Cycle of period gene expression in a diurnal mammal (Spermophilus tridecemlineatus): implications for nonphotic phase shifting.
Ground squirrels, Spermophilus tridecemlineatus, were kept in a 12:12 h light-dark cycle. As expected for a diurnal species, their locomotor activity occurred almost entirely in the daytime. Expression of mPer1 and mPer2 in the suprachiasmatic nucleus was studied at six time points by in situ hybridization. For both these genes, mRNA was highest in the first part of the subjective day (about zeitgeber time 5). This is close to the time when mPer1 and mPer2 expression is maximal in nocturnal rodents. These results have implications for understanding nonphotic phase response curves in diurnal species and thereby for guiding research on nonphotic phase shifting in people.
Mrosovsky
N
N
Department of Zoology, University of Toronto, Ontario, Canada. mro@zoo.utoronto.ca
Edelstein
K
K
Hastings
M H
MH
Maywood
E S
ES
D000818:Animals; D001923:Brain Chemistry / Q000502:physiology; D018797:Cell Cycle Proteins; D002940:Circadian Rhythm / Q000502:physiology*; D004594:Electrophysiology; D005786:Gene Expression Regulation / Q000502:physiology*; D017403:In Situ Hybridization; D009687:Nuclear Proteins / Q000235:genetics*; D056950:Period Circadian Proteins; D010507:Periodicity; D012333:RNA, Messenger / Q000096:biosynthesis; D012589:Sciuridae / Q000502:physiology*; D013493:Suprachiasmatic Nucleus / Q000378:metabolism; D014157:Transcription Factors
D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C513312:Per2 protein, mouse; D056950:Period Circadian Proteins; D012333:RNA, Messenger; D014157:Transcription Factors