A novel muscle-specific enhancer identified within the deletion overlap region of two XLDC patients lacking muscle exon 1 of the human dystrophin gene.
Previous studies point to the involvement of several discrete transcriptional enhancers in the modulation of dystrophin gene expression in skeletal and cardiac muscle. Analysis of deletion breakpoints in two X-linked dilated cardiomyopathy patients with mutations that remove muscle exon 1 identified a 3.2-kb deletion overlap region (XLDC3.2) between -1199 and +2057 bp predicted to contain regulatory elements essential for dystrophin gene expression in cardiac muscle. A novel-sequence-based search strategy was used to identify a 543-bp region downstream of muscle exon 1 rich in cardiac-specific transcriptional elements. Designated dystrophin muscle enhancer 2 (DME2), this candidate enhancer was seen to function in a position- and orientation-independent manner in muscle cell lines but not in fibroblasts. As only modest activity was observed in primary neonatal rat cardiomyocytes, DME2 is thought to play a role in dystrophin gene regulation at later stages of cardiac muscle development.
Bastianutto
Carlo
C
Ontario Cancer Institute, Princess Margaret Hospital, Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, Ontario, M5G 2M9, Canada.
De Visser
Marianne
M
Muntoni
Francesco
F
Klamut
Henry J
HJ
Patarnello
Tomaso
T
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D002311:Cardiomyopathy, Dilated / Q000235:genetics*; D002460:Cell Line; D016189:Dystrophin / Q000235:genetics*; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D005091:Exons / Q000235:genetics*; D008040:Genetic Linkage; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D014162:Transfection; D014960:X Chromosome / Q000235:genetics*; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D016189:Dystrophin; D011993:Recombinant Fusion Proteins; D008156:Luciferases; D001616:beta-Galactosidase