Reactivation of Mutator transposable elements of maize by ultraviolet light

Mol Gen Genet. 1992 Sep;234(3):353-60. doi: 10.1007/BF00538694.


After epigenetic loss of Mutator activity, the family of Mu elements in Zea mays becomes immobile and highly methylated; in addition, Mu9, the presumptive autonomous regulatory element, is transcriptionally silent and its copy number decreases in successive crosses to non-Mutator lines. Spontaneous reactivation, scored as restoration of somatic instability of potentially mutable alleles of Bronze-2, of such cryptic Mutator lines is rare, occurring with a frequency of about 10(-4). Irradiation of pollen with 254 nm ultraviolet light increases reactivation rate in the progeny kernels by up to 40-fold. Accompanying reactivation, the copy number of Mu9 elements increased, two-fold in one line and 20 to 40-fold in a second line. Reactivation may involve direct DNA damage or immediate physiological stress in the treated pollen.

Publication types

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

MeSH terms

  • DNA / metabolism
  • DNA / radiation effects
  • DNA Transposable Elements / radiation effects*
  • Methylation
  • Mutation*
  • Pollen / radiation effects
  • Ultraviolet Rays
  • Zea mays / genetics*


  • DNA Transposable Elements
  • DNA