Promoters are DNA sequences located upstream of genes, and their sequence composition influences their binding affinity with RNA polymerase, which determines the transcription rate. I aim to elucidate the sequence-function relationship of bacterial promoter elements, with particular interest on the upstream (UP) region and discriminator (Dis). The quantitative impact of both elements on promoter strength is poorly understood. I apply saturated mutagenesis and massively parallel reporter assays to characterize UP and Dis at high degree of resolution. I have successfully conducted a high-throughput characterization of the Dis element. Preliminary analysis shows that GC is more enriched in weaker variants while for stronger variants AT is more enriched. I have also performed in silico analyses on various bacterial species, such as Escherichia coli, and found that the same rules apply to most genes. This indicates that Dis element is optimized for high expression in E coli genes. The insights gained from these experiments can be used to construct an in silico model for predicting and designing promoter functions
Mapping the sequence function relationship of UP and Dis promoter elements in bacteria promoters