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Repression Of Heat Shock Gene Expression (ROSE) Element
The repression of heat shock gene expression (ROSE) element is an RNA element found in the 5' UTR of some heat shock protein's mRNAs. The ROSE element is an RNA thermometer that negatively regulates heat shock gene expression. The secondary structure is thought to be altered by temperature, thus it is an RNA thermometer. This structure blocks access to the ribosome binding site at normal temperatures. During heat shock however, the structure changes freeing the ribosome binding site and allowing expression to occur. A partial structure of this RNA element has been determined using NMR. ROSE1 and ROSEAT2 ROSE1 and ROSEAT2 are specific examples of ROSE elements. ROSE1 is found in '' Bradyrhizobium japonicum'' whereas ROSEAT2 is a closely related element from ''Agrobacterium tumefaciens''. The two RNA elements have similar secondary structures with ROSE1 having an extra hairpin. All ROSE elements contain a characteristic 'bulged G' opposite the Shine-Dalgarno sequence binding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hsp90 Cis-regulatory Element
The Hsp90 cis regulatory element is an RNA element (RNA thermometer) found in the 5' UTR of the ''Drosophila'' hsp90 mRNA. It is required for increased translational efficiency during the heat shock response. The hsp90 gene product is involved in the ''Drosophila'' heat shock response. Translation of the hsp90 mRNA is very inefficient under normal growth temperatures; when heat shock occurs, translation becomes more efficient. This is mediated via this regulatory element. See also * ROSE element *FourU thermometer __NOTOC__ FourU thermometers are a class of non-coding RNA thermometers found in ''Salmonella''. They are named 'FourU' due to the four highly conserved uridine nucleotides found directly opposite the Shine-Dalgarno sequence on hairpin II (''pict ... References External links * Cis-regulatory RNA elements {{molecular-cell-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bradyrhizobium Japonicum
''Bradyrhizobium japonicum'' is a species of legume- root nodulating, microsymbiotic nitrogen-fixing bacteria. The species is one of many Gram-negative, rod-shaped bacteria commonly referred to as rhizobia. Within that broad classification, which has three groups, taxonomy studies using DNA sequencing indicate that ''B. japonicum'' belongs within homology group II. Uses Agriculture ''B. japonicum'' is added to legume seed to improve crop yields, particularly in areas where the bacterium is not native (e.g. Arkansas soils). Often the inoculate is adhered to the seeds prior to planting using a sugar solution. Research A strain of ''B. japonicum'', USDA110, has been in use as a model organism since 1957. It is widely used to study molecular genetics, plant physiology, and plant ecology due to its relatively superior symbiotic nitrogen-fixation activity with soybean (i.e. compared to other rhizobia species). Its entire genome was sequenced in 2002, revealing that the spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FourU Thermometer
__NOTOC__ FourU thermometers are a class of non-coding RNA thermometers found in ''Salmonella''. They are named 'FourU' due to the four highly conserved uridine nucleotides found directly opposite the Shine-Dalgarno sequence on hairpin II (''pictured''). RNA thermometers such as FourU control regulation of temperature via heat shock proteins in many prokaryotes. FourU thermometers are relatively small RNA molecules, only 57 nucleotides in length, and have a simple two-hairpin structure. FourU are found in the 5' untranslated region of the gene for heat shock protein ''Salmonella agsA'', they repress translation of this protein by base-pairing the Shine-Dalgarno sequence of the gene's mRNA. This prevents ribosomes from binding the start codon of the gene. They are also found in the 5'UTR of ''htrA'' (high temperature requirement) genes in ''Salmonella'' and ''E.coli.'' In ''V. cholerae'' fourU thermometer in the 5' of ''toxT'' controls its temperature-dependent translation. At hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanobacterial RNA Thermometers
The first cyanobacterial RNA thermometer ( RNAT) Hsp17 was found in the 5'UTR of '' Synechocystis'' heat shock ''hsp17'' mRNA. Further study demonstrated that cyanobacteria commonly use RNATs to control the translation of their heat shock genes. HspA is a homolog of Hsp17 in thermophilic '' Thermosynechococcus elongatus''. Two more thermometers were found in the 5'UTRs of mesophilic cyanobacteria '' A. variabilis'' and ''Nostoc ''Nostoc'', also known as star jelly, troll’s butter, spit of moon, fallen star, witch's butter (not to be confused with the fungi commonly known as witches' butter), and witch’s jelly, is the most common genus of cyanobacteria found in vari ...'' ''sp''. The first RNAT called avashort was shown to regulate translation by masking the AUG translation start site. The second RNAT called avalong, as it has an extended initial hairpin, might involve tertiary interactions and has similarities to the ROSE element. References Non-coding RNA Cis-reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quorum Sensing
In biology, quorum sensing or quorum signalling (QS) is the ability to detect and respond to cell population density by gene regulation. As one example, QS enables bacteria to restrict the expression of specific genes to the high cell densities at which the resulting phenotypes will be most beneficial. Many species of bacteria use quorum sensing to coordinate gene expression according to the density of their local population. In a similar fashion, some social insects use quorum sensing to determine where to nest. Quorum sensing in pathogenic bacteria activates host immune signaling and prolongs host survival, by limiting the bacterial intake of nutrients, such as tryptophan, which further is converted to serotonin. As such, quorum sensing allows a Commensalism, commensal interaction between host and pathogenic bacteria. Quorum sensing may also be useful for cancer cell communications. In addition to its function in biological systems, quorum sensing has several useful applications ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudomonas Aeruginosa
''Pseudomonas aeruginosa'' is a common encapsulated, gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. aeruginosa'' is a multidrug resistant pathogen recognized for its ubiquity, its intrinsically advanced antibiotic resistance mechanisms, and its association with serious illnesses – hospital-acquired infections such as ventilator-associated pneumonia and various sepsis syndromes. The organism is considered opportunistic insofar as serious infection often occurs during existing diseases or conditions – most notably cystic fibrosis and traumatic burns. It generally affects the immunocompromised but can also infect the immunocompetent as in hot tub folliculitis. Treatment of ''P. aeruginosa'' infections can be difficult due to its natural resistance to antibiotics. When more advanced antibiotic drug regimens are needed adverse effects may re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Translation (genetics)
In molecular biology and genetics, translation is the process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesize proteins after the process of transcription of DNA to RNA in the cell's nucleus. The entire process is called gene expression. In translation, messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. The polypeptide later folds into an active protein and performs its functions in the cell. The ribosome facilitates decoding by inducing the binding of complementary tRNA anticodon sequences to mRNA codons. The tRNAs carry specific amino acids that are chained together into a polypeptide as the mRNA passes through and is "read" by the ribosome. Translation proceeds in three phases: # Initiation: The ribosome assembles around the target mRNA. The first tRNA is attached at the start codon. # Elongation: The last tRNA validated by the small ribosomal subunit (''accommodation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudomonas
''Pseudomonas'' is a genus of Gram-negative, Gammaproteobacteria, belonging to the family Pseudomonadaceae and containing 191 described species. The members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a wide range of niches. Their ease of culture ''in vitro'' and availability of an increasing number of ''Pseudomonas'' strain genome sequences has made the genus an excellent focus for scientific research; the best studied species include ''P. aeruginosa'' in its role as an opportunistic human pathogen, the plant pathogen '' P. syringae'', the soil bacterium '' P. putida'', and the plant growth-promoting ''P. fluorescens, P. lini, P. migulae'', and ''P. graminis''. Because of their widespread occurrence in water and plant seeds such as dicots, the pseudomonads were observed early in the history of microbiology. The generic name ''Pseudomonas'' created for these organisms was defined in rather vague terms by Walter Migula i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleotide
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common nutrients by the liver. Nucleotides are composed of three subunit molecules: a nucleobase, a five-carbon sugar (ribose or deoxyribose), and a phosphate group consisting of one to three phosphates. The four nucleobases in DNA are guanine, adenine, cytosine and thymine; in RNA, uracil is used in place of thymine. Nucleotides also play a central role in metabolism at a fundamental, cellular level. They provide chemical energy—in the form of the nucleoside triphosphates, adenosine triphosphate (ATP), guanosine triphosphate (GTP), cytidine triphosphate (CTP) and uridine triphosphate (UTP)—throughout the cell for the many cellular func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stem-loop
Stem-loop intramolecular base pairing is a pattern that can occur in single-stranded RNA. The structure is also known as a hairpin or hairpin loop. It occurs when two regions of the same strand, usually complementary in nucleotide sequence when read in opposite directions, base-pair to form a double helix that ends in an unpaired loop. The resulting structure is a key building block of many RNA secondary structures. As an important secondary structure of RNA, it can direct RNA folding, protect structural stability for messenger RNA (mRNA), provide recognition sites for RNA binding proteins, and serve as a substrate for enzymatic reactions. Formation and stability The formation of a stem-loop structure is dependent on the stability of the resulting helix and loop regions. The first prerequisite is the presence of a sequence that can fold back on itself to form a paired double helix. The stability of this helix is determined by its length, the number of mismatches or bulges it co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agrobacterium Tumefaciens
''Agrobacterium radiobacter'' (more commonly known as ''Agrobacterium tumefaciens'') is the causal agent of crown gall disease (the formation of tumours) in over 140 species of eudicots. It is a rod-shaped, Gram-negative soil bacterium. Symptoms are caused by the insertion of a small segment of DNA (known as the T-DNA, for 'transfer DNA', not to be confused with tRNA that transfers amino acids during protein synthesis), from a plasmid into the plant cell, which is incorporated at a semi-random location into the plant genome. Plant genomes can be engineered by use of ''Agrobacterium'' for the delivery of sequences hosted in T-DNA binary vectors. ''Agrobacterium tumefaciens'' is an Alphaproteobacterium of the family Rhizobiaceae, which includes the nitrogen-fixing legume symbionts. Unlike the nitrogen-fixing symbionts, tumor-producing ''Agrobacterium'' species are pathogenic and do not benefit the plant. The wide variety of plants affected by ''Agrobacterium'' makes it of gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Structure
Protein secondary structure is the three dimensional conformational isomerism, form of ''local segments'' of proteins. The two most common Protein structure#Secondary structure, secondary structural elements are alpha helix, alpha helices and beta sheets, though beta turns and omega loops occur as well. Secondary structure elements typically spontaneously form as an intermediate before the protein protein folding, folds into its three dimensional protein tertiary structure, tertiary structure. Secondary structure is formally defined by the pattern of hydrogen bonds between the Amine, amino hydrogen and carboxyl oxygen atoms in the peptide backbone chain, backbone. Secondary structure may alternatively be defined based on the regular pattern of backbone Dihedral angle#Dihedral angles of proteins, dihedral angles in a particular region of the Ramachandran plot regardless of whether it has the correct hydrogen bonds. The concept of secondary structure was first introduced by Kaj Ulrik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
