biostudies-literatureNumano RNIMH NIH HHS3716-21https://www.ebi.ac.uk/biostudies/studies/S-EPMC1450145biostudies-literatureUnknown103(10)Three mammalian Period (Per) genes, termed Per1, Per2, and Per3, have been identified as structural homologues of the Drosophila circadian clock gene, period (per). The three Per genes are rhythmically expressed in the suprachiasmatic nucleus (SCN), the central circadian pacemaker in mammals. The phases of peak mRNA levels for the three Per genes in the SCN are slightly different. Light sequentially induces the transcripts of Per1 and Per2 but not of Per3 in mice. These data and others suggest that each Per gene has a different but partially redundant function in mammals. To elucidate the function of Per1 in the circadian system in vivo, we generated two transgenic rat lines in which the mouse Per1 (mPer1) transcript was constitutively expressed under the control of either the human elongaProceedings of the National Academy of Sciences of the United States of AmericaConstitutive expression of the Period1 gene impairs behavioral and molecular circadian rhythms.PMC1450145MH56647R01 MH056647Sakaki YUmeda NMenaker MMori AYamada KTei HUeda MNumano RTakahashi RSujino MSamura TInouye STYamazaki SfalseConstitutive expression of the Period1 gene impairs behavioral and molecular circadian rhythms.Three mammalian Period (Per) genes, termed Per1, Per2, and Per3, have been identified as structural homologues of the Drosophila circadian clock gene, period (per). The three Per genes are rhythmically expressed in the suprachiasmatic nucleus (SCN), the central circadian pacemaker in mammals. The phases of peak mRNA levels for the three Per genes in the SCN are slightly different. Light sequentially induces the transcripts of Per1 and Per2 but not of Per3 in mice. These data and others suggest that each Per gene has a different but partially redundant function in mammals. To elucidate the function of Per1 in the circadian system in vivo, we generated two transgenic rat lines in which the mouse Per1 (mPer1) transcript was constitutively expressed under the control of either the human elonga2006-01-01T00:00:00Z2006 Mar2025-04-05T12:49:36.061Z2019-03-27T01:26:20ZS-EPMC14501451653745110.1073/pnas.0600060103