Binding of TFIID and MEF2 to the TATA element activates transcription of the Xenopus MyoDa promoter.
Members of the MyoD family of helix-loop-helix proteins control expression of the muscle phenotype by regulating the activity of subordinate genes. To investigate processes that control the expression of myogenic factors and regulate the establishment and maintenance of the skeletal muscle phenotype, we have analyzed sequences necessary for transcription of the maternally expressed Xenopus MyoD (XMyoD) gene. A 3.5-kb DNA fragment containing the XMyoDa promoter was expressed in a somite-specific manner in injected frog embryos. The XMyoDa promoter was active in oocytes and cultured muscle cells but not in fibroblasts or nonmuscle cell lines. A 58-bp fragment containing the transcription initiation site, a GC-rich region, and overlapping binding sites for the general transcription factor TFIID and the muscle-specific factor MEF2 was sufficient for muscle-specific transcription. Transcription of the minimal XMyoDa promoter in nonmuscle cells was activated by expression of Xenopus MEF2 (XMEF2) and required binding of both MEF2 and TFIID to the TATA motif. These results demonstrate that the XMyoDa TATA motif is a target for a cell-type-specific regulatory factor and suggests that MEF2 stabilizes and amplifies XMyoDa transcription in mesodermal cells committed to the muscle phenotype.
Leibham
D
D
Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston 77030.
Wong
M W
MW
Cheng
T C
TC
Schroeder
S
S
Weil
P A
PA
Olson
E N
EN
Perry
M
M
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002454:Cell Differentiation; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D064326:MEF2 Transcription Factors; D008969:Molecular Sequence Data; D009132:Muscles / Q000166:cytology / Q000378:metabolism; D016296:Mutagenesis; D017570:MyoD Protein / Q000235:genetics*; D018006:Myogenic Regulatory Factors; D011401:Promoter Regions, Genetic; D012689:Sequence Homology, Nucleic Acid; D016385:TATA Box; D014018:Tissue Distribution; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation; D014982:Xenopus laevis / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; D064326:MEF2 Transcription Factors; D017570:MyoD Protein; D018006:Myogenic Regulatory Factors; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D004247:DNA