The suppressor-mutator element and the evolutionary riddle of transposons

Genes Cells. 1999 Jan;4(1):11-9. doi: 10.1046/j.1365-2443.1999.00233.x.


This review focuses on the epigenetic control of the maize Suppressor-mutator (Spm) transposon and the evolutionary origin of epigenetic mechanisms. Methylation of the Spm promoter prevents transcription and transposition, and the methylation of the adjacent GC-rich sequence renders the inactive state heritable. Spm encodes an epigenetic activator, TnpA, one of the two Spm-encoded transposition proteins. TnpA can reactivate an inactive, methylated Spm both transiently and heritably, and it is also a transcriptional repressor of the unmethylated Spm promoter. Features common to epigenetic mechanisms in general suggest that they originated as a means of decreasing the recombinogenicity of duplicated sequences.

Publication types

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

MeSH terms

  • DNA Transposable Elements / genetics*
  • DNA-Binding Proteins / genetics
  • Evolution, Molecular*
  • Gene Duplication
  • Gene Expression Regulation
  • Methylation
  • Models, Genetic
  • Plant Proteins*
  • Plants, Genetically Modified
  • Repressor Proteins / genetics
  • Suppression, Genetic / genetics*


  • DNA Transposable Elements
  • DNA-Binding Proteins
  • Plant Proteins
  • Repressor Proteins