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Cyano-S1 RNA Motif
The Cyano-S1 RNA motif (originally named the Cyano-30S motif) is a conserved RNA structure present in some species of Cyanobacteria. Cyano-S1 RNAs are consistently found upstream of genes encoding ribosomal protein S1, a subunit of the ribosome. Therefore, they are presumed to be ribosomal protein leaders, i.e., cis-regulatory elements to which the ribosomal protein S1 binds, thereby controlling its expression levels. See also *Cyano-2 RNA motif *Yfr2 *Yfr1 Yfr1 is a Cyanobacterial functional RNA that was identified by a comparative genome based screen for RNAs in cyanobacteria. Further analysis has shown that the RNA is well conserved and highly expressed in cyanobacteria. and is required for gr ... References Ribosomal protein leader {{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] |
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] |
Cis-regulatory Element
''Cis''-regulatory elements (CREs) or ''Cis''-regulatory modules (CRMs) are regions of non-coding DNA which regulate the transcription of neighboring genes. CREs are vital components of genetic regulatory networks, which in turn control morphogenesis, the development of anatomy, and other aspects of embryonic development, studied in evolutionary developmental biology. CREs are found in the vicinity of the genes that they regulate. CREs typically regulate gene transcription by binding to transcription factors. A single transcription factor may bind to many CREs, and hence control the expression of many genes ( pleiotropy). The Latin prefix ''cis'' means "on this side", i.e. on the same molecule of DNA as the gene(s) to be transcribed. CRMs are stretches of DNA, usually 100–1000 DNA base pairs in length, where a number of transcription factors can bind and regulate expression of nearby genes and regulate their transcription rates. They are labeled as ''cis'' because they are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attenuator (genetics)
In genetics, attenuation is a regulatory mechanism for some bacterial operons that results in premature termination of transcription. The canonical example of attenuation used in many introductory genetics textbooks, is ribosome-mediated attenuation of the ''trp'' operon. Ribosome-mediated attenuation of the ''trp'' operon relies on the fact that, in bacteria, transcription and translation proceed simultaneously. Attenuation involves a provisional stop signal (attenuator), located in the DNA segment that corresponds to the leader sequence of mRNA. During attenuation, the ribosome becomes stalled (delayed) in the attenuator region in the mRNA leader. Depending on the metabolic conditions, the attenuator either stops transcription at that point or allows read-through to the structural gene part of the mRNA and synthesis of the appropriate protein. Attenuation is a regulatory feature found throughout Archaea and Bacteria causing premature termination of transcription.Merino E, Yanof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanobacteria
Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blue-green algae, although they are not usually scientifically classified as algae. They appear to have originated in a freshwater or terrestrial environment. Sericytochromatia, the proposed name of the paraphyletic and most basal group, is the ancestor of both the non-photosynthetic group Melainabacteria and the photosynthetic cyanobacteria, also called Oxyphotobacteria. Cyanobacteria use photosynthetic pigments, such as carotenoids, phycobilins, and various forms of chlorophyll, which absorb energy from light. Unlike heterotrophic prokaryotes, cyanobacteria have internal membranes. These are flattened sacs called thylakoids where photosynthesis is performed. Phototrophic eukaryotes such as green plants perform photosynthesis in plast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribosomal Protein S1
Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to form polypeptide chains. Ribosomes consist of two major components: the small and large ribosomal subunits. Each subunit consists of one or more ribosomal RNA (rRNA) molecules and many ribosomal proteins (RPs or r-proteins). The ribosomes and associated molecules are also known as the ''translational apparatus''. Overview The sequence of DNA that encodes the sequence of the amino acids in a protein is transcribed into a messenger RNA chain. Ribosomes bind to messenger RNAs and use their sequences for determining the correct sequence of amino acids to generate a given protein. Amino acids are selected and carried to the ribosome by transfer RNA (tRNA) molecules, which enter the ribosome and bind to the messenger RNA chain via an anti-codon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribosome
Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to form polypeptide chains. Ribosomes consist of two major components: the small and large ribosomal subunits. Each subunit consists of one or more ribosomal RNA (rRNA) molecules and many ribosomal proteins (RPs or r-proteins). The ribosomes and associated molecules are also known as the ''translational apparatus''. Overview The sequence of DNA that encodes the sequence of the amino acids in a protein is transcribed into a messenger RNA chain. Ribosomes bind to messenger RNAs and use their sequences for determining the correct sequence of amino acids to generate a given protein. Amino acids are selected and carried to the ribosome by transfer RNA (tRNA) molecules, which enter the ribosome and bind to the messenger RNA chain via an anti-c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribosomal Protein Leader
A ribosomal protein leader is a mechanism used in cells to control the cellular concentration of a protein that forms a part of the ribosome, and to make sure that the concentration is neither too high nor too low. Ribosomal protein leaders are RNA sequences that are a part of the 5' UTR of mRNAs encoding a ribosomal protein. When cellular concentrations of the ribosomal protein are high, excess protein will bind to the mRNA leader. This binding event can lower gene expression via a number of mechanisms; for example, in the protein-bound state, the RNA could form an intrinsic transcription termination stem-loop. When cellular concentrations of the ribosomal protein are not high, they are occupied in the ribosome, and are not available in significant quantities to bind the mRNA leader. This leads to increased expression of the gene, which leads to the synthesis of more copies of the ribosomal protein. Many examples of ribosomal protein leaders are known in bacteria, including r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cis-regulatory Element
''Cis''-regulatory elements (CREs) or ''Cis''-regulatory modules (CRMs) are regions of non-coding DNA which regulate the transcription of neighboring genes. CREs are vital components of genetic regulatory networks, which in turn control morphogenesis, the development of anatomy, and other aspects of embryonic development, studied in evolutionary developmental biology. CREs are found in the vicinity of the genes that they regulate. CREs typically regulate gene transcription by binding to transcription factors. A single transcription factor may bind to many CREs, and hence control the expression of many genes ( pleiotropy). The Latin prefix ''cis'' means "on this side", i.e. on the same molecule of DNA as the gene(s) to be transcribed. CRMs are stretches of DNA, usually 100–1000 DNA base pairs in length, where a number of transcription factors can bind and regulate expression of nearby genes and regulate their transcription rates. They are labeled as ''cis'' because they are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Expression
Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, protein or non-coding RNA, and ultimately affect a phenotype, as the final effect. These products are often proteins, but in non-protein-coding genes such as transfer RNA (tRNA) and small nuclear RNA (snRNA), the product is a functional non-coding RNA. Gene expression is summarized in the central dogma of molecular biology first formulated by Francis Crick in 1958, further developed in his 1970 article, and expanded by the subsequent discoveries of reverse transcription and RNA replication. The process of gene expression is used by all known life—eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea), and utilized by viruses—to generate the macromolecular machinery for life. In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype, '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyano-2 RNA Motif
The Cyano-2 RNA motif is a conserved RNA structure identified by bioinformatics. Cyano-2 RNAs are found in Cyanobacterial species classified within the genus ''Synechococcus''. Many terminal loops in the two conserved stem-loops contain the nucleotide sequence GCGA, and these sequences might in some cases form stable GNRA tetraloops. Since the two stem-loops are somewhat distant from one another it is possible that they represent two independent non-coding RNAs that are often or always co- transcribed. The region one thousand base pairs upstream of predicted Cyano-2 RNAs is usually devoid of annotated features such as RNA or protein-coding genes. This absence of annotated genes within one thousand base pairs is relatively unusual within bacteria. See also * Yfr1 *Yfr2 Yfr2 (cYanobacterial functional RNA-2 later published as Cyano-1 RNA motif) is a family of non-coding RNAs. Members of the Yrf2 family have been identified in almost all studied species of cyanobacteria. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yfr2
Yfr2 (cYanobacterial functional RNA-2 later published as Cyano-1 RNA motif) is a family of non-coding RNAs. Members of the Yrf2 family have been identified in almost all studied species of cyanobacteria. The family was identified through a bioinformatics screen of published cyanobacterial genomes, having previously been grouped in a family of Yfr2–5. The cyano-1 RNA motif family is essentially a synonym for Yfr2, although Cyano-1 does not include the terminator sequence and Yfr2 does. The function of this ncRNA is unknown, though it has been hypothesised that family members interact with RNA targets through kissing complexes using their highly conserved exposed central consensus element (CSE: IUPAC 5′-RKT SGA AAC WHG GHM ASA M-3′). Earlier studies noted a similarity to quorum sensing ncRNAs in ''Vibrio'' bacteria. The family can be divided into two subgroups, one found in marine cyanobacteria (e.g. the ''Prochlorococcus'' and ''Synechococcus'' genera) and the other from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
