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PER3
The PER3 gene encodes the period circadian protein homolog 3 protein in humans. PER3 is a paralog to the PER1 and PER2 genes. It is a circadian gene associate with delayed sleep phase syndrome in humans. History The Per3 gene was independently cloned by two research groups (Kobe University School of Medicine and the Harvard Medical School) who both published their discovery in June 1998. The mammalian Per3 was discovered by searching for homologous cDNA sequences to Per2. The amino acid sequence of the mouse PERIOD3 protein (mPER3) is between 37-56% similar to the other two PER proteins. Function This gene is a member of the Period family of genes. It is expressed in a circadian pattern in the suprachiasmatic nucleus (SCN), the primary circadian pacemaker in the mammalian brain. Genes in this family encode components of the circadian rhythms of locomotor activity, metabolism, and behavior. Circadian expression in the SCN continues in constant darkness, and a shift in the ligh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PER2
PER2 is a protein in mammals encoded by the ''PER2'' gene. ''PER2'' is noted for its major role in circadian rhythms. Discovery The ''per ''gene'' ''was first discovered using forward genetics in ''Drosophila melanogaster, Drosophilla melanogaster'' in 1971. Mammal, Mammalian Per2 was discovered by in 1997 through a search for homologous cDNA sequences to PER1. It is more similar to Drosophila ''Period (gene), per'' than its Sequence homology, paralogs. Later experiments in also identified ''Per2 ''in humans. Function ''PER2'' is a member of the Period family of genes and is expressed in a circadian pattern in the suprachiasmatic nucleus, the primary circadian pacemaker in the mammalian brain. Genes in this family encode components of the circadian rhythm, circadian clock, which regulates the daily rhythms of locomotor activity, metabolism, and behavior. Circadian expression of these genes and their encoded proteins in the suprachiasmatic nucleus. Human PER2 is involved in h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delayed Sleep Phase Disorder
Delayed sleep phase disorder (DSPD), more often known as delayed sleep phase syndrome and also as delayed sleep–wake phase disorder, is a delaying of a person's circadian rhythm (biological clock) compared to those of societal norms. The disorder affects the timing of biological rhythms including sleep, peak period of alertness, core body temperature, and hormonal cycles. The diagnosis of this disorder is currently a point of contention among specialists of sleep disorders. Many insomnia-related disorders can present significantly differently between patients, and circadian rhythm disorders and melatonin related disorders are not well understood by modern medical science. The orexin system was identified only in 1998, yet it appears intimately implicated in human sleep-wake systems. Evidence for the plasticity of human circadian rhythm cycles has been provided by multiple studies. In one example, several dozen volunteers spent many months underground in a French cave, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian Rhythm
A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., Endogeny (biology), endogenous) and responds to the environment (Entrainment (chronobiology), entrained by the environment). These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in animals, plants, fungi and cyanobacteria. The term ''circadian'' comes from the Latin ''wikt:circa#Latin, circa'', meaning "approximately", and ''dies'', meaning "day". Processes with 24-hour cycles are more generally called diurnal rhythms; diurnal rhythms should not be called circadian rhythms unless they can be confirmed as endogenous, and not environmental. Although circadian rhythms are endogenous, they are adjusted to the local environment by external cues called zeitgebers (German for "time givers"), which include light, temperature and redox cy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PER1
The PER1 gene encodes the period circadian protein homolog 1 protein in humans. Function The PER1 protein is important to the maintenance of circadian rhythms in cells, and may also play a role in the development of cancer. This gene is a member of the period family of genes. It is expressed with a daily oscillating circadian rhythm, or an oscillation that cycles with a period of approximately 24 hours. PER1 is most notably expressed in the region of the brain called the suprachiasmatic nucleus (SCN), which is the primary circadian pacemaker in the mammalian brain. PER1 is also expressed throughout mammalian peripheral tissues. Genes in this family encode components of the circadian rhythms of locomotor activity, metabolism, and behavior. Circadian expression of PER1 in the suprachiasmatic nucleus will free-run in constant darkness, meaning that the 24-hour period of the cycle will persist without the aid of external light cues. Subsequently, a shift in the light/dark cycle evo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian
A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., endogenous) and responds to the environment ( entrained by the environment). These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in animals, plants, fungi and cyanobacteria. The term ''circadian'' comes from the Latin ''circa'', meaning "approximately", and ''dies'', meaning "day". Processes with 24-hour cycles are more generally called diurnal rhythms; diurnal rhythms should not be called circadian rhythms unless they can be confirmed as endogenous, and not environmental. Although circadian rhythms are endogenous, they are adjusted to the local environment by external cues called zeitgebers (German for "time givers"), which include light, temperature and redox cycles. In clinical settings, an abnormal circadian rhythm in humans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suprachiasmatic Nucleus
The suprachiasmatic nucleus or nuclei (SCN) is a tiny region of the brain in the hypothalamus, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. The neuronal and hormonal activities it generates regulate many different body functions in a 24-hour cycle. The mouse SCN contains approximately 20,000 neurons. The SCN interacts with many other regions of the brain. It contains several cell types and several different peptides (including vasopressin and vasoactive intestinal peptide) and neurotransmitters. Neuroanatomy The SCN is situated in the anterior part of the hypothalamus immediately dorsal, or ''superior'' (hence supra) to the optic chiasm (CHO) bilateral to (on either side of) the third ventricle. The nucleus can be divided into ventrolateral and dorsolateral portions, also known as the core and shell, respectively. These regions differ in their expression of the clock genes, the core expresses them in response to stimuli whereas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian Rhythm
A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., Endogeny (biology), endogenous) and responds to the environment (Entrainment (chronobiology), entrained by the environment). These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in animals, plants, fungi and cyanobacteria. The term ''circadian'' comes from the Latin ''wikt:circa#Latin, circa'', meaning "approximately", and ''dies'', meaning "day". Processes with 24-hour cycles are more generally called diurnal rhythms; diurnal rhythms should not be called circadian rhythms unless they can be confirmed as endogenous, and not environmental. Although circadian rhythms are endogenous, they are adjusted to the local environment by external cues called zeitgebers (German for "time givers"), which include light, temperature and redox cy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian Clock
A circadian clock, or circadian oscillator, is a biochemical oscillator that cycles with a stable phase (waves), phase and is synchronized with solar time. Such a clock's ''in vivo'' period is necessarily almost exactly 24 hours (the earth's current day, solar day). In most living things, internally synchronized circadian clocks make it possible for the organism to anticipate daily environmental changes corresponding with the day–night cycle and adjust its biology and behavior accordingly. The term circadian derives from the Latin ''circa'' (about) ''dies'' (a day), since when taken away from external cues (such as environmental light), they do not run to exactly 24 hours. Clocks in humans in a lab in constant low light, for example, will average about 24.2 hours per day, rather than 24 hours exactly. The normal body clock oscillates with an endogenous period of exactly 24 hours, it Entrainment (chronobiology), entrains, when it receives sufficient daily corrective signals from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suprachiasmatic Nucleus
The suprachiasmatic nucleus or nuclei (SCN) is a tiny region of the brain in the hypothalamus, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. The neuronal and hormonal activities it generates regulate many different body functions in a 24-hour cycle. The mouse SCN contains approximately 20,000 neurons. The SCN interacts with many other regions of the brain. It contains several cell types and several different peptides (including vasopressin and vasoactive intestinal peptide) and neurotransmitters. Neuroanatomy The SCN is situated in the anterior part of the hypothalamus immediately dorsal, or ''superior'' (hence supra) to the optic chiasm (CHO) bilateral to (on either side of) the third ventricle. The nucleus can be divided into ventrolateral and dorsolateral portions, also known as the core and shell, respectively. These regions differ in their expression of the clock genes, the core expresses them in response to stimuli whereas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronotype
A chronotype is the behavioral manifestation of underlying circadian rhythm's myriad of physical processes. A person's chronotype is the propensity for the individual to sleep at a particular time during a 24-hour period. ''Eveningness'' (delayed sleep period; most active and alert in the evening) and ''morningness'' (advanced sleep period; most active and alert in the morning) are the two extremes with most individuals having some flexibility in the timing of their sleep period. However, across development there are changes in the propensity of the sleep period with pre-pubescent children preferring an advanced sleep period, adolescents preferring a delayed sleep period and many elderly preferring an advanced sleep period. The causes and regulation of chronotypes, including developmental change, individual propensity for a specific chronotype, and flexible versus fixed chronotypes have yet to be determined. However, research is beginning to shed light on these questions, such as t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription Factors
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The function of TFs is to regulate—turn on and off—genes in order to make sure that they are expressed in the desired cells at the right time and in the right amount throughout the life of the cell and the organism. Groups of TFs function in a coordinated fashion to direct cell division, cell growth, and cell death throughout life; cell migration and organization (body plan) during embryonic development; and intermittently in response to signals from outside the cell, such as a hormone. There are up to 1600 TFs in the human genome. Transcription factors are members of the proteome as well as regulome. TFs work alone or with other proteins in a complex, by promoting (as an activator), or blocking (as a repressor) the recruitment of RNA po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of four-legged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, and it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matching p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
