Differential functions of upstream and intronic HOT regions shape dlg-1 transcription and C. elegans development

High occupancy target (HOT) regions, genomic sites bound by many transcription factors, are found across eukaryotes, but their physiological roles remain unclear. We characterized two HOT regions in the Caenorhabditis elegans dlg-1 locus containing transcription start sites: one upstream the coding sequence and one in the first intron. The upstream region is essential for proper transcription and proper animal development, while the intronic region modestly enhances transcription in epidermal cells. Our findings reveal the functions of HOT regions in animal development, expanding the repertoire of gene regulation strategies in C. elegans.