The molecular components of mammalian circadian clocks are elusive. We have isolated a human gene termed RIGUI that encodes a bHLH/PAS protein 44% homologous to Drosophila period. The highly conserved mouse homolog (m-rigui) is expressed in a circadian pattern in the suprachiasmatic nucleus (SCN), the master regulator of circadian clocks in mammals. Circadian expression in the SCN continues in ...

PURPOSE Circadian rhythms are central to vision and retinal physiology. A circadian clock located within the retina controls various rhythmic processes including melatonin synthesis in photoreceptors. In the present study, we evaluated the rhythmic expression of clock genes and clock output genes in retinal explants maintained for several days in darkness. METHODS Retinas were dissected from ...

BACKGROUND The mammalian ovary is controlled by a number of biological rhythms, which regulate the recruitment and release of mature oocytes. The main objective of this study was to investigate the role of cellular clock proteins during follicle maturation in the mouse estrous ovary. METHODS Immunohistochemical (IHC) studies were performed on ovaries from 50 estrous staged mice culled at two ...

Numerous peripheral tissues possess self-sustaining daily biologic rhythms that are regulated at the molecular level by clock genes such as PER1, PER2, CLOCK, and BMAL1. Physiological function of nasal mucosa exhibits rhythmic variability to a day-night environmental cycle. Nevertheless, little is known of the expression and distribution pattern of clock genes in nasal mucosa. The present study...

Characterization of diurnal core clock gene expression across brain regions of mice with differential degree of glucocorticoid receptor knockout" (2015). Undergraduate Honors Theses. Paper 975. Abstract Circadian rhythms are maintained through the self-regulatory, oscillatory molecular clock, which includes Per1, Per2, and Bmal1 clock genes, among others. Disruptions to clock gene expression ha...

Locomotor activity rhythms in a significant proportion of Siberian hamsters (Phodopus sungorus sungorus) become arrhythmic after the light-dark (LD) cycle is phase-delayed by 5 h. Arrhythmia is apparent within a few days and persists indefinitely despite the presence of the photocycle. The failure of arrhythmic hamsters to regain rhythms while housed in the LD cycle, as well as the lack of any ...

Restricted feeding (RF) schedules provide a cycle of fasting and feeding each day and induce circadian rhythms in food-anticipatory activity. In addition, daily rhythms in the expression of circadian clock genes, such as rhythms in Period1 (PER1) or Period2 (PER2), are also shifted in many brain areas that are important for the regulation of motivation and emotion. In order to differentiate bra...