  • DNA Transposable Elements / genetics*
  • Genes, Plant / genetics*
  • Molecular Sequence Data
  • Phenotype
  • Plant Proteins / genetics*
  • Zea mays / genetics*


  • DNA Transposable Elements
  • Plant Proteins
  • Alcohol Oxidoreductases
  • A1 protein, Zea mays