 The human "timeless" protein (hTIM) has been shown to be required for the production of electrical oscillations output by the suprachiasmatic nucleus (SCN), the major clock governing all tissue-specific circadian rhythms of the body.This protein also interacts with the products of major clock genes CLOCK, BMAL, PER1, PER2 and PER3.Sancar and colleagues investigated whether hTIM played a similar role to orthologs in "C. elegans" and other types of yeast, which are known to play important roles in the cell cycle.