245A Poster - 02. Immunity and the microbiome
Thursday April 07, 2:00 PM - 4:00 PM

Authors:
Lianne Cohen; Zeba Wunderlich

Affiliation: Boston University, Boston MA

Keywords:
d. transcriptional regulation; e. enhancers

An organism’s ability to launch an appropriate and robust response to environmental stimuli is critical for its survival. Infection from a variety of microorganisms is a common and potentially lethal threat that host organisms combat by initiating an immune response. Much of this response is controlled by regulatory DNA, specifically promoters and enhancers. Enhancers are cis-regulatory sequences containing transcription factor binding sites (TFBS) that can direct gene expression at a distance along the chromosome from the transcriptional start site. While enhancers and TFBS have been identified for several immune responsive genes in Drosophila, the vast majority of enhancers that regulate immune induced genes are unknown and uncharacterized. Without knowledge of these regulatory elements, our understanding of how immune signal pathways interact at the cis-regulatory level and the grammar needed for this type of gene expression is limited. To identify immune responsive enhancers, we stimulated the major immune pathways, Toll and IMD, both individually and together in S2 cells and measured enhancer activity via STARR-seq (Self transcribing active regulatory-region sequencing). This activity-based assay identifies sequences that can drive their own expression upon activation of immune signaling pathways in a high-throughput manner. A large-scale analysis of immune enhancers permits us to characterize the regulatory grammar found in these sequences, as well as unknown immune TFBS. Additionally, by stimulating two immune pathways in this experiment we can investigate the role enhancers play in producing synergetic gene expression. The identification of immune enhancers will provide insights into how animals use regulatory sequences control their gene expression response to a rapidly changing environment and thus survive infection from pathogens.