RNA accumulation of the CCUG repeat in DM2 muscle. (A) Genomic organization of the ZNF9 gene. The DM2 expansion is located in an intron or a portion of the ZNF9 gene that is made into an intermediate RNA molecule but that is removed before protein synthesis. (B) RNA foci (pink) containing the CCUG expansion accumulate in the cell's nuclei (blue) in muscle tissue from DM2 patients (C) control showing that CCUG foci are not detected in normal muscle. (D) RNA foci (pink) showing CUG expansion in DM1 muscle . The scale bar is 5 mM. Research by Laura Ranum and John W. Day, Institute of Human Genetics, University of Minnesota. Figure Copyright Science (American Association for the Advancement of Science).