TY - JOUR
T1 - An isogenetic myoblast expression screen identifies DUX4-mediated FSHD-associated molecular pathologies
AU - Bosnakovski, Darko
AU - Xu, Zhaohui
AU - Ji Gang, Eun
AU - Galindo, Cristi L.
AU - Liu, Mingju
AU - Simsek, Tugba
AU - Garner, Harold R.
AU - Agha-Mohammadi, Siamak
AU - Tassin, Alexandra
AU - Coppée, Frédérique
AU - Belayew, Alexandra
AU - Perlingeiro, Rita R.
AU - Kyba, Michael
PY - 2008/10/22
Y1 - 2008/10/22
N2 - Facioscapulohumeral muscular dystrophy (FSHD) is caused by an unusual deletion with neomorphic activity. This deletion derepresses genes in cis; however which candidate gene causes the FSHD phenotype, and through what mechanism, is unknown. We describe a novel genetic tool, inducible cassette exchange, enabling rapid generation of isogenetically modified cells with conditional and variable transgene expression. We compare the effects of expressing variable levels of each FSHD candidate gene on myoblasts. This screen identified only one gene with overt toxicity: DUX4 (double homeobox, chromosome 4), a protein with two homeodomains, each similar in sequence to Pax3 and Pax7. DUX4 expression recapitulates key features of the FSHD molecular phenotype, including repression of MyoD and its target genes, diminished myogenic differentiation, repression of glutathione redox pathway components, and sensitivity to oxidative stress. We further demonstrate competition between DUX4 and Pax3/Pax7: when either Pax3 or Pax7 is expressed at high levels, DUX4 is no longer toxic. We propose a hypothesis for FSHD in which DUX4 expression interferes with Pax7 in satellite cells, and inappropriately regulates Pax targets, including myogenic regulatory factors, during regeneration.
AB - Facioscapulohumeral muscular dystrophy (FSHD) is caused by an unusual deletion with neomorphic activity. This deletion derepresses genes in cis; however which candidate gene causes the FSHD phenotype, and through what mechanism, is unknown. We describe a novel genetic tool, inducible cassette exchange, enabling rapid generation of isogenetically modified cells with conditional and variable transgene expression. We compare the effects of expressing variable levels of each FSHD candidate gene on myoblasts. This screen identified only one gene with overt toxicity: DUX4 (double homeobox, chromosome 4), a protein with two homeodomains, each similar in sequence to Pax3 and Pax7. DUX4 expression recapitulates key features of the FSHD molecular phenotype, including repression of MyoD and its target genes, diminished myogenic differentiation, repression of glutathione redox pathway components, and sensitivity to oxidative stress. We further demonstrate competition between DUX4 and Pax3/Pax7: when either Pax3 or Pax7 is expressed at high levels, DUX4 is no longer toxic. We propose a hypothesis for FSHD in which DUX4 expression interferes with Pax7 in satellite cells, and inappropriately regulates Pax targets, including myogenic regulatory factors, during regeneration.
KW - Cassette exchange
KW - DUX4
KW - Facioscapulohumeral muscular dystrophy
KW - Myoblast
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UR - http://www.scopus.com/inward/citedby.url?scp=54349088194&partnerID=8YFLogxK
U2 - 10.1038/emboj.2008.201
DO - 10.1038/emboj.2008.201
M3 - Article
C2 - 18833193
AN - SCOPUS:54349088194
SN - 0261-4189
VL - 27
SP - 2766
EP - 2779
JO - EMBO Journal
JF - EMBO Journal
IS - 20
ER -