Transcriptional Regulation of Mef2 Expression in the Developing Mesoderm of Drosophila melanogaster

The mesoderm gives rise to and directs the differentiation of blood, fat body, and muscle cells. Proper development of the mesoderm is required for muscular differentiation and development.  Mef2 (Myocyte enhancer factor 2) is a transcription factor required for embryonic mesoderm development in Drosophila melanogaster. Various factors regulate Mef2 transcription at early and late stages in embryo development. The transcription factors Twist, Mad/Medea, and Dorsal are candidates for Mef2 regulation at the onset of its expression, and it is possible that these factors interact to impel Mef2 expression. Since the enhancer regulating early Mef2 expression has been identified, we can now determine how these transcription factors interact. To test our hypothesis, electrophoretic mobility shift assays will be conducted to examine the extent to which these factors bind the enhancer region. Next, constructs containing lacZ reporters carrying mutations in the transcription binding sites will be made. P-element transformations will be conducted with these constructs to examine how the transcription factors drive activity of the enhancer region in vivo. Mad-Medea has been shown to bind to the enhancer region (Nguyen and Xu 1998) and we have found that Twist also binds to the enhancer region. Binding of Dorsal is yet to be demonstrated. This study will characterize and further define how these transcription factors interact to initiate and regulate Mef2 expression. Due to the high conservation of these developmental mechanisms from D. melanogaster to humans, this study will be a useful model by which to understand the cellular mechanisms of development and disease.