DUX4c is up-regulated in FSHD. It induces the MYF5 protein and human myoblast proliferation.
Facioscapulohumeral muscular dystrophy (FSHD) is a dominant disease linked to contractions of the D4Z4 repeat array in 4q35. We have previously identified a double homeobox gene (DUX4) within each D4Z4 unit that encodes a transcription factor expressed in FSHD but not control myoblasts. DUX4 and its target genes contribute to the global dysregulation of gene expression observed in FSHD. We have now characterized the homologous DUX4c gene mapped 42 kb centromeric of the D4Z4 repeat array. It encodes a 47-kDa protein with a double homeodomain identical to DUX4 but divergent in the carboxyl-terminal region. DUX4c was detected in primary myoblast extracts by Western blot with a specific antiserum, and was induced upon differentiation. The protein was increased about 2-fold in FSHD versus control myotubes but reached 2-10-fold induction in FSHD muscle biopsies. We have shown by Western blot and by a DNA-binding assay that DUX4c over-expression induced the MYF5 myogenic regulator and its DNA-binding activity. DUX4c might stabilize the MYF5 protein as we detected their interaction by co-immunoprecipitation. In keeping with the known role of Myf5 in myoblast accumulation during mouse muscle regeneration DUX4c over-expression activated proliferation of human primary myoblasts and inhibited their differentiation. Altogether, these results suggested that DUX4c could be involved in muscle regeneration and that changes in its expression could contribute to the FSHD pathology.
Ansseau
Eugénie
E
Laboratory of Molecular Biology, University of Mons-Hainaut, 6, Mons, Belgium.
Laoudj-Chenivesse
Dalila
D
Marcowycz
Aline
A
Tassin
Alexandra
A
Vanderplanck
Céline
C
Sauvage
Sébastien
S
Barro
Marietta
M
Mahieu
Isabelle
I
Leroy
Axelle
A
Leclercq
India
I
Mainfroid
Véronique
V
Figlewicz
Denise
D
Mouly
Vincent
V
Butler-Browne
Gillian
G
Belayew
Alexandra
A
Coppée
Frédérique
F
D000818:Animals; D001706:Biopsy; D049109:Cell Proliferation; D005786:Gene Expression Regulation; D006367:HeLa Cells; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics*; D006801:Humans; D051379:Mice; D008957:Models, Genetic; D009132:Muscles / Q000473:pathology; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000235:genetics* / Q000473:pathology; D032446:Myoblasts / Q000166:cytology*; D051787:Myogenic Regulatory Factor 5 / Q000096:biosynthesis* / Q000235:genetics*; D017434:Protein Structure, Tertiary; D015854:Up-Regulation
C121257:DUX4L1 protein, human; D018398:Homeodomain Proteins; C497417:MYF5 protein, human; D051787:Myogenic Regulatory Factor 5