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Timeless (gene)
Timeless (''tim'') is a gene in multiple species but is most notable for its role in '' Drosophila'' for encoding TIM, an essential protein that regulates circadian rhythm. ''Timeless'' mRNA and protein oscillate rhythmically with time as part of a transcription-translation negative feedback loop involving the '' period'' (''per'') gene and its protein. Discovery In 1994, ''timeless'' was discovered through forward genetic screening performed by Jeffery L. Price while working in the lab of Michael W. Young. This gene was found when they noticed an arrhythmic ''tim''01 mutant via a P element screen. The tim01 mutation caused arrhythmic behavior, defined by the lack of ability to establish proper circadian rhythms. In 1995, the timeless gene was cloned by Amita Sehgal and partners in the lab of Michael W. Young. Unlike the Drosophila ''timeless'' gene, homologs have been discovered in other species that are non-essential for circadian rhythm. The discovery of ''timeless'' fol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila
''Drosophila'' (), from Ancient Greek δρόσος (''drósos''), meaning "dew", and φίλος (''phílos''), meaning "loving", is a genus of fly, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies (sometimes referred to as "true fruit flies"); tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly. One species of ''Drosophila'' in particular, ''Drosophila melanogaster'', has been heavily used in research in genetics and is a common model organism in developmental biology. The terms "fruit fly" and "''Drosophila''" are often used synonymously with ''D. melanogaster'' in modern biological literatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-terminus
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amine group is bonded to the carboxylic group of another amino acid, making it a chain. That leaves a free carboxylic group at one end of the peptide, called the C-terminus, and a free amine group on the other end called the N-terminus. By convention, peptide sequences are written N-terminus to C-terminus, left to right (in LTR writing systems). This correlates the translation direction to the text direction, because when a protein is translated from messenger RNA, it is created from the N-terminus to the C-terminus, as amino acids are added to the carboxyl end of the protein. Chemistry Each amino acid has an amine group and a carboxylic group. Amino acids link to one another by peptide bonds which form through a dehydration reaction that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vrille Gene
''Vrille'' (vri) is a bZIP transcription factor found on chromosome 2 in ''Drosophila melanogaster''. Vrille mRNA and protein product (VRI) oscillate predictably on a 24-hour timescale and interact with other circadian clock genes to regulate circadian rhythms in ''Drosophila''. It is also a regulator in embryogenesis; it is expressed in multiple cell types during multiple stages in development, coordinating embryonic dorsal/ventral polarity, wing-vein differentiation, and ensuring tracheal integrity. It is also active in the embryonic gut but the precise function there is unknown. Mutations in ''vri'' alter circadian period and cause circadian arrhythmicity and developmental defects in ''Drosophila''. Discovery Helene George and Regine Terracol discovered the first ''vrille'' alleles (''vri'' and ''vri'') in 1997 by EMS-mutagenesis assay and found their products to be transcription factors involved in embryogenesis. Justin Blau elucidated additional "vrille" implications in 1999 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorylation
In biochemistry, phosphorylation is described as the "transfer of a phosphate group" from a donor to an acceptor. A common phosphorylating agent (phosphate donor) is ATP and a common family of acceptor are alcohols: : This equation can be written in several ways that are nearly equivalent that describe the behaviors of various protonated states of ATP, ADP, and the phosphorylated product. As is clear from the equation, a phosphate group per se is not transferred, but a phosphoryl group (PO3-). Phosphoryl is an electrophile. This process and its inverse, dephosphorylation, are common in biology. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License. Protein phosphorylation often activates (or deactivates) many enzymes. During respiration Phosphorylation is essential to the processes of both anaerobic and aerobic respiration, which involve the production of adenosine triphosphate (ATP), the "high-energy" exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casein Kinase
Casein kinase, a type of kinase enzyme, may refer to: * Casein kinase 1, serine/threonine-selective protein kinase family * Casein kinase 2 Casein kinase 2 ()(CK2/CSNK2) is a serine/threonine-selective protein kinase that has been implicated in cell cycle control, DNA repair, regulation of the circadian rhythm, and other cellular processes. De-regulation of CK2 has been linked to tumor ..., a serine/threonine-selective protein kinase Protein kinases {{Enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptochrome
Cryptochromes (from the Greek κρυπτός χρώμα, "hidden colour") are a class of flavoproteins found in plants and animals that are sensitive to blue light. They are involved in the circadian rhythms and the sensing of magnetic fields in a number of species. The name ''cryptochrome'' was proposed as a ''portmanteau'' combining the '' chromatic'' nature of the photoreceptor, and the '' cryptogamic'' organisms on which many blue-light studies were carried out. The genes ''CRY1'' and ''CRY2'' encode the proteins CRY1 and CRY2, respectively. Cryptochromes are classified into plant Cry and animal Cry. Animal Cry can be further categorized into insect type (Type I) and mammal-like (Type II). CRY1 is a circadian photoreceptor whereas CRY2 is a clock repressor which represses Clock/Cycle (Bmal1) complex in insects and vertebrates. In plants, blue-light photoreception can be used to cue developmental signals. Besides chlorophylls, cryptochromes are the only proteins known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian Clock Of Drosophila
A circadian rhythm (), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., endogenous) and responds to the environment (is entrained by the environment). Circadian rhythms are regulated by a circadian clock whose primary function is to rhythmically co-ordinate biological processes so they occur at the correct time to maximize the fitness of an individual. Circadian rhythms have been widely observed in animals, plants, fungi and cyanobacteria and there is evidence that they evolved independently in each of these kingdoms of life. The term ''circadian'' comes from the Latin ', meaning "around", and ', 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 adjuste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entrainment (chronobiology)
In the study of chronobiology, entrainment refers to the synchronization of a biological clock to an environmental cycle. An example is the interaction between circadian rhythms and environmental cues, such as light and temperature. Entrainment helps organisms adapt their bodily processes according to the timing of a changing environment. For example, entrainment is manifested during travel between time zones, hence why humans experience jet lag. Biological rhythms are endogenous; they persist even in the absence of environmental cues as they are driven by an internal mechanism, most notably the circadian clock. Of the several possible cues (known as '' zeitgebers,'' German for 'time-givers') that can contribute to entrainment of the circadian clock, light has the greatest impact. Units of circadian time (CT) are used to describe entrainment to refer to the relationship between the rhythm and the light signal/pulse. Modes of entrainment There are two general modes of entrainm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycle (gene)
''Cycle'' (''cyc'') is a gene in ''Drosophila melanogaster'' that encodes the CYCLE protein (CYC). The ''Cycle'' gene ''(''c''yc)'' is expressed in a variety of cell types in a circadian manner. It is involved in controlling both the sleep-wake cycle and circadian regulation of gene expression by promoting transcription in a negative feedback mechanism. The c''yc'' gene is located on the left arm of chromosome 3 and codes for a transcription factor containing a basic helix–loop–helix (bHLH) domain and a PAS domain. The 2.17 kb c''yc'' gene is divided into 5 coding exons totaling 1,625 base pairs which code for 413 aminos acid residues. Currently 19 alleles are known for c''yc'' ., accessdate=10 April 2013 Orthologs performing the same function in other species include basic helix-loop-helix ARNT-like protein 1 (ARNTL) and Aryl hydrocarbon receptor nuclear translocator-like 2 ( ARNTL2). Function ''Cycle'' is primarily known for its role in the genetic transcription ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clock (gene)
A clock or chronometer is a device that measures and displays time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, and the year. Devices operating on several physical processes have been used over the millennia. Some predecessors to the modern clock may be considered "clocks" that are based on movement in nature: A sundial shows the time by displaying the position of a shadow on a flat surface. There is a range of duration timers, a well-known example being the hourglass. Water clocks, along with sundials, are possibly the oldest time-measuring instruments. A major advance occurred with the invention of the verge escapement, which made possible the first mechanical clocks around 1300 in Europe, which kept time with oscillating timekeepers like balance wheels., pp. 103–104., p. 31. Traditionally, in horology (the study of timekeeping), the term ''clock'' was us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-hybrid Screening
Two-hybrid screening (originally known as yeast two-hybrid system or Y2H) is a molecular biology technique used to discover protein–protein interactions (PPIs) and DNA-binding protein#Protein–DNA interactions, protein–DNA interactions by testing for physical interactions (such as binding) between two proteins or a single protein and a DNA molecule, respectively. The premise behind the test is the activation of Upstream and downstream (DNA), downstream reporter gene(s) by the binding of a transcription factor onto an upstream activating sequence (UAS). For two-hybrid screening, the transcription factor is split into two separate fragments, called the DNA-binding domain (DBD or often also abbreviated as BD) and activating domain (AD). The BD is the protein domain, domain responsible for DNA-binding protein, binding to the UAS and the AD is the domain responsible for the activation of Transcription (genetics), transcription. The Y2H is thus a protein-fragment complementation a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michael Rosbash
Michael Morris Rosbash (born March 7, 1944) is an American geneticist and chronobiologist. Rosbash is a professor and researcher at Brandeis University and investigator at the Howard Hughes Medical Institute. Rosbash's research group cloned the ''Drosophila'' period gene in 1984 and proposed the Transcription Translation Negative Feedback Loop for circadian clocks in 1990. In 1998, they discovered the cycle gene, clock gene, and cryptochrome photoreceptor in ''Drosophila'' through the use of forward genetics, by first identifying the phenotype of a mutant and then determining the genetics behind the mutation. Rosbash was elected to the National Academy of Sciences in 2003. Along with Michael W. Young and Jeffrey C. Hall, he was awarded the 2017 Nobel Prize in Physiology or Medicine "for their discoveries of molecular mechanisms controlling the circadian rhythm". Life Michael Rosbash was born in Kansas City, Missouri. His parents, Hilde and Alfred Rosbash, were Jewish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
