Synonyms:GIG13, hPER3, PER3, period homolog 3 Background:The suprachiasmatic nuclei(SCN) of the anterior hypothalamus function as a circadian clock in the mammalian brain, generating circadian rhythms in physiology and behavior. The period homolog genesPer3 is an important component of the circadian clock system. PER3 plays a role in cell proliferation, apoptosis,DNA damage response, cell cycle control, and treatment response of chemotherapy agents in cancers.