Disease relevance of Per1

• Ischemia-reperfusion leads to a persistent decrease of Per1 and Cry2, which may be related to the selective degeneration of amacrine and ganglion cells [1].

Psychiatry related information on Per1

• Furthermore, the similar diurnal pattern of Per1 and Per2 expression in diurnal and nocturnal rodents suggests that the circadian organization of locomotor activity rhythms probably relies on differential cellular integration mechanisms downstream of the clock [2].
• We found that LL had similar effects on cyclic locomotor and feeding behaviors and Per1 expression in the SCN but had no effect on rhythmic Period 1 expression in the OB [3].

High impact information on Per1

• The serum shock of rat-1 fibroblasts also results in a transient stimulation of c-fos and rper expression and thus mimics light-induced immediate-early gene expression in the suprachiasmatic nucleus [4].
• The rhythm matured gradually; at P10, the amplitude of Per1, Per2, and Bmal1 mRNA rhythms was more pronounced than at P3 [5].
• By using transgenic rats with a luciferase (luc) reporter, we assessed the effects of aging on the rhythm of expression of the Period 1 (Per1) gene in the suprachiasmatic nucleus (SCN) and in peripheral tissues [6].
• Glucose down-regulates Per1 and Per2 mRNA levels and induces circadian gene expression in cultured Rat-1 fibroblasts [7].
• Here, we show that cAMP, protein kinase C, glucocorticoid hormones and Ca2+ can all trigger a transient surge of Per1 transcription and elicit rhythmic gene expression in Rat-1 cells [8].

Biological context of Per1

• By using rat-1 fibroblasts, a model cell system of the peripheral clock, we found that an exchange of the culture medium triggered circadian gene expression that was preceded by slow down-regulation of Per1 and Per2 mRNA levels [7].
• The circadian rhythm of Per1 gene product in the rat suprachiasmatic nucleus and its modulation by seasonal changes in daylength [9].
• The rhythm was phase delayed by 6-8 h compared with the reported rhythm of Per1 mRNA in the rat SCN [L. Yan et al. Neuroscience 94 (1999) 141] [9].
• In the initial step of the circadian gene expression, a marked transient induction of Per1 was observed accompanied with CREB phosphorylation [10].
• Since it is known that these rats show a light-induced behavioral phase-shift throughout the subjective night with being strongest at subjective dawn, the present results suggest that the transient induction of Per1 in ventrolateral SCN neurons is a critical step in the resetting of the biological clock to environmental light-dark schedule [11].

Anatomical context of Per1

• The results presented here indicate a robust circadian expression of clock genes (e.g. Per1 and Bmal1) and the probable existence of a peripheral oscillator in the pancreas [12].
• The induction of Per1 gene in the suprachiasmatic nucleus, the center of the circadian clock, is assumed to play significant roles in the adjustment of the internal clock. cAMP is one of the intracellular mediators which activates Per1 transcription [13].
• In the reproductive tissues (uterus), biphasic rhythms in Per1 and Per2 mRNA were observed after E2 treatment [14].
• We studied the effects of constant lighting (LL) and of SCN lesions on behavioral rhythmicity and Period 1 (Per1) gene activity in the SCN and olfactory bulb (OB) [3].

Associations of Per1 with chemical compounds

• In nonreproductive peripheral tissues (liver and kidney), E2 delayed the phase and increased the amplitude of Per1 mRNA expression [14].
• AADC was co-expressed with vasopressin and the clock gene Per1 in the neurones of the SCN [15].
• Estrogen differentially regulates expression of Per1 and Per2 genes between central and peripheral clocks and between reproductive and nonreproductive tissues in female rats [14].
• In the brain, E2 treatment advanced the peak of Per2 mRNA expression in the SCN; however, it failed to affect the rhythm of Per2 mRNA expression in the CX and Per1 mRNA expression in both the SCN and the CX [14].
• Melatonin injection at the end of the subjective day also affects Per1 expression, leading to diminished mRNA levels [16].

Other interactions of Per1

• Light induced regulation of Per1 and Per2 mRNA expression have been suggested to take part in the clock resetting [17].
• In the present study, we investigated the effect of 5-HT2C receptor activation on various clock genes within the suprachiasmatic nucleus, including Per1 and Per2, which have previously been demonstrated as necessary for phase shifts [18].
• To determine whether melatonin feedback control on SCN activity implicates transcriptional regulation of the clock genes, we monitored the expression pattern of Per 1, 2, 3, Bmal1, Cry1 and AVP mRNAs after a single melatonin injection at the end of the subjective day [17].
• Furthermore, ICV injection of NMU increased the expression of Per1, but not Per2, in the SCN [19].
• Exposure to 30 min of light did not affect the expression of the three genes, while exposure to a longer light pulse (1 or 2 h) decreased AA-NAT and Per1 mRNA levels; Per2 mRNA levels were also decreased but only temporarily [20].

Analytical, diagnostic and therapeutic context of Per1

• With newly developed antisera, we substantiated the expression of Per1 and Per2 in these cells by single/double immunohistochemistry [21].
• Here we investigated the daily expression of the two core clock genes, Per1 and Per2, in the rat ovary using real-time RT-PCR, in situ hybridization histochemistry, and immunohistochemistry [21].

References