Introduction of a DNA methyltransferase into Drosophila to probe chromatin structure in vivo

Chromosoma. 1996;104(5):332-40. doi: 10.1007/BF00337221.


The dam DNA methyltransferase gene from Escherichia coli was introduced into Drosophila in order to probe chromatin structure in vivo. Expression of the gene caused no visible defects or developmental delay even at high levels of active methylase. About half of each target site was found to be methylated in vivo, apparently reflecting a general property of chromatin packaged in nucleosomes. Although site-specific differences were detected, most euchromatic and heterochromatic sites showed comparable degrees of methylation, at least at high methylase levels. Methylase accessibility of a lacZ reporter gene subject to position-effect variegation throughout development was only slightly reduced, consistent with studies of chromatin accessibility in vitro. Silencing of lacZ during development differed from silencing of an adjacent white eye pigment reporter gene in the adult, as though chromatin structure can undergo dynamic alterations during development.

Publication types

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

MeSH terms

  • Animals
  • Base Sequence
  • Cell Extracts
  • Chromatin*
  • DNA / analysis
  • DNA / metabolism*
  • Drosophila melanogaster / cytology
  • Drosophila melanogaster / growth & development*
  • Escherichia coli / enzymology
  • Escherichia coli Proteins
  • Eye
  • Female
  • Gene Expression
  • Gene Transfer Techniques
  • Genes, Bacterial / genetics
  • Genes, Reporter / genetics
  • Male
  • Methylation
  • Molecular Sequence Data
  • Phenotype
  • Site-Specific DNA-Methyltransferase (Adenine-Specific)* / genetics
  • Site-Specific DNA-Methyltransferase (Adenine-Specific)* / metabolism
  • beta-Galactosidase / genetics


  • Cell Extracts
  • Chromatin
  • Escherichia coli Proteins
  • DNA
  • Dam methyltransferase
  • Site-Specific DNA-Methyltransferase (Adenine-Specific)
  • dam protein, E coli
  • beta-Galactosidase