CLOCK and cancer: Such direct links between central energy metabolism and genome structure, impacting on gene expression, have recently been implicated also in mammalian regulatory systems such as the circadian clock [44] and cancer cell growth [45], [46], and are also suspected to play a major role in eubacterial growth regulation via negative supercoiling and ATP-dependent gyrase [47]–[51], which by itself was observed to underlie the genome-wide circadian remodeling of gene expression in cyanobacteria [52], [53].