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LHY
The Late Elongated Hypocotyl gene (LHY), is an oscillating gene found in plants that functions as part of their circadian clock. LHY encodes components of mutually regulatory negative feedback loops with Circadian Clock Associated 1 (CCA1) in which overexpression of either results in dampening of both of their expression. This negative feedback loop affects the rhythmicity of multiple outputs creating a daytime protein complex. LHY was one of the first genes identified in the plant clock, along with TOC1 and CCA1. LHY and CCA1 have similar patterns of expression, which is capable of being induced by light.Lu, S. X. , and S. M., Andronis. "CIRCADIAN CLOCK ASSOCIATED1 and LATE ELONGATED HYPOCOTYL Function Synergistically in the Circadian Clock of Arabidopsis" Plant Physiology Vol. 150. (2009): 834–843. Single loss-of-function mutants in both genes result in seemingly identical phenotypes, but LHY cannot fully rescue the rhythm when CCA1 is absent, indicating that they may only b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian Clock Associated 1
Circadian Clock Associated 1 (CCA1) is a gene that is central to the Circadian clock, circadian oscillator of angiosperms. It was first identified in ''Arabidopsis thaliana'' in 1993. CCA1 interacts with LHY and TOC1 (gene), TOC1 to form the core of the oscillator system. CCA1 expression peaks at dawn. Loss of CCA1 function leads to a shortened period in the expression of many other genes. Discovery CCA1 was first identified in ''Arabidopsis thaliana'' by Elaine M. Tobin’s lab in University of California, Los Angeles, UCLA in 1993. Tobin’s lab was studying promoter fragments that contribute to light regulation of light-harvesting Chlorophyll A/B Binding Protein (LHCB), and noticed DNA-binding activity that had affinity for a specific light-responsive fragment of the LHCB promoter. This DNA-binding activity was designated as CA-1 because the binding is mostly to cytosine and adenine-rich sequences. They found that this binding activity is necessary for phytochrome response. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudo-response Regulator
Pseudo-response regulator (PRR) refers to a group of genes that are important in the plant circadian oscillator. There are four primary PRR proteins (PRR9, PRR7, PRR5 and TOC1/PRR1) that perform the majority of interactions with other proteins within the circadian oscillator, and another (PRR3) that has limited function. These genes are all paralogs of each other, and all repress the transcription of Circadian Clock Associated 1 ( CCA1) and Late Elongated Hypocotyl (LHY) at various times throughout the day. The expression of PRR9, PRR7, PRR5 and TOC1/PRR1 peak around morning, mid-day, afternoon and evening, respectively. As a group, these genes are one part of the three-part repressilator system that governs the biological clock in plants. Discovery Multiple labs identified the PRR genes as parts of the circadian clock in the 1990s. In 2000, Akinori Matsushika, Seiya Makino, Masaya Kojima, and Takeshi Mizuno were the first to understand PRR genes as pseudo-response repressor gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudo-response Regulator
Pseudo-response regulator (PRR) refers to a group of genes that are important in the plant circadian oscillator. There are four primary PRR proteins (PRR9, PRR7, PRR5 and TOC1/PRR1) that perform the majority of interactions with other proteins within the circadian oscillator, and another (PRR3) that has limited function. These genes are all paralogs of each other, and all repress the transcription of Circadian Clock Associated 1 ( CCA1) and Late Elongated Hypocotyl (LHY) at various times throughout the day. The expression of PRR9, PRR7, PRR5 and TOC1/PRR1 peak around morning, mid-day, afternoon and evening, respectively. As a group, these genes are one part of the three-part repressilator system that governs the biological clock in plants. Discovery Multiple labs identified the PRR genes as parts of the circadian clock in the 1990s. In 2000, Akinori Matsushika, Seiya Makino, Masaya Kojima, and Takeshi Mizuno were the first to understand PRR genes as pseudo-response repressor gene ... [...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] |
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] |
Oscillating Gene
In molecular biology, an oscillating gene is a gene that is expressed in a rhythmic pattern or in periodic cycles. Oscillating genes are usually circadian and can be identified by periodic changes in the state of an organism. Circadian rhythms, controlled by oscillating genes, have a period of approximately 24 hours. For example, plant leaves opening and closing at different times of the day or the sleep-wake schedule of animals can all include circadian rhythms. Other periods are also possible, such as 29.5 days resulting from circalunar rhythms or 12.4 hours resulting from circatidal rhythms. Oscillating genes include both core clock component genes and output genes. A core clock component gene is a gene necessary for to the pacemaker. However, an output oscillating gene, such as the AVP gene, is rhythmic but not necessary to the pacemaker. History The first recorded observations of oscillating genes come from the marches of Alexander the Great in the fourth century B.C.Von Dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscillating Gene
In molecular biology, an oscillating gene is a gene that is expressed in a rhythmic pattern or in periodic cycles. Oscillating genes are usually circadian and can be identified by periodic changes in the state of an organism. Circadian rhythms, controlled by oscillating genes, have a period of approximately 24 hours. For example, plant leaves opening and closing at different times of the day or the sleep-wake schedule of animals can all include circadian rhythms. Other periods are also possible, such as 29.5 days resulting from circalunar rhythms or 12.4 hours resulting from circatidal rhythms. Oscillating genes include both core clock component genes and output genes. A core clock component gene is a gene necessary for to the pacemaker. However, an output oscillating gene, such as the AVP gene, is rhythmic but not necessary to the pacemaker. History The first recorded observations of oscillating genes come from the marches of Alexander the Great in the fourth century B.C.Von Dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TOC1 (gene)
Timing of CAB expression 1 is a protein that in '' Arabidopsis thaliana'' is encoded by the TOC1 gene. TOC1 is also known as two-component response regulator-like APRR1. TOC1 was the first plant gene that, when mutated, yielded a circadian phenotype. It codes for the transcription factor TOC1, which affects the period of plants' circadian rhythms: built-in, malleable oscillations that repeat every 24 hours. The gene codes for a transcriptional repressor, TOC1, one of five pseudo-response regulators (PRR) that mediate the period of the circadian clock in plants. The TOC1 protein is involved in the clock's evening loop, which is a repressilator that directly inhibits transcription of morning loop genes LHY and CCA1. Toc1 gene is expressed in most plant structures and cells, and has its locus on chromosome 5. Historical context Discovery The TOC1 gene was initially discovered by Prof. Andrew Millar and colleagues in 1995 while Millar was a graduate student. Millar develo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andrew Millar (scientist)
Andrew John McWalter Millar, Fellow of the Royal Society, FRS, Fellow of the Royal Society of Edinburgh, FRSE is a Scottish chronobiology, chronobiologist, systems biology, systems biologist, and molecular genetics, molecular geneticist. Millar is a professor at The University of Edinburgh and also serves as its chair of systems biology. Millar is best known for his contributions to plant circadian rhythm, circadian biology; in the Steve A. Kay, Steve Kay lab, he pioneered the use of luciferase imaging to identify circadian mutants in ''Arabidopsis''. Additionally, Millar's group has implicated the ''ELF4'' gene in circadian control of flowering time in ''Arabidopsis''. Millar was elected to the Royal Society in 2012 and the Royal Society of Edinburgh in 2013. Life Andrew Millar was raised in Luxembourg. He later attended Cambridge University where he received a Bachelor of Arts in 1988, studying genetics and winning University Prizes for botany in 1987 and genetics in 1988. Af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plants
Plants are predominantly Photosynthesis, photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes (the archaea and bacteria). By one definition, plants form the clade Viridiplantae (Latin name for "green plants") which is sister of the Glaucophyte, Glaucophyta, and consists of the green algae and Embryophyte, Embryophyta (land plants). The latter includes the flowering plants, conifers and other gymnosperms, ferns and Fern ally, their allies, hornworts, liverworts, and mosses. Most plants are multicellular organisms. Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria. Their chloroplasts contain chlorophylls a and b, which gives them their green colo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feedback Loop
Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled carefully when applied to feedback systems: History Self-regulating mechanisms have existed since antiquity, and the idea of feedback had started to enter economic theory in Britain by the 18th century, but it was not at that time recognized as a universal abstraction and so did not have a name. The first ever known artificial feedback device was a float valve, for maintaining water at a constant level, invented in 270 BC in Alexandria, Egypt. This device illustrated the principle of feedback: a low water level opens the valve, the rising water then provides feedback into the system, closing the valve when the required level is reached. This then reoccurs in a circular fashion as the water level fluctuates. Centrifugal governors were u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum and polarization. Its speed in a vacuum, 299 792 458 metres a second (m/s), is one of the fundamental constants of nature. Like all types of electromagnetic radiation, visible light propagates by massless elementary particles called photons that represents the quanta of electromagnetic field, and can be analyzed as both waves and par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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