Fig. 2. Deletion analysis of the ecmO region. (A) Structure of the minimal ecmO region and expression patterns for two deletion mutants. The structure of the minimal 94 nucleotide ecmO promoter region (see Fig. 1) and of two 5'-3' deletion mutants is shown. The STATa-binding site is underlined, as are the MybE dyad and the adjacent C-rich region. These three promoter fragments were cloned upstream of basal promoter elements in a lacZ reporter construct and their spatial expression patterns determined at the indicated stages of development. (B) Analysis of DIF inducibility of the 94-mer and the two deletion mutants. Transformants of the three constructs analysed in A were rendered DIF-competent and either induced or not induced with DIF. The lacZ expression level is presented without normalisation, so that absolute expression levels can be compared between the three constructs.