The maize genome contains a helitron insertion

Plant Cell. 2003 Feb;15(2):381-91. doi: 10.1105/tpc.008375.


The maize mutation sh2-7527 was isolated in a conventional maize breeding program in the 1970s. Although the mutant contains foreign sequences within the gene, the mutation is not attributable to an interchromosomal exchange or to a chromosomal inversion. Hence, the mutation was caused by an insertion. Sequences at the two Sh2 borders have not been scrambled or mutated, suggesting that the insertion is not caused by a catastrophic reshuffling of the maize genome. The insertion is large, at least 12 kb, and is highly repetitive in maize. As judged by hybridization, sorghum contains only one or a few copies of the element, whereas no hybridization was seen to the Arabidopsis genome. The insertion acts from a distance to alter the splicing of the sh2 pre-mRNA. Three distinct intron-bearing maize genes were found in the insertion. Of most significance, the insertion bears striking similarity to the recently described DNA helicase-bearing transposable elements termed HELITRONS: Like Helitrons, the inserted sequence of sh2-7527 is large, lacks terminal repeats, does not duplicate host sequences, and was inserted between a host dinucleotide AT. Like Helitrons, the maize element contains 5' TC and 3' CTRR termini as well as two short palindromic sequences near the 3' terminus that potentially can form a 20-bp hairpin. Although the maize element lacks sequence information for a DNA helicase, it does contain four exons with similarity to a plant DEAD box RNA helicase. A second Helitron insertion was found in the maize genomic database. These data strongly suggest an active Helitron in the present-day maize genome.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alternative Splicing
  • Amino Acid Sequence
  • Arabidopsis / genetics
  • Base Sequence
  • DNA Transposable Elements / genetics*
  • Genome, Plant*
  • Glucose-1-Phosphate Adenylyltransferase
  • Hybridization, Genetic
  • Introns
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Mutation
  • Nucleotidyltransferases / genetics
  • Nucleotidyltransferases / metabolism
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Poaceae / genetics
  • Seeds / genetics
  • Seeds / growth & development
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Sequence Homology, Nucleic Acid
  • Starch / biosynthesis
  • Sucrose / metabolism
  • Zea mays / genetics*
  • Zea mays / growth & development


  • DNA Transposable Elements
  • Plant Proteins
  • Sh2 protein, plant
  • Sucrose
  • Starch
  • Nucleotidyltransferases
  • Glucose-1-Phosphate Adenylyltransferase

Associated data

  • GENBANK/AF162682
  • GENBANK/AF293457
  • GENBANK/AF293458