Target type: biologicalprocess
A negative regulation of gene expression mechanism by which bacteria and archae can direct RNA polymerase to prematurely terminate transcription in response to a specific metabolic signal. [PMID:12210530, PMID:15851059, PMID:7007895]
Transcriptional attenuation is a regulatory mechanism that controls gene expression at the level of transcription termination. It occurs in prokaryotes and involves premature termination of transcription before the gene of interest is fully transcribed. The process is often used to regulate the expression of genes involved in amino acid biosynthesis. Here’s a detailed description of how it works:
1. **Leader Sequence:** The DNA sequence upstream of the gene of interest contains a regulatory region known as the leader sequence. This sequence has two important features:
* **Ribosome Binding Site (RBS):** A sequence that allows ribosomes to bind and initiate translation.
* **Attenuator Region:** A region containing a series of short sequences that can form alternative stem-loop structures.
2. **Transcription and Translation Coupling:** In prokaryotes, transcription and translation are coupled processes. As the RNA polymerase transcribes the leader sequence, ribosomes bind to the RBS and begin translating the leader mRNA.
3. **Alternative Stem-Loop Structures:** The attenuator region of the leader sequence contains four short sequences that can form alternative stem-loop structures. These structures are influenced by the presence or absence of the amino acid that the gene is responsible for producing.
4. **Attenuation Mechanism:**
* **Abundant Amino Acid:** If the amino acid is abundant, ribosomes translate through the leader sequence without pausing. This allows the formation of a stem-loop structure that terminates transcription prematurely.
* **Limited Amino Acid:** If the amino acid is scarce, ribosomes stall at a specific codon within the leader sequence. This stalling allows a different stem-loop structure to form, which does not terminate transcription.
5. **Transcription Termination:** The formation of the terminator stem-loop structure signals RNA polymerase to dissociate from the DNA template, preventing further transcription of the gene.
In essence, transcriptional attenuation acts as a feedback mechanism. When the amino acid is abundant, transcription is terminated, preventing the synthesis of more of that amino acid. When the amino acid is scarce, transcription continues, allowing for the production of more of the amino acid. This process ensures that cells only produce the necessary amounts of specific amino acids, preventing wasteful overproduction.'
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Protein | Definition | Taxonomy |
---|---|---|
50S ribosomal protein L4 | A large ribosomal subunit protein uL4 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P60723] | Escherichia coli K-12 |
Compound | Definition | Classes | Roles |
---|---|---|---|
chloramphenicol | Amphenicol: Chloramphenicol and its derivatives. | C-nitro compound; carboxamide; diol; organochlorine compound | antibacterial drug; antimicrobial agent; Escherichia coli metabolite; geroprotector; Mycoplasma genitalium metabolite; protein synthesis inhibitor |
framycetin | framycetin : A tetracyclic antibacterial agent derived from neomycin, being a glycoside ester of neamine and neobiosamine B. Framycetin: A component of NEOMYCIN that is produced by Streptomyces fradiae. On hydrolysis it yields neamine and neobiosamine B. (From Merck Index, 11th ed) | aminoglycoside | allergen; antibacterial drug; Escherichia coli metabolite |
erythromycin | erythromycin : Any of several wide-spectrum macrolide antibiotics obtained from actinomycete Saccharopolyspora erythraea (formerly known as Streptomyces erythraeus). erythromycin A : An erythromycin that consists of erythronolide A having 2,6-dideoxy-3-C-methyl-3-O-methyl-alpha-L-ribo-hexopyranosyl and 3,4,6-trideoxy-3-(dimethylamino)-beta-D-xylo-hexopyranosyl residues attahced at positions 4 and 6 respectively. Erythromycin: A bacteriostatic antibiotic macrolide produced by Streptomyces erythreus. Erythromycin A is considered its major active component. In sensitive organisms, it inhibits protein synthesis by binding to 50S ribosomal subunits. This binding process inhibits peptidyl transferase activity and interferes with translocation of amino acids during translation and assembly of proteins. | cyclic ketone; erythromycin | |
neamine | neamine : 2-Deoxy-D-streptamine glycosylated at the 4-oxygen with a 6-amino-alpha-D-glucosaminyl group. neamine: fragment of NEOMYCIN B; structure in first source | 2,6-dideoxy-alpha-D-glucoside; aminoglycoside | antibacterial agent |
florfenicol | florfenicol : A carboxamide that is the N-dichloroacetyl derivative of (1R,2S)-2-amino-3-fluoro-1-[4-(methanesulfonyl)phenyl]propan-1-ol. A synthetic veterinary antibiotic that is used for treatment of bovine respiratory disease and foot rot; also used in aquaculture. florfenicol: structure given in first source | organochlorine compound; organofluorine compound; secondary alcohol; secondary carboxamide; sulfone | antimicrobial agent |
antibiotic g 418 | antibiotic G 418: from Micromonospora rhodorangea | ||
paromomycin | paromomycin : An amino cyclitol glycoside that is the 1-O-(2-amino-2-deoxy-alpha-D-glucopyranoside) and the 3-O-(2,6-diamino-2,6-dideoxy-beta-L-idopyranosyl)-beta-D-ribofuranoside of 4,6-diamino-2,3-dihydroxycyclohexane (the 1R,2R,3S,4R,6S diastereoisomer). It is obtained from various Streptomyces species. A broad-spectrum antibiotic, it is used (generally as the sulfate salt) for the treatment of acute and chronic intestinal protozoal infections, but is not effective for extraintestinal protozoal infections. It is also used as a therapeutic against visceral leishmaniasis. Paromomycin: An aminoglycoside antibacterial and antiprotozoal agent produced by species of STREPTOMYCES. | amino cyclitol glycoside; aminoglycoside antibiotic | anthelminthic drug; antibacterial drug; antiparasitic agent; antiprotozoal drug |
puromycin | puromycins | antiinfective agent; antimicrobial agent; antineoplastic agent; EC 3.4.11.14 (cytosol alanyl aminopeptidase) inhibitor; EC 3.4.14.2 (dipeptidyl-peptidase II) inhibitor; nucleoside antibiotic; protein synthesis inhibitor | |
netilmicin | Netilmicin: Semisynthetic 1-N-ethyl derivative of SISOMYCIN, an aminoglycoside antibiotic with action similar to gentamicin, but less ear and kidney toxicity. | ||
linezolid | acetamides; morpholines; organofluorine compound; oxazolidinone | antibacterial drug; protein synthesis inhibitor | |
zithromax | azithromycin : A macrolide antibiotic useful for the treatment of bacterial infections. Azithromycin: A semi-synthetic macrolide antibiotic structurally related to ERYTHROMYCIN. It has been used in the treatment of Mycobacterium avium intracellulare infections, toxoplasmosis, and cryptosporidiosis. | macrolide antibiotic | antibacterial drug; environmental contaminant; xenobiotic |
tiamulin | tiamulin : A carbotricyclic compound that is pleuromutilin in which the hydroxyacetate group is replaced by a 2-{[2-(diethylamino)ethyl]sulfanyl}acetate group. An antibacterial drug, tiamulin is used in veterinary medicine (generally as its hydrogen fumarate salt) for the treatment of swine dysentery caused by Serpulina hyodysenteriae. tiamulin: 81723 HFU and tiamutin are for fumarate salt; prevents senescence in ascomycete; pleuromutilin derivative; RN given refers to ((3aS-(3aalpha,4beta,5alpha,6alpha,8beta,9alpha,9abeta,10S*))-isomer | carbotricyclic compound; carboxylic ester; cyclic ketone; organic sulfide; secondary alcohol; semisynthetic derivative; tertiary amino compound; tetracyclic diterpenoid | antibacterial drug |
hmr 3647 | |||
josamycin | acetate ester; aldehyde; disaccharide derivative; glycoside; macrolide antibiotic; tertiary alcohol; tertiary amino compound | antibacterial drug; metabolite | |
albocycline | albocycline: macrolide antibiotic isolated from Streptomyces bruneogriseus nov. sp. MCRL-0129; specifically anti-staphylococcal, including antibiotic-resistant strains; structure | macrolide | |
evernimicin | |||
gentamicin sulfate | |||
pristinamycin iib | virginiamycin M2: structure in first source | ||
cem 101 | solithromycin: an antibacterial fluoroketolide; structure in first source | ||
tetracycline | tetracycline : A broad-spectrum polyketide antibiotic produced by the Streptomyces genus of actinobacteria. Tetracycline: A naphthacene antibiotic that inhibits AMINO ACYL TRNA binding during protein synthesis. | ||
eravacycline | eravacycline: has antibacterial activity | tetracyclines |