Light-induced phase shifts in mice lacking mPER1 or mPER2.
Three homologs of the Drosophila Period gene have been identified in mammals. In mice, these three genes (mPer1, mPer2, and mPer3) have distinct roles in the circadian clockwork. While products of mPer1 and mPer2 play important roles in the maintenance of circadian rhythmicity, mPer3 gene products are dispensable for rhythmicity. Several studies also implicate mPER1 and mPER2 in transduction of photic information to the core circadian clockwork. The phase-shifting effects of light were examined in mPER1-deficient and mPER2-deficient mice using T cycle paradigms, in which mice received 1 h of light per day at an interval of T hours. To assess phase delays, repeated exposure to 1 h of light per day at T = 24 was used. To assess phase advances, exposure to 1-h light pulses at T = 22-h intervals was used. The degeneration of rhythmicity in the mutant mice prevented assessment of a response in most cases. Nevertheless, clear examples of phase delays and phase advances were observed in both mPer1 and mPer2 mutant mice. These results are not consistent with the hypothesis that mPER1 and mPER2 play necessary and nonoverlapping roles in mediating the effects of light on the circadian dock.
Bae
Kiho
K
Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Weaver
David R
DR
D000483:Alleles; D000818:Animals; D018797:Cell Cycle Proteins; D002940:Circadian Rhythm / Q000235:genetics* / Q000502:physiology*; D005838:Genotype; D008027:Light; D051379:Mice; D018345:Mice, Knockout; D009043:Motor Activity / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics*; D056950:Period Circadian Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors
D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C539023:Per1 protein, mouse; C513312:Per2 protein, mouse; D056950:Period Circadian Proteins; D014157:Transcription Factors