Replication origins are shown as red circles. Gene expression levels are indicated by the color gradient from origin-proximal loci with high expression levels (red) to origin distal loci with low expression (blue). Paired loop anchors between co-regulated genes are indicated within dotted circles and binding sites for the Sulfolobus-specific SMC superfamily protein ClsN indicated. The Sulfolobus A and B compartments are indicated by boxing.