Electronic Thesis and Dissertation Repository


Master of Science


Microbiology and Immunology


Kim, Sung O.


IL-1β is a potent inflammatory cytokine promptly expressed in activated myeloid cells. PU.1 is a lineage-determining transcription factor that regulates myeloid-specific genes by activating distal enhancers. This study addresses the functional importance of a potential enhancer of IL-1β, and how PU.1 regulates its activity state. A putative enhancer RNA (eRNA) was transcribed from the enhancer, and eRNA knock-down with antisense oligonucleotides inhibited IL-1β production. Furthermore, enhancer-promoter interactions in stimulated macrophages were detected via chromatin conformation capture (3C) analysis. The role of PU.1 was examined in PU.1-overexpressed B16-BL6 cells, which responded to LPS and expressed IL-1β mRNA and eRNAs. Enhancer knock-out by CRISPR-Cas9 reduced IL-1β expression, supporting its identity as an enhancer. 3C analysis showed that enhancer-promoter interactions were established in a PU.1-dependent manner. We report that PU.1 activated the enhancer and restructured the chromatin architecture of IL-1β. This study unraveled new regulatory elements and their mechanisms in regulating IL-1β expression.