DNA methylation inhibits expression and transposition of the Neurospora Tad retrotransposon

Mol Genet Genomics. 2001 Jun;265(4):748-54. doi: 10.1007/s004380100472.


Tad is a LINE-like retrotransposon of the filamentous fungus Neurospora crassa. We have analyzed both expression and transposition of this element using strains with a single copy of Tad located in the 5' noncoding sequences of the am (glutamate dehydrogenase) gene. Tad in this position has been shown to carry a de novo cytosine methylation signal which causes reversible methylation of both Tad and am upstream sequences. Here we find that methylation of the Tad sequences inhibits both Tad expression and transposition. This inhibition can be relieved by the use of 5-azacytidine, a drug which reduces cytosine methylation, or by placing the Tad/am sequences in a dim-2 genetic background.

Publication types

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

MeSH terms

  • Azacitidine / pharmacology
  • DNA Methylation* / drug effects
  • DNA, Fungal / genetics*
  • Escherichia coli / genetics
  • Gene Expression Regulation, Fungal* / drug effects
  • Gene Silencing* / drug effects
  • Genes, Reporter
  • Lac Operon
  • Neurospora crassa / genetics*
  • Recombinant Fusion Proteins / biosynthesis
  • Retroelements / genetics*


  • DNA, Fungal
  • Recombinant Fusion Proteins
  • Retroelements
  • Azacitidine