Remodeling of Il4-Il13-Il5 locus underlies selective gene expression

The type 2 cytokines, interleukin (IL)-4, IL-13 and IL-5 reside within a multigene cluster. Both innate (ILC2) and adaptive T helper 2 (TH2) lymphocytes secrete type 2 cytokines with diverse production spectra. Using transcription factor footprint and chromatin accessibility, we systemically cataloged regulatory elements (REs) denoted as SHS-I/II, KHS-I/II, +6.5kbIl13, 5HS-I(a, b, c, d, e), 5HS-II and 5HS-III(a, b, c) across the extended Il4-Il13-Il5 locus in mice. Physical proximities among REs were coordinately remodeled in three-dimensional space after cell activation, leading to divergent compartmentalization of Il4, Il13 and Il5 with varied combinations of REs. Deletions of REs revealed no single RE solely accounted for selective regulation of a given cytokine in vivo. Instead, individual RE differentially contribute to proper genomic positioning of REs and target genes. RE deletions resulted in context-dependent dysregulation of cytokine expression and immune response in tissue. Thus, signal-dependent remodeling of three-dimensional configuration underlies divergent cytokine outputs from the type 2 loci. O’Shea and colleagues examine the three-dimensional chromatin architecture of the type 2 cytokine locus and how it differs between innate ILC2 cells and adaptive TH2 lymphocytes.