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Recent evidence has emerged that peroxisome proliferator-activated receptor alpha (PPARalpha), which is largely involved in lipid metabolism, can play an important role in connecting circadian biology and metabolism. In the present study, we investigated the mechanisms by which PPARalpha influences the pacemakers acting in the central clock located in the(More)
The physiological effects of estrogens are mediated by two intracellular transcription factors, the estrogen receptors (ERs), that regulate transcription of target genes through binding to specific DNA target sequences. Here we describe alterations in cellular responses to different ER agonists and to the anti-estrogenic compound tamoxifen resulting from(More)
Central and peripheral mammalian circadian clocks regulate a variety of behavioral and physiological processes through the rhythmic transcription of hundreds of clock-controlled genes. The circadian expression of many transcriptional regulators suggests that a major part of this circadian gene network is indirectly regulated by clock genes. Here we show(More)
The orphan receptors Rev-erbalpha and Rev-erbbeta are members of the nuclear receptors superfamily and act as transcriptional repressors. Rev-erbalpha is expressed with a robust circadian rhythm and is involved in liver metabolism through repression of the ApoA1 gene, but no role has been yet defined for Rev-erbbeta. To gain better understanding of their(More)
Circadian clocks are time-keeping systems found in most organisms. In zebrafish, expression of the clock gene Period3 (Per3) oscillates throughout embryogenesis in the central nervous system and the retina. Per3 rhythmic expression was free-running and was reset by light but not by the developmental delays caused by low temperature. The time of(More)
Complementary DNA fragments that encode central and C-terminal domains of rainbow trout estrogen receptor (rtER) were expressed in Escherichia coli as fusion proteins with glutathione-S-transferase (GST). Both fusion proteins were induced by IPTG and could readily be detected as a 53-55 kDa band in crude extracts or in insoluble fraction after(More)
Circadian (daily) rhythms are found in most living organisms from cyanobacteria to mammals. They are generated by an internal 'clock' that is reset by external time cues and that regulates a variety of physiological functions through downstream target genes. Analysis of the mammalian transcriptome using DNA microarrays is now identifying hundreds of(More)
Circadian ( approximately 24h) clocks are endogenous time-keeping systems that drive the daily biological rhythms observed in most living organisms. The oscillation is generated by a transcriptional/translational autoregulatory feedback loop that is reset by external time cues such as the light/dark cycle and which in turn controls rhythms in physiology and(More)
The transcription factor nuclear factor-kappaB (NF-kappaB) directs transcription of a large number of key molecules in immunological and inflammatory responses. The recently discovered inhibition of transcriptional activity of this factor by the activated glucocorticoid receptor (GR) provides a molecular basis for the potent antiinflammatory and(More)
Time plays an essential role in many biological systems, especially in cell cycle. Many models of biological systems rely on differential equations, but parameter identification is an obstacle to use differential frameworks. In this paper, we present a new hybrid modeling framework that extends René Thomas' discrete modeling. The core idea is to associate(More)