mef2 activity levels differentially affect gene expression during Drosophila muscle development

The conserved Mef2 transcription factor is a major regulator of gene expression and differentiation. Recent genomic studies have identified a large number of mef2-regulated target genes with distinct temporal expression profiles during Drosophila myogenesis. However, the question remains as to how a single transcription factor can control such diverse patterns of gene expression. The aim of this project was to investigate whether there are genes with different mef2-requirements for their expression during muscle differentiation in vivo during the development of Drosophila melanogaster. Keywords: allelic series comparison We used microarrays in conjunction with a mef2 allelic series to determine the gene expression profile in developing embryos at five different levels of mef2 activity. The allelic series extends from a null mutation, mef222.21, through to the control, via three hypomorphic alleles, mef2113, mef2424, and mef265. The series corresponds to different levels of Mef2 in the following order: control > 65 > 424 > 113 > 22.21. The control stock for the microarray analysis was dp cn a px sp, the stock used for the mutagenesis that produced mef265, mef2424 and mef2113. For the microarrays, 30 minute collections of control and mutant embryos for each mef2 allele were individually staged and pools of 150 embryos were then processed at mid stage 13. This corresponds to the early differentiation phase of muscle development and the expression of multiple muscle sarcomeric protein genes. Quadruplicate samples were assayed using Affymetrix® Genechips by the Flychip Drosophila microarray resource.