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Hsp17 Thermometer
In molecular biology, the ''Hsp17 thermometer'' is an RNA element (RNA thermometer) found in the 5' UTR of Hsp17 mRNA. Hsp17 is a cyanobacterial heat shock protein belonging to the Hsp20 family. At physiological temperature (28 degrees Celsius) the Hsp17 thermometer forms a hairpin structure, preventing translation of Hsp17. Under heat shock conditions the hairpin structure melts and translation takes place. See also *RNA thermometer * ROSE element * FourU thermometer * Hsp90 cis-regulatory element *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 ... References Cis-regulatory RNA elements {{molecular-cell-biology-stub ... [...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] |
Physiological
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical and physical functions in a living system. According to the classes of organisms, the field can be divided into medical physiology, animal physiology, plant physiology, cell physiology, and comparative physiology. Central to physiological functioning are biophysical and biochemical processes, homeostatic control mechanisms, and communication between cells. ''Physiological state'' is the condition of normal function. In contrast, ''pathological state'' refers to abnormal conditions, including human diseases. The Nobel Prize in Physiology or Medicine is awarded by the Royal Swedish Academy of Sciences for exceptional scientific achievements in physiology related to the field of medicine. Foundations Cells Although there are differe ... [...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] |
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] |
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] |
Heat Shock
The heat shock response (HSR) is a cell stress response that increases the number of molecular chaperones to combat the negative effects on proteins caused by stressors such as increased temperatures, oxidative stress, and heavy metals. In a normal cell, proteostasis (protein homeostasis) must be maintained because proteins are the main functional units of the cell. Many proteins take on a defined configuration in a process known as protein folding in order to perform their biological functions. If these structures are altered, critical processes could be affected, leading to cell damage or death. The heat shock response can be employed under stress to induce the expression of heat shock proteins (HSP), many of which are molecular chaperones, that help prevent or reverse protein misfolding and provide an environment for proper folding. Protein folding is already challenging due to the crowded intracellular space where aberrant interactions can arise; it becomes more difficult when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Translation (biology)
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 (biology), transcription of DNA to RNA in the cell's nucleus (cell), nucleus. The entire process is called gene expression. In translation, mRNA, messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. The polypeptide later protein folding, folds into an Activation energy, active protein and performs its functions in the Cell (biology), cell. The ribosome facilitates decoding by inducing the binding of Base pair, 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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Small Hairpin RNA
A short hairpin RNA or small hairpin RNA (shRNA/Hairpin Vector) is an artificial RNA molecule with a tight hairpin turn that can be used to silence target gene expression via RNA interference (RNAi). Expression of shRNA in cells is typically accomplished by delivery of plasmids or through viral or bacterial vectors. shRNA is an advantageous mediator of RNAi in that it has a relatively low rate of degradation and turnover. However, it requires use of an expression vector, which has the potential to cause side effects in medicinal applications. The promoter choice is essential to achieve robust shRNA expression. At first, polymerase III promoters such as U6 and H1 were used; however, these promoters lack spatial and temporal control. As such, there has been a shift to using polymerase II promoters, which are inducible, to regulate shRNA expression. Delivery Expression of shRNA in cells can be obtained by delivery of plasmids or through viral or bacterial vectors. Delivery of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Degrees Celsius
The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The degree Celsius (symbol: °C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference or range between two temperatures. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale in 1742. Before being renamed in 1948 to honour Anders Celsius, the unit was called ''centigrade'', from the Latin ''centum'', which means 100, and ''gradus'', which means steps. Most major countries use this scale; the other major scale, Fahrenheit, is still used in the United States, some island territories, and Liberia. The Kelvin scale is of use in the sciences, with representing absolute zero. Since 1743 the Celsius scale has been based on 0 °C for the freezing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hsp20
The heat shock protein Hsp20 family, also known as small heat shock proteins (sHSPs), is a family of heat shock proteins. Prokaryotic and eukaryotic organisms respond to heat shock or other environmental stress by inducing the synthesis of proteins collectively known as heat-shock proteins (hsp). Amongst them is a family of proteins with an average molecular weight of 20 kDa, known as the hsp20 proteins. These seem to act as protein chaperones that can protect other proteins against heat-induced denaturation and aggregation. Hsp20 proteins seem to form large heterooligomeric aggregates. Structurally, this family is characterised by the presence of a conserved C-terminal domain, alpha-crystallin domain, of about 100 residues. Recently, small heat shock proteins (sHSPs) were found in marine viruses (cyanophages). Function and regulation Hsp20, like all heat shock proteins, is in abundance when cells are under stressed conditions. Hsp20 is known to be expressed in many human tiss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Conservation
In evolutionary biology, conserved sequences are identical or similar sequences in nucleic acids ( DNA and RNA) or proteins across species ( orthologous sequences), or within a genome ( paralogous sequences), or between donor and receptor taxa ( xenologous sequences). Conservation indicates that a sequence has been maintained by natural selection. A highly conserved sequence is one that has remained relatively unchanged far back up the phylogenetic tree, and hence far back in geological time. Examples of highly conserved sequences include the RNA components of ribosomes present in all domains of life, the homeobox sequences widespread amongst Eukaryotes, and the tmRNA in Bacteria. The study of sequence conservation overlaps with the fields of genomics, proteomics, evolutionary biology, phylogenetics, bioinformatics and mathematics. History The discovery of the role of DNA in heredity, and observations by Frederick Sanger of variation between animal insulins in 1949, promp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Shock Protein
Heat shock proteins (HSP) are a family of proteins produced by cells in response to exposure to stressful conditions. They were first described in relation to heat shock, but are now known to also be expressed during other stresses including exposure to cold, UV light and during wound healing or tissue remodeling. Many members of this group perform chaperone functions by stabilizing new proteins to ensure correct folding or by helping to refold proteins that were damaged by the cell stress. This increase in expression is transcriptionally regulated. The dramatic upregulation of the heat shock proteins is a key part of the heat shock response and is induced primarily by heat shock factor (HSF). HSPs are found in virtually all living organisms, from bacteria to humans. Heat-shock proteins are named according to their molecular weight. For example, HSP60, Hsp60, Hsp70 and Hsp90 (the most widely studied HSPs) refer to families of heat shock proteins on the order of 60, 70 and 90 ato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
