MyoD1 promoter autoregulation is mediated by two proximal E-boxes

Jean marc Zingg, Gustavo Pedraza-alva, Jean pierre Jost

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

We show that in mouse myoblasts the MyoD1 promoter is highly stimulated by MyoD1 expression, suggesting that it is controlled by a positive feedback loop. Using deletion and mutation analyses, we identified the targets for MyoD1 promoter autoregulation as the two proximal E-boxes located close to the MyoD1 core promoter. Gel mobility shift competition assays with MyoD1 antibodies as competitor suggest that the MyoD1 protein is binding directly to these E-boxes. Autoregulation did not occur in fibroblasts cotransfected with the expression vector of MyoD1. It is assumed that autoregulation is controlled by the stoichiometry between the MyoD1 protein and negatively regulatory proteins like Id, which is known to be highly expressed in fibroblasts. When the MyoD1 promoter was methylated, autoregulation only occurred when the density of methylated sites was low. The density of DNA methylation, therefore, can determine the accessibility of the MyoD1 promoter to transcription factors and interfere with the auto- and crossregulatory loop. The MyoD1 promoter in vivo was found to be only partially methylated in all tissues tested except in skeletal muscle where it was demethylated. We propose that high level expression of the MyoD1 gene is a result of release from constraints such as negative regulatory factors and/or DNA methylation interfering with MyoD1 autoregulation.

Original languageEnglish (US)
Pages (from-to)2234-2241
Number of pages8
JournalNucleic acids research
Volume22
Issue number12
DOIs
StatePublished - Jun 25 1994
Externally publishedYes

ASJC Scopus subject areas

  • Genetics

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