Long-range DNA interactions at the IL-1/IL-36/IL-37 gene cluster (2q13) are induced by activation of monocytes

The interleukin-1 gene cluster occupies a 360kb region of chromosome 2q13 and contains nine homologous genes. These include agonists and antagonists of the parallel IL-1 and IL-36 systems, and IL1F7, the gene encoding IL-37. As the genes of the cluster are structurally and functionally related and have similar mRNA kinetics, we have sought evidence for gene induction-specific looping of chromatin in the IL-1 cluster by chromatin conformation capture (3C). We show here that IL1A, IL1B and IL1F7 regulatory regions come in close proximity in LPS stimulated cells but not in resting human monocytes. This suggests that IL1A, IL1B and IL1F7 are likely transcribed by the same transcription factory. One cardinal function of transcriptional Locus Control Region (LCR) is bringing map-distant activated genes into close physical proximity within the transcription factory. Our data show distant intergenic DNA segments are also in close proximity to the regulatory regions of the three genes. This may indicate that they are co-regulated and raise the possibility of a LCR within the cluster.