Partial characterization of the mouse alpha-sarcoglycan promoter and its responsiveness to MyoD.
The mouse alpha-sarcoglycan gene is expressed in muscle cells during differentiation, but its transcriptional regulation is not understood. We have characterized the promoter region of the mouse alpha-sarcoglycan gene. This region is composed of positive and negative regulatory elements that respond to the myogenic differentiation environment. Accordingly, MyoD transactivates the alpha-sarcoglycan full-length and the proximal promoter. Chromatin immunoprecipitation assays revealed that MyoD, TFIID, and TFIIB interact with the distal promoter in C2C12 myoblasts, a stage at which the alpha-SG promoter appears to drive basal activity. In myotubes, such factors are located concomitantly at the distal promoter and at a DNA region around the proximal promoter. In agreement with these results, TFIID and TFIIB co-immunoprecipitate with MyoD. We conclude that the alpha-SG promoter is activated by MyoD, which interacts with TFIID and TFIIB in a protein complex differentially located at the distal promoter and around the proximal promoter during myogenic cell differentiation.
Delgado-Olguín
Paul
P
Unidad de Investigación Médica en Genética Humana, Hospital de Pediatría, Centro Médico Nacional Siglo XXI (CMN-SXXI), Instituto Mexicano del Seguro Social (IMSS), Mexico City, Mexico.
Recillas-Targa
Félix
F
Rosas-Vargas
Haydeé
H
Salamanca
Fabio
F
Coral-Vázquez
Ramón M
RM
D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D005786:Gene Expression Regulation; D051379:Mice; D008969:Molecular Sequence Data; D024510:Muscle Development / Q000235:genetics*; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D017570:MyoD Protein / Q000378:metabolism*; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism; D011401:Promoter Regions, Genetic; D049031:Sarcoglycans / Q000235:genetics*; D035581:Transcription Factor TFIIB / Q000378:metabolism; D035362:Transcription Factor TFIID / Q000378:metabolism; D015533:Transcriptional Activation
D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D049031:Sarcoglycans; D035581:Transcription Factor TFIIB; D035362:Transcription Factor TFIID