Molecular and General Genetics MGG

, Volume 208, Issue 1–2, pp 57–62 | Cite as

Concomitant regulation of Mu1 transposition and Mutator activity in maize

  • J. L. Bennetzen
  • R. P. Fracasso
  • D. W. Morris
  • D. S. Robertson
  • M. J. Skogen-Hagenson


The mutagenic activity of the maize transposable element system Mutator can be lost by outcrossing to standard, non-Mutator lines or by repetitive intercrossing of genetically diverse Mutator lines. Lines losing Mutator mutagenic activity in either manner retain high copy numbers (10–15 per diploid genome) of the Mutator-associated Mu transposable elements. Frequent transposition of Mu1-related elements is observed only in active Mutator lines, however. The loss of Mutator activity on intercrossing is correlated with an increase in the copy number of Mu1-like elements to 40–50 per diploid genome, implying a self-encoded or self-activated negative regulator of Mu1 transposition. The outcross loss of Mutator activity is only weakly correlated with a low Mu element copy number and may be due to the loss of a positive regulatory factor encoded by a subset of Mu1-like elements. Transposition of Mu elements in active Mutator lines generates multiple new genomic positions for about half the elements each plant generation. The appearance of Mu1-like elements in these new positions is not accompanied by equally high germinal reversion frequencies, suggesting that Mu1 may commonly transpose via a DNA replicative process.

Key words

Transposable elements Mutation Mutator Maize 


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Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • J. L. Bennetzen
    • 1
  • R. P. Fracasso
    • 1
  • D. W. Morris
    • 2
  • D. S. Robertson
    • 2
  • M. J. Skogen-Hagenson
    • 2
  1. 1.Department of Biological SciencesPurdue UniversityWest LafayetteUSA
  2. 2.Department of GeneticsIowa State UniversityAmesUSA

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