The DMPK gene of severely affected myotonic dystrophy patients is hypermethylated proximal to the largely expanded CTG repeat

Am J Hum Genet. 1998 Feb;62(2):278-85. doi: 10.1086/301711.

Abstract

Using methylation-sensitive restriction enzymes, we characterized the methylation pattern on the 5' side of the CTG repeat in the DMPK gene of normal individuals and of patients affected with myotonic dystrophy, showing expansions of the repetitive sequence. The gene segment analyzed corresponds to the genomic SacI-HindIII fragment carrying exons 11-15. There is constitutive methylation in intron 12 at restriction sites of SacII and HhaI, localized 1,159-1,232 bp upstream of the CTG repeat, whereas most, if not all, of the other sites of SacII, HhaI, and HpaII in this region are unmethylated, in normal individuals and most of the patients. In a number of young and severely affected patients, however, complete methylation of these restriction sites was found in the mutated allele. In most of these patients, the onset of the disease was congenital. Preliminary in vivo footprinting data gave evidence for protein-DNA contact in normal genes at an Sp1 consensus binding site upstream of the CTG repeat and for a significant reduction of this interaction in cells with a hypermethylated DMPK gene.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Base Sequence
  • Cells, Cultured
  • Child
  • DNA / chemistry
  • DNA / genetics
  • DNA Footprinting
  • DNA Methylation*
  • Dura Mater / embryology
  • Dura Mater / metabolism
  • Dura Mater / pathology
  • Fetus
  • Genomic Imprinting
  • Humans
  • Middle Aged
  • Myotonic Dystrophy / embryology
  • Myotonic Dystrophy / genetics*
  • Myotonin-Protein Kinase
  • Protein-Serine-Threonine Kinases / genetics*
  • Reference Values
  • Restriction Mapping
  • Trinucleotide Repeats*

Substances

  • DMPK protein, human
  • DNA
  • Myotonin-Protein Kinase
  • Protein-Serine-Threonine Kinases