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DUX4 transcriptionally regulates paired‐like homeodomain transcription factor 1
Author(s) -
Chen YiWen,
Dixit Manjusha,
Brown Aquanette,
Belayew Alexandra
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a182-b
Subject(s) - facioscapulohumeral muscular dystrophy , luciferase , transcription factor , homeobox , microbiology and biotechnology , myod , transfection , transcription (linguistics) , biology , chemistry , gene , genetics , linguistics , philosophy
Facioscapulohumeral muscular dystrophy (FSHD) is an inherited muscle disorder caused by a deletion of the 3.3 kb D4Z4 repeat array in the subtelomeric region of chromosome 4q35. The only known gene, double homeobox protein 4, in each of the repeat unit was shown up‐regulated in FSHD myoblasts. In this study, we determined whether paired‐like homeodomain transcription factor 1 (PITX1) which was shown specifically up‐regulated in FHSD was a direct transcriptional target of DUX4. A Pitx1 promoter fragment with a putative DUX4 binding site was inserted to the pGL3‐basic luciferase reporter vector. Co‐transfection of the vector with either pCIneo‐DUX4, pCIneo‐DUX4c or pCIneo‐DUX1 expression vector in C2C12 cells led to a 7.4‐fold increase (n=4, p=1.6x10‐21), 4.3‐fold increase (p=0.002) and no increase of the luciferase activity, respectively. Samples co‐transfected with insertless vector was used as controls. Site directed mutagenesis significantly decreased the luciferase activity in pCIneo‐DUX4 (p=1.7x10‐17) and pCIneo‐DUX4c (p=0.047), respectively. Electro‐mobility shift assay (EMSA) confirmed the specificity of the interaction. This is the first study identifying a direct transcription target of DUX4, which provides a direct link between the genetic defect in 4q35 and the downstream molecular changes specific to FSHD.