Effect of the [CCTG]n repeat expansion on ZNF9 expression in myotonic dystrophy type II (DM2)

Biochim Biophys Acta. 2006 Mar;1762(3):329-34. doi: 10.1016/j.bbadis.2005.11.004. Epub 2005 Dec 6.


Myotonic dystrophy is caused by two different mutations: a (CTG)n expansion in 3' UTR region of the DMPK gene (DM1) and a (CCTG)n expansion in intron 1 of the ZNF9 gene (DM2). The most accredited mechanism for DM pathogenesis is an RNA gain-of-function. Other findings suggest a contributory role of DMPK-insufficiency in DM1. To address the issue of ZNF9 role in DM2, we have analyzed the effects of (CCTG)n expansion on ZNF9 expression in lymphoblastoid cell lines (n=4) from DM2 patients. We did not observe any significant alteration in ZNF9 mRNA and protein levels, as shown by QRT-PCR and Western blot analyses. Additional RT-PCR experiments demonstrated that ZNF9 pre-mRNA splicing pattern, which includes two isoforms, is unmodified in DM2 cells. Our results indicate that the (CCTG)n expansion in the ZNF9 intron does not appear to have a direct consequence on the expression of the gene itself.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence*
  • Cells, Cultured
  • DNA Repeat Expansion*
  • Gene Expression Regulation*
  • Humans
  • In Situ Hybridization, Fluorescence
  • Introns
  • Lymphocytes / cytology
  • Lymphocytes / physiology
  • Molecular Sequence Data
  • Mutation
  • Myotonic Dystrophy / genetics*
  • Myotonic Dystrophy / metabolism
  • Phenotype
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • RNA Precursors / metabolism
  • RNA Splicing
  • RNA-Binding Proteins* / genetics
  • RNA-Binding Proteins* / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Zinc Fingers


  • CNBP protein, human
  • Protein Isoforms
  • RNA Precursors
  • RNA-Binding Proteins
  • Recombinant Fusion Proteins