Circadian clocks are endogenous timers that enable plants to synchronize biological processes with daily and seasonal environmental conditions in order to allocate resources during the most beneficial times of day and...Circadian clocks are endogenous timers that enable plants to synchronize biological processes with daily and seasonal environmental conditions in order to allocate resources during the most beneficial times of day and year. The circadian clock regulates a number of central plant activities, including growth, develop- ment, and reproduction, primarily through controlling a substantial proportion of transcriptional activity and protein function. This review examines the roles that alleles of circadian clock genes have played in domestication and improvement of crop plants. The focus here is on three groups of circadian clock genes essential to clock function in Arabidopsis thaliana： PSEUDO-RESPONSE REGULATORs, GIGANTEA, and the evening complex genes EARL Y FLOWERING 3, EARLY FLOWERING 4, and LUX ARRHYTHMO. Homol- ogous genes from each group underlie quantitative trait loci that have beneficial influences on key agricul- tural traits, especially flowering time but also yield, biomass, and biennial growth habit. Emerging insights into circadian clock regulation of other fundamental plant processes, including responses to abiotic and biotic stresses, are discussed to highlight promising avenues for further crop improvement.展开更多
Clock genes create a complicated molecular time-keeping system consisting of multiple positive and negative feedback loops at transcriptional and translational levels. This circadian system coordinates and regulates m...Clock genes create a complicated molecular time-keeping system consisting of multiple positive and negative feedback loops at transcriptional and translational levels. This circadian system coordinates and regulates multiple cellular procedures implicated in cancer development such as metabolism, cell cycle and DNA damage response. Recent data support that molecules such as CLOCK1, BMAL1 and PER and CRY proteins have various effects on c-Myc/p21 and Wnt/β-catenin pathways and influence multiple steps of DNA damage response playing a critical role in the preservation of genomic integrity in normal and cancer cells. Notably, all these events have already been related to the development and progression of colorectal cancer (CRC). Recent data highlight critical correlations between clock genes’ expression and pathogenesis, progression, aggressiveness and prognosis of CRC. Increased expression of positive regulators of this circadian system such as BMAL1 has been related to decrease overall survival while decreased expression of negative regulators such as PER2 and PER3 is connected with poorer differentiation, increased aggressiveness and worse prognosis. The implications of these molecules in DNA repair systems explain their involvement in the development of CRC but at the same time provide us with novel targets for modern therapeutic approaches for patients with advanced CRC.展开更多
[A Review] The biorhythms of every species are precisely regulated to adapt the environmental changes. The function of biorhythms is controlled by the clock genes in either a single cell or the whole body. The functio...[A Review] The biorhythms of every species are precisely regulated to adapt the environmental changes. The function of biorhythms is controlled by the clock genes in either a single cell or the whole body. The function of clock genes depends on the feedback circles that are composed by the interactions among the clock components. Many studies indicate that circadian clock is closely related to diseases. Several cardiovascular diseases such as myocardial ischemia and myocardial infarction show overt circadian rhythms, indicating that clock genes may play an important role in such kinds of diseases.展开更多
Many aspects of cellular physiology display circadian(approximately 24-h)rhythms.Dysfunction of the circadian clock molecular circuitry is associated with human health derangements,including neurodegeneration,increase...Many aspects of cellular physiology display circadian(approximately 24-h)rhythms.Dysfunction of the circadian clock molecular circuitry is associated with human health derangements,including neurodegeneration,increased risk of cancer,cardiovascular diseases and the metabolic syndrome.Viruses triggering hepatitis depend tightly on the host cell synthesis machinery for their own replication,survival and spreading.Recent evidences support a link between the circadian clock circuitry and viruses’biological cycle within host cells.Currently,in vitro models for chronobiological studies of cells infected with viruses need to be implemented.The establishment of such in vitro models would be helpful to better understand the link between the clock gene machinery and viral replication/viral persistence in order to develop specifically targeted therapeutic regimens.Here we review the recent literature dealing with the interplay between hepatitis B and C viruses and clock genes.展开更多
Summary： This study investigated the effects of benazepril administered in the morning or evening on the diurnal variation of renin-angiotensin-aldosterone system （RAAS） and clock genes in the kidney. The male Wist...Summary： This study investigated the effects of benazepril administered in the morning or evening on the diurnal variation of renin-angiotensin-aldosterone system （RAAS） and clock genes in the kidney. The male Wistar rat models of 5/6 subtotal nephrectomy （STNx） were established. Animals were ran- domly divided into 4 groups： sham STNx group （control）, STNx group, morning benazepril group （MB） and evening benazepril group （EB）. Benazepril was intragastfically administered at a dose of 10 mg/kg/day at 07：00 and 19：00 in the MB group and EB group respectively for 12 weeks. All the animals were synchronized to the light：dark cycle of 12：12 for 12 weeks. Systolic blood pressure （SBP）, 24-h urinary protein excretion and renal function were measured at 11 weeks. Blood samples and kidneys were collected every 4 h throughout a day to detect the expression pattern of renin activity （RA）, angio- tensin Ⅱ （Ang Ⅱ ） and aldosterone （Aid） by radioimmunoassay （RIA） and the mRNA expression profile of clock genes （bmall, dbp and per2） by real-time PCR at 12 weeks. Our results showed that no signifi- cant differences were noted in the SBP, 24-h urine protein excretion and renal function between the MB and EB groups. There were no significant differences in average Aid and RA content of a day between the MB group and EB group. The expression peak of bmall mRNA was phase-delayed by 4 to 8 h, and the diurnal variation of per2 and dbp mRNA diminished in the MB and EB groups compared with the control and STNx groups. It was concluded when the similar SBP reduction, RAAS inhibition and clock gene profile were achieved with optimal dose of benazepril, morning versus evening dosing of benazepril has the same renoprotection effects.展开更多
The timing of major life-history events, such as migration and moult, is set by endogenous circa-dian and circannual clocks, that have been well characterized at the molecular level. Conversely,the genetic sources of ...The timing of major life-history events, such as migration and moult, is set by endogenous circa-dian and circannual clocks, that have been well characterized at the molecular level. Conversely,the genetic sources of variation in phenology and in other behavioral traits have been sparsely ad-dressed. It has been proposed that inter-individual variability in the timing of seasonal events mayarise from allelic polymorphism at phenological candidate genes involved in the signaling cascadeof the endogenous clocks. In this study of a long-distance migratory passerine bird, the willowwarbler Phylloscopus trochilus, we investigated whether allelic variation at 5 polymorphic loci of 4candidate genes （Adcyapl, Clock, Crebl, and Npas2）, predicted 2 major components of the annualschedule, namely timing of spring migration across the central Mediterranean sea and moultspeed, the latter gauged from ptilochronological analyses of tail feathers moulted in the Africanwinter quarters. We identified a novel Clockgene locus （Clock region 3） showing polyQ polymorph-ism, which was however not significantly associated with any phenotypic trait. Npas2 allele sizepredicted male （but not female） spring migration date, with males bearing longer alleles migratingsignificantly earlier than those bearing shorter alleles. Crebl allele size significantly predicted male（but not female） moult speed, longer alleles being associated with faster moult. All othergenotype-phenotype associations were statistically non-significant. These findings provide newevidence for a role of candidate genes in modulating the phenology of different circannual activ-ities in long-distance migratory birds, and for the occurrence of sex-specific candidate gene effects.展开更多
A growing body of evidence indicates that exposure to environmental chemicals can contribute to the etiology of obesity by inappropriately stimulating adipogenesis as well as perturbing lipid metabolism and energy bal...A growing body of evidence indicates that exposure to environmental chemicals can contribute to the etiology of obesity by inappropriately stimulating adipogenesis as well as perturbing lipid metabolism and energy balance. One potential mechanism by which chemical exposure can influence lipid metabolism is through disturbance of circadian rhythms, endogenously-driven cycles of roughly 24 hr in length that coordinate biochemical, physiological, and behavioral processes in all organisms. Here we show for the first time that exposure to endocrine disrupting compounds（EDCs）, including the pesticide tributyltin, two commercial flame retardants, and a UV-filter chemical found in sunscreens,can perturb both circadian clocks and lipid metabolism in vertebrates. Exposure of developing zebrafish to EDCs affects core clock activity and leads to a remarkable increase in lipid accumulation that is reminiscent of the effects observed for longdaysin, a known disruptor of circadian rhythms. Our data reveal a novel obesogenic mechanism of action for environmental chemicals, an observation which warrants further research. Because circadian clocks regulate a wide variety of physiological processes, identification of environmental chemicals capable of perturbing these systems may provide important insights into the development of environmentally-induced metabolic disease.展开更多
Objective: To investigate the effects of 72 hours continuous sleep deprivation (SD) on circadian clock gene expression and oxidative stress in the rat liver. Methods: Twenty healthy male Sprague-Dawley rats were divid...Objective: To investigate the effects of 72 hours continuous sleep deprivation (SD) on circadian clock gene expression and oxidative stress in the rat liver. Methods: Twenty healthy male Sprague-Dawley rats were divided into 2 groups (n = 10 each) using a random number table: normal control group (group C), sleep deprivation group (group SD). Group SD was treated with a modified multiple platform water environment method. After 72 hours sleep deprived, the levels of AST (Aspartate transaminase ) and ALT (Alanine aminotransferase) in serum were determined. The contents of malondialdehyde (MDA), the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the liver tissue of the rats were examined in both two groups. The expression levels of CLOCK, BMAL1 and CRY1 protein in liver tissue were examined by Western blotting. Results: Compared with group C, the content of MDA, and the levels of AST and ALT in serum were significantly increased (P Conclusion: 72 hours continuous sleep deprivation can downregulate the expression of circadian clock gene and promote oxidative stress in rats.展开更多
In insects,facultative diapause is a state of developmental arrest mainly induced by photoperiod or temperature that allows insects to survive adverse environmental conditions.Understanding how insect initiates facult...In insects,facultative diapause is a state of developmental arrest mainly induced by photoperiod or temperature that allows insects to survive adverse environmental conditions.Understanding how insect initiates facultative diapause and prepares diapause can provide us new insights to study developmental and evolutionary biology.It has been shown that the circadian clock genes can participate in photoperiodic measurement and regulate reproductive diapause initiation through JH signaling in short-day-induced winter diapause.However,how circadian clock genes translate photoperiodic information into downstream JH signaling for diapause destiny and then affect diapause preparation remains largely unknown.In the present study,we investigate this in the cabbage beetle Colaphellus bowringi which undergoes reproductive diapause under long-day condition.We respectively knocked down two circadian clock negative regulators,period(per)and timeless(tim),in the 3-day-old larvae(most sensitive to photoperiod),and dsgfp treatment was served as a control.Under the diapause-inducing photoperiod(16L:8D),knocking down per and tim significantly decreased the rate of burrowing behavior.And mtany female beetles of the per and tim RNAi showed developed ovary,decreased lipid accumulation and downregulated expression of stress resistance genes.The JHinduced genes,Kr-h1,JHE1,Vg1,and Vg2, significantly increased in the females with suppression of per and tim.It implied that suppression of per and tim during diapause initiation phase(DIP)could activate the JH signaling in the female adults.Before the beetles enter into diapause preparation phase(DPP),we used RNA sequencing to analyize gene expression profiles after per and tim RNAi.It showed that many differentially expressed genes were enriched in environmental information processing,such as mTOR and TGF-beta signaling pathway.To ask whether per and tim also regulate diapause preparation,we knocked down these two genes in the female adults during DPP.It showed that the diapause destiny was n展开更多
文摘Circadian clocks are endogenous timers that enable plants to synchronize biological processes with daily and seasonal environmental conditions in order to allocate resources during the most beneficial times of day and year. The circadian clock regulates a number of central plant activities, including growth, develop- ment, and reproduction, primarily through controlling a substantial proportion of transcriptional activity and protein function. This review examines the roles that alleles of circadian clock genes have played in domestication and improvement of crop plants. The focus here is on three groups of circadian clock genes essential to clock function in Arabidopsis thaliana： PSEUDO-RESPONSE REGULATORs, GIGANTEA, and the evening complex genes EARL Y FLOWERING 3, EARLY FLOWERING 4, and LUX ARRHYTHMO. Homol- ogous genes from each group underlie quantitative trait loci that have beneficial influences on key agricul- tural traits, especially flowering time but also yield, biomass, and biennial growth habit. Emerging insights into circadian clock regulation of other fundamental plant processes, including responses to abiotic and biotic stresses, are discussed to highlight promising avenues for further crop improvement.
文摘Clock genes create a complicated molecular time-keeping system consisting of multiple positive and negative feedback loops at transcriptional and translational levels. This circadian system coordinates and regulates multiple cellular procedures implicated in cancer development such as metabolism, cell cycle and DNA damage response. Recent data support that molecules such as CLOCK1, BMAL1 and PER and CRY proteins have various effects on c-Myc/p21 and Wnt/β-catenin pathways and influence multiple steps of DNA damage response playing a critical role in the preservation of genomic integrity in normal and cancer cells. Notably, all these events have already been related to the development and progression of colorectal cancer (CRC). Recent data highlight critical correlations between clock genes’ expression and pathogenesis, progression, aggressiveness and prognosis of CRC. Increased expression of positive regulators of this circadian system such as BMAL1 has been related to decrease overall survival while decreased expression of negative regulators such as PER2 and PER3 is connected with poorer differentiation, increased aggressiveness and worse prognosis. The implications of these molecules in DNA repair systems explain their involvement in the development of CRC but at the same time provide us with novel targets for modern therapeutic approaches for patients with advanced CRC.
文摘[A Review] The biorhythms of every species are precisely regulated to adapt the environmental changes. The function of biorhythms is controlled by the clock genes in either a single cell or the whole body. The function of clock genes depends on the feedback circles that are composed by the interactions among the clock components. Many studies indicate that circadian clock is closely related to diseases. Several cardiovascular diseases such as myocardial ischemia and myocardial infarction show overt circadian rhythms, indicating that clock genes may play an important role in such kinds of diseases.
基金Supported by RC1303GA49 and Italian Ministry of Health(Pazienza V)MV and VP are supported by Bando GR-2010-2311017 and by the"5x1000"voluntary contributions to IRCCS"Casa Sollievo della Sofferenza"Hospital(Vinciguerra M and Pazienza V)and the Associazione Italiana per la Ricerca sul Cancro(AIRC)program MyFAG(Vinciguerra M)
文摘Many aspects of cellular physiology display circadian(approximately 24-h)rhythms.Dysfunction of the circadian clock molecular circuitry is associated with human health derangements,including neurodegeneration,increased risk of cancer,cardiovascular diseases and the metabolic syndrome.Viruses triggering hepatitis depend tightly on the host cell synthesis machinery for their own replication,survival and spreading.Recent evidences support a link between the circadian clock circuitry and viruses’biological cycle within host cells.Currently,in vitro models for chronobiological studies of cells infected with viruses need to be implemented.The establishment of such in vitro models would be helpful to better understand the link between the clock gene machinery and viral replication/viral persistence in order to develop specifically targeted therapeutic regimens.Here we review the recent literature dealing with the interplay between hepatitis B and C viruses and clock genes.
基金supported by grants from the Department of Public Health of Hubei Province of China (No. 2012Z-B08)the Health Bureau of Wuhan City of China (No. WX12C10)
文摘Summary： This study investigated the effects of benazepril administered in the morning or evening on the diurnal variation of renin-angiotensin-aldosterone system （RAAS） and clock genes in the kidney. The male Wistar rat models of 5/6 subtotal nephrectomy （STNx） were established. Animals were ran- domly divided into 4 groups： sham STNx group （control）, STNx group, morning benazepril group （MB） and evening benazepril group （EB）. Benazepril was intragastfically administered at a dose of 10 mg/kg/day at 07：00 and 19：00 in the MB group and EB group respectively for 12 weeks. All the animals were synchronized to the light：dark cycle of 12：12 for 12 weeks. Systolic blood pressure （SBP）, 24-h urinary protein excretion and renal function were measured at 11 weeks. Blood samples and kidneys were collected every 4 h throughout a day to detect the expression pattern of renin activity （RA）, angio- tensin Ⅱ （Ang Ⅱ ） and aldosterone （Aid） by radioimmunoassay （RIA） and the mRNA expression profile of clock genes （bmall, dbp and per2） by real-time PCR at 12 weeks. Our results showed that no signifi- cant differences were noted in the SBP, 24-h urine protein excretion and renal function between the MB and EB groups. There were no significant differences in average Aid and RA content of a day between the MB group and EB group. The expression peak of bmall mRNA was phase-delayed by 4 to 8 h, and the diurnal variation of per2 and dbp mRNA diminished in the MB and EB groups compared with the control and STNx groups. It was concluded when the similar SBP reduction, RAAS inhibition and clock gene profile were achieved with optimal dose of benazepril, morning versus evening dosing of benazepril has the same renoprotection effects.
文摘The timing of major life-history events, such as migration and moult, is set by endogenous circa-dian and circannual clocks, that have been well characterized at the molecular level. Conversely,the genetic sources of variation in phenology and in other behavioral traits have been sparsely ad-dressed. It has been proposed that inter-individual variability in the timing of seasonal events mayarise from allelic polymorphism at phenological candidate genes involved in the signaling cascadeof the endogenous clocks. In this study of a long-distance migratory passerine bird, the willowwarbler Phylloscopus trochilus, we investigated whether allelic variation at 5 polymorphic loci of 4candidate genes （Adcyapl, Clock, Crebl, and Npas2）, predicted 2 major components of the annualschedule, namely timing of spring migration across the central Mediterranean sea and moultspeed, the latter gauged from ptilochronological analyses of tail feathers moulted in the Africanwinter quarters. We identified a novel Clockgene locus （Clock region 3） showing polyQ polymorph-ism, which was however not significantly associated with any phenotypic trait. Npas2 allele sizepredicted male （but not female） spring migration date, with males bearing longer alleles migratingsignificantly earlier than those bearing shorter alleles. Crebl allele size significantly predicted male（but not female） moult speed, longer alleles being associated with faster moult. All othergenotype-phenotype associations were statistically non-significant. These findings provide newevidence for a role of candidate genes in modulating the phenology of different circannual activ-ities in long-distance migratory birds, and for the occurrence of sex-specific candidate gene effects.
基金financial support of the European Union(FP7-PEOPLE-IEF,03197 Obesity and Light)the Netherlands Organization for Scientific Research(VIDI/864.09.005 and ASPASIA/015.006.018)
文摘A growing body of evidence indicates that exposure to environmental chemicals can contribute to the etiology of obesity by inappropriately stimulating adipogenesis as well as perturbing lipid metabolism and energy balance. One potential mechanism by which chemical exposure can influence lipid metabolism is through disturbance of circadian rhythms, endogenously-driven cycles of roughly 24 hr in length that coordinate biochemical, physiological, and behavioral processes in all organisms. Here we show for the first time that exposure to endocrine disrupting compounds（EDCs）, including the pesticide tributyltin, two commercial flame retardants, and a UV-filter chemical found in sunscreens,can perturb both circadian clocks and lipid metabolism in vertebrates. Exposure of developing zebrafish to EDCs affects core clock activity and leads to a remarkable increase in lipid accumulation that is reminiscent of the effects observed for longdaysin, a known disruptor of circadian rhythms. Our data reveal a novel obesogenic mechanism of action for environmental chemicals, an observation which warrants further research. Because circadian clocks regulate a wide variety of physiological processes, identification of environmental chemicals capable of perturbing these systems may provide important insights into the development of environmentally-induced metabolic disease.
文摘Objective: To investigate the effects of 72 hours continuous sleep deprivation (SD) on circadian clock gene expression and oxidative stress in the rat liver. Methods: Twenty healthy male Sprague-Dawley rats were divided into 2 groups (n = 10 each) using a random number table: normal control group (group C), sleep deprivation group (group SD). Group SD was treated with a modified multiple platform water environment method. After 72 hours sleep deprived, the levels of AST (Aspartate transaminase ) and ALT (Alanine aminotransferase) in serum were determined. The contents of malondialdehyde (MDA), the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the liver tissue of the rats were examined in both two groups. The expression levels of CLOCK, BMAL1 and CRY1 protein in liver tissue were examined by Western blotting. Results: Compared with group C, the content of MDA, and the levels of AST and ALT in serum were significantly increased (P Conclusion: 72 hours continuous sleep deprivation can downregulate the expression of circadian clock gene and promote oxidative stress in rats.
基金Funded by the National Natural Science Foundation of China(31701842)
文摘In insects,facultative diapause is a state of developmental arrest mainly induced by photoperiod or temperature that allows insects to survive adverse environmental conditions.Understanding how insect initiates facultative diapause and prepares diapause can provide us new insights to study developmental and evolutionary biology.It has been shown that the circadian clock genes can participate in photoperiodic measurement and regulate reproductive diapause initiation through JH signaling in short-day-induced winter diapause.However,how circadian clock genes translate photoperiodic information into downstream JH signaling for diapause destiny and then affect diapause preparation remains largely unknown.In the present study,we investigate this in the cabbage beetle Colaphellus bowringi which undergoes reproductive diapause under long-day condition.We respectively knocked down two circadian clock negative regulators,period(per)and timeless(tim),in the 3-day-old larvae(most sensitive to photoperiod),and dsgfp treatment was served as a control.Under the diapause-inducing photoperiod(16L:8D),knocking down per and tim significantly decreased the rate of burrowing behavior.And mtany female beetles of the per and tim RNAi showed developed ovary,decreased lipid accumulation and downregulated expression of stress resistance genes.The JHinduced genes,Kr-h1,JHE1,Vg1,and Vg2, significantly increased in the females with suppression of per and tim.It implied that suppression of per and tim during diapause initiation phase(DIP)could activate the JH signaling in the female adults.Before the beetles enter into diapause preparation phase(DPP),we used RNA sequencing to analyize gene expression profiles after per and tim RNAi.It showed that many differentially expressed genes were enriched in environmental information processing,such as mTOR and TGF-beta signaling pathway.To ask whether per and tim also regulate diapause preparation,we knocked down these two genes in the female adults during DPP.It showed that the diapause destiny was n
