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PER (circadian Clock)
Period (per) is a gene located on the X chromosome of ''Drosophila melanogaster''. Oscillations in levels of both ''per'' transcript and its corresponding protein PER have a period of approximately 24 hours and together play a central role in the molecular mechanism of the ''Drosophila'' biological clock driving circadian rhythms in eclosion and locomotor activity. Mutations in the per gene can shorten (''perS''), lengthen (''perL''), and even abolish (''per0'') the period of the circadian rhythm. Discovery The period gene and three mutants (''perS'', ''perL'', and ''per0'') were isolated in an EMS mutagenesis screen by Ronald Konopka and Seymour Benzer in 1971. The ''perS'', ''perL'', and ''per0'' mutations were found to not complement each other, so it was concluded that the three phenotypes were due to mutations in the same gene. The discovery of mutants that altered the period of circadian rhythms in eclosion and locomotor activity (''perS'' and ''perL'') indicated the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila Melanogaster
''Drosophila melanogaster'' is a species of fly (an insect of the Order (biology), order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly", "pomace fly", or "banana fly". In the wild, ''D. melanogaster'' are attracted to rotting fruit and fermenting beverages, and are often found in orchards, kitchens and pubs. Starting with Charles W. Woodworth's 1901 proposal of the use of this species as a model organism, ''D. melanogaster'' continues to be widely used for biological research in genetics, physiology, microbial pathogenesis, and Life history theory, life history evolution. ''D. melanogaster'' was the first animal to be Fruit flies in space, launched into space in 1947. As of 2017, six Nobel Prizes have been awarded to drosophilists for their work using the insect. ''Drosophila melanogaster'' is typically used in research owing to its rapid life cycle, relatively simple genetics with on ... [...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] |
Synaptic Transmission
Neurotransmission (Latin: ''transmissio'' "passage, crossing" from ''transmittere'' "send, let through") is the process by which signaling molecules called neurotransmitters are released by the axon terminal of a neuron (the presynaptic neuron), and bind to and react with the receptors on the dendrites of another neuron (the postsynaptic neuron) a short distance away. Changes in the concentration of ions, such as Ca2+, Na+, K+, underlie both chemical and electrical activity in the process. The increase in calcium levels is essential and can be promoted by protons. A similar process occurs in retrograde neurotransmission, where the dendrites of the postsynaptic neuron release retrograde neurotransmitters (e.g., endocannabinoids; synthesized in response to a rise in intracellular calcium levels) that signal through receptors that are located on the axon terminal of the presynaptic neuron, mainly at GABAergic and glutamatergic synapses. Neurotransmission is regulated by several d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Transgene
A transgene is a gene that has been transferred naturally, or by any of a number of genetic engineering techniques, from one organism to another. The introduction of a transgene, in a process known as transgenesis, has the potential to change the phenotype of an organism. ''Transgene'' describes a segment of DNA containing a gene sequence that has been isolated from one organism and is introduced into a different organism. This non-native segment of DNA may either retain the ability to produce RNA or protein in the transgenic organism or alter the normal function of the transgenic organism's genetic code. In general, the DNA is incorporated into the organism's germ line. For example, in higher vertebrates this can be accomplished by injecting the foreign DNA into the cell nucleus, nucleus of a fertilized ovum. This technique is routinely used to introduce human disease genes or other genes of interest into strains of Laboratory mouse, laboratory mice to study the function or pathol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-term Memory
Long-term memory (LTM) is the stage of the Atkinson–Shiffrin memory model in which informative knowledge is held indefinitely. It is defined in contrast to sensory memory, the initial stage, and short-term or working memory, the second stage, which persists for about 18 to 30 seconds. LTM is grouped into two categories known as explicit memory (declarative memory) and implicit memory (non-declarative memory). Explicit memory is broken down into episodic and semantic memory, while implicit memory includes procedural memory and emotional conditioning. Stores The idea of separate memories for short- and long-term storage originated in the 19th century. One model of memory developed in the 1960s assumed that all memories are formed in one store and transfer to another store after a small period of time. This model is referred to as the "modal model", most famously detailed by Shiffrin. The model states that memory is first stored in sensory memory, which has a large capacit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Radiation
A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists of the shortest wavelength electromagnetic waves, typically shorter than those of X-rays. With frequencies above 30 exahertz () and wavelengths less than 10 picometers (), gamma ray photons have the highest photon energy of any form of electromagnetic radiation. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation ''gamma rays'' based on their relatively strong penetration of matter; in 1900, he had already named two less penetrating types of decay radiation (discovered by Henri Becquerel) alpha rays and beta rays in ascending order of penetrating power. Gamma rays from radioactive decay are in the energy range ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-myc
''Myc'' is a family of regulator genes and proto-oncogenes that code for transcription factors. The ''Myc'' family consists of three related human genes: ''c-myc'' ( MYC), ''l-myc'' ( MYCL), and ''n-myc'' ( MYCN). ''c-myc'' (also sometimes referred to as ''MYC'') was the first gene to be discovered in this family, due to homology with the viral gene ''v-myc''. In cancer, ''c-myc'' is often constitutively (persistently) expressed. This leads to the increased expression of many genes, some of which are involved in cell proliferation, contributing to the formation of cancer. A common human translocation involving ''c-myc'' is critical to the development of most cases of Burkitt lymphoma. Constitutive upregulation of ''Myc'' genes have also been observed in carcinoma of the cervix, colon, breast, lung and stomach. Myc is thus viewed as a promising target for anti-cancer drugs. Unfortunately, Myc possesses several features that have rendered it difficult to drug to date, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gadd45
The Growth Arrest and DNA Damage or ''gadd45'' genes, including GADD45A (originally termed gadd45) GADD45B (originally termed MyD118), and GADD45G (originally termed CR6), are implicated as stress sensors that modulate the response of mammalian cells to genotoxic/ physiological stress, and modulate tumor formation. Gadd45 proteins interact with other proteins implicated in stress responses, including PCNA, p21, Cdc2/CyclinB1, MEKK4, and p38 kinase. GADD45 proteins regulate differentiation at the two cell stage of embryogenesis, a key stage of zygotic genome activation. GADD45 likely acts by promoting TET-mediated DNA demethylation leading to the induction of expression of genes necessary for zygote activation. Overexpression of the ''GADD45'' gene in the ''Drosophila melanogaster'' nervous system significantly increases longevity Longevity may refer to especially long-lived members of a population, whereas ''life expectancy'' is defined Statistics, statistically as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclin A
Cyclin A is a member of the cyclin family, a group of proteins that function in regulating progression through the cell cycle. The stages that a cell passes through that culminate in its division and replication are collectively known as the cell cycle Since the successful division and replication of a cell is essential for its survival, the cell cycle is tightly regulated by several components to ensure the efficient and error-free progression through the cell cycle. One such regulatory component is cyclin A which plays a role in the regulation of two different cell cycle stages. Types Cyclin A was first identified in 1983 in sea urchin embryos. Since its initial discovery, homologues of cyclin A have been identified in numerous eukaryotes including '' Drosophila'', ''Xenopus'', mice, and in humans but has not been found in lower eukaryotes like yeast. The protein exists in both an embryonic form and somatic form. A single cyclin A gene has been identified in Drosophila while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
