Image operon.png thumb 350px right A typical operon In genetics , an operon is a functioning unit of genomic ... par un op rateur trans title Operon a group of genes with the expression coordinated by an operator ... of this is that the genes contained in the operon are either gene expression expressed together or not at all. Several genes must be both co transcribed and co regulated to define an operon. Citation ... The term operon was first proposed in a short paper in the Proceedings of the French Academy of Science in 1960. From this paper, the so called general theory of the operon was developed. This theory ... is considered a landmark event in the history of molecular biology. The first operon to be described was the lac operon in Escherichia coli . ref name Jacob1960 The 1965 Nobel Prize in Physiology and Medicine ... concerning the operon and virus synthesis. Overview Operons occur primarily in prokaryote s but also ... of eukaryotes including chordate s. An operon is made up of several structural gene s arranged under ... operon, including repressor s, Corepressor genetics corepressor s, and Activator genetics activator s, are not necessarily coded for by that operon. The location and condition of the regulators, promoter ... An operon contains one or more structural gene s which are transcribed into one polycistronic ... transcription. Close to the promoter lies a section of DNA called an operator . The operon ... to the operator and inhibits transcription. Regulatory genes need not be part of the operon ... structure of an operon promoter biology Promoter a nucleotide sequence that enables ... Operator a segment of DNA that a regulator binds to. It is classically defined in the lac operon as a segment between the promoter and the genes of the operon. ref name blewin cite book author ... regulated by the operon. Regulation Control of an operon is a type of gene regulation that enables .... Operon regulation can be either negative or positive by induction or repression. ref name blewin Negative ... more details
lowercase title lac operon The gal operon is a prokaryotic operon , which encodes enzymes necessary for galactose metabolism . The gal operon contains two operator genetics operators , O sub E sub for external and O sub I sub . The former is just before the promoter biology promoter , and the latter is just after the galE gene the first gene in the operon . Repression of gene expression works via binding of repressor molecules to the two operators. These repressors dimerize, creating a loop in the DNA. The loop as well as hindrance from the external operator prevent RNA polymerase from binding to the promoter, and thus prevent transcription genetics transcription . The gal operon of E. coli consists of 3 structural genes galE epimerase , galT galactose transferase , and galK galactokinase , which are transcribed from two overlapping promoters PG1 and PG2 upstream from galE. Regulation of the operon is complex since the GalE product, an epimerase that converts UDP galactose into UDP glucose, is required for the formation of UDP glucose for cell wall biosynthesis even when cells are not using galactose as a carbon energy source. The gal operon is controlled by CRP cAMP as for the lac operon. CRP cAMP binds to 35 region promoting transcription from PG1 but inhibiting transcription from PG2. When cells are grown in glucose, basal level transcription occurs from PG2. The unlinked galR gene encodes the repressor for this system. A tetrameric GalR repressor binds to 2 operators, one located at 55 and one located at 60 relative to the PG1 start site. Looping of the DNA blocks the access of RNA polymerase to promoters and or inhibits formation of the open complex. When GalR binds as a dimer to the 60 site only, promoter PG2 is activated, not repressed, allowing basal levels of GalE to be produced. In this state promoter PG1 is inactivated through interactions with the alpha subunit of RNA polymerase molecular biology stub genetics stub Transcription Category Gene expression ... more details
Image Trpoperon.svg thumb 400px Structure of the trp operon. Trp operon is an operon a group of genes ... . The Trp operon is present in many bacteria , but was first characterized in Escherichia coli . It is regulated .... Discovered in 1953 by Jacques Monod and colleagues, the trp operon in E. coli was the first repressible operon to be discovered. While the lac operon can be activated by a chemical allolactose , the tryptophan Trp operon is inhibited by a chemical tryptophan . This operon contains five structural ... to the protein synthesized by the repressor gene trp R that binds to the operator. In the lac operon, allolactose binds to the repressor protein, allowing gene transcription, while in the trp operon, tryptophan ..., repression is that of RNA polymerase transcribing the genes in the operon. Also unlike the lac operon, the trp operon contains a leader peptide and an attenuator genetics attenuator sequence which ... expression. Within the operon s regulatory sequence, the operator biology operator is blocked by the repressor ... feedback mechanism. The repressor for the trp operon is produced upstream by the trpR gene, which ... RNA polymerase from binding to and transcribing the operon, so tryptophan is not produced from its precursor ... the operator region, so transcription is not inhibited by the repressor. Attenuation Image Trp operon attenuation.svg thumb 400px Mechanism of transcriptional attenuation of the trp operon. Attenuator genetics Attenuation is a second mechanism of negative feedback in the trp operon. While the TrpR ... sequence. This allows the process of translation to directly affect transcription of the operon. At the beginning of the transcribed genes of the trp operon is a sequence of 140 nucleotides termed the leader ... RNA polymerase will disassociate from the DNA and transcription of the structural genes of the operon ... hairpin. RNA polymerase is free to continue transcribing the entire operon. If tryptophan levels ... which terminates transcription. The end result is that the operon will be transcribed only when tryptophan ... more details
lowercase title Lac operon The lac operon is an operon required for the transport and metabolism of lactose ... gene s, lacZ, lacY and lacA. The lac operon is regulated by several factors including the availability of glucose and of lactose . Gene regulation of the lac operon was the first complex genetic regulatory ... regulation . Image lac operon1.png Layout of the lac operon. In its natural environment, the lac operon ... readily available energy source available such as glucose. The lac operon uses a two ... growth patterns are known as xyl operon and ara operon ara operon , etc. Structure of the lac operon Image Lactose etc.png thumb 300px Structure of lactose and the products of its cleavage. The lac operon consists of three structural gene s, and a promoter biology promoter , a terminator genetics .... The lac genes are organized into an operon that is, they are oriented in the same direction immediately ... into mRNA. The DNA sequence of the E. coli lac operon , the lacZYA mRNA , and the lacI genes are available ... in the absence of lactose. The lacI gene coding for the repressor lies nearby the lac operon and is always ... galactose and glucose. The diagram below summarizes these statements. Image Lac operon 2010 21 01.png thumb center 550px lac operon in detail Genetic nomenclature Three letter abbreviations are used ... of lactose derivatives or analogs have been described that are useful for work with the lac operon ... of the lac operon for physiological work. ref Stryer IPTG binds to repressor and inactivates it, but is not a substrate ... and is the inducer of the lac operon. Lactose is galactose 1 4 glucose, whereas allolactose ... of a second, functional aeroplane. To analyze regulatory mutants of the lac operon, Jacob developed ... diffuse in the cell. The copy of the lac operon adjacent to the defective lacI gene is effectively shut ..., only the copy of the lac operon that is adjacent to the mutant operator is expressed ... only the copy of the operon which is immediately adjacent to it. This explanation is misleading ... more details
Rfam box acc RF00506 description Threonine operon leader abbreviation Thr leader avg length 116.00 avg identity 72.00 type Cis reg leader se Bateman A ss Published PMID 6186194 release 10.0 The threonine operon leader is an cis regulatory element RNA element . Threonine is one of at least 6 amino acid operon s are known to be regulated by Attenuator genetics attenuation . ref name kolter 1982 cite journal last Kolter first R coauthors Yanofsky C year 1982 title Attenuation in amino acid biosynthetic operons journal Annu Rev Genet volume 16 pages 113&ndash 134 pmid 6186194 doi 10.1146 annurev.ge.16.120182.000553 ref In each a leader sequence of 150 200 bp is found upstream of the first gene in the operon. This leader sequence can assume two different secondary structures known as the terminator and the anti terminator structure. In each case the leader also codes for very short peptide sequence that is rich in the end product amino acid of the operon. The terminator structure is recognised as a termination signal for RNA polymerase and the operon is not transcribed. This structure forms when the cell has an excess of the regulatory amino acid and ribosome movement over the leader transcript is not impeded. ref name kolter 1982 When there is a deficiency of the charged tRNA of the regulatory amino acid the ribosome translating the leader peptide stalls and the antiterminator structure can form. This allows RNA polymerase to transcribe the operon. ref name kolter 1982 References reflist 1 External links Rfam id RF00506 name Threonine operon leader Category Cis regulatory RNA elements molecular cell biology stub ... more details
The L arabinose operon of the model organism model bacterium Escherichia coli has been a focus for research in molecular biology for over 40 years, and has been investigated extensively at the Genetics genetic , biochemical , physiological , and biophysical levels. It is controlled by a dual positive and negative system. There are 3 structural genes araB , araA , and araD . They encode the metabolic enzymes for breaking down the monosaccharide sugar arabinose into xylulose D xylulose 5 phosphate , which is then metabolised via the pentose phosphate pathway . The initiator region, containing an operator site as well as a promoter, is called araI the last letter of araI is an uppercase letter i . Near this site lies the araC gene, which encodes a repressor protein. The AraC protein binds to initiator region araI . class wikitable Metabolism of arabinose in E. coli Substrate Protein s Function Reversible Product L arabinose AraA isomerase yes L ribulose L ribulose AraB ribulokinase no L ribulose phosphate L ribulose phosphate AraD epimerase yes D xylulose phosphate Activation If arabinose is present, it builds a complex AraC arabinose br This complex is needed for RNA polymerase to bind to the promoter and transcribe the ara operon. Also for activation the binding of another structure to araI is needed CAP cyclic AMP br So the activation depends on the presence of arabinose and cAMP. Repression If arabinose is absent, the AraC protein assumes a different conformation. In this conformation the AraC protein binds to the araI DNA region as well as to the ara0 DNA region. This causes the DNA to form a loop, preventing transcription of the downstream ara operon elements. Sequence of the Operon araC araO araI araB araA araD See also The lac operon is another operon in E. coli that has ... last first Robert Schleif authorlink coauthors title Regulation of the L arabinose operon of Escherichia ... id Operon ara nl Arabinose operon ... more details
Rfam box acc RF00514 description Histidine operon leader abbreviation His leader avg length 126.60 avg identity 69.00 type Cis reg leader se Bateman A ss Published PMID 6186194 release 10.0 The Histidine operon leader is an cis regulatory element RNA element found in the bacteria l histidine operon . At least 6 amino acid operons are known to be regulated by attenuation . ref name pmid6186194 cite journal author Kolter R, Yanofsky C title Attenuation in amino acid biosynthetic operons journal Annu. Rev. Genet. volume 16 issue pages 113 34 year 1982 pmid 6186194 doi 10.1146 annurev.ge.16.120182.000553 ref In each a leader sequence of 150 200 bp is found upstream of the first gene in the operon. This leader sequence can assume two different secondary structures known as the terminator and the anti terminator structure. In each case the leader also codes for very short peptide sequence that is rich in the end product amino acid of the operon. The terminator structure is recognised as a termination signal for RNA polymerase and the operon is not transcribed. This structure forms when the cell has an excess of the regulatory amino acid and ribosome movement over the leader transcript is not impeded. ref name pmid6186194 When there is a deficiency of the charged tRNA of the regulatory amino acid the ribosome translating the leader peptide stalls and the antiterminator structure can form. This allows RNA polymerase to transcribe the operon. ref name pmid6186194 References reflist 1 cite journal author Chan CL, Landick R title Dissection of the his leader pause site by base substitution reveals a multipartite signal that includes a pause RNA hairpin journal J. Mol. Biol. volume 233 issue 1 pages 25 42 year 1993 pmid 8377190 doi 10.1006 jmbi.1993.1482 cite journal author Chan CL, Landick R title The Salmonella typhimurium his operon leader region contains an RNA hairpin dependent ... links Rfam id RF00514 name Histidine operon leader Category Cis regulatory RNA elements molecular ... more details
Rfam box acc RF00513 description Tryptophan operon leader abbreviation Trp leader avg length 98.40 avg identity 65.00 type Cis reg leader se Bateman A ss Published PMID 6186194 release 10.0 The Tryptophan operon leader is an cis regulatory element RNA element found at the 5 of some bacterial Trp operon tryptophan operons . The leader sequence can assume two different secondary structures known as the terminator and the anti terminator structure. The leader also codes for very short peptide sequence that is rich in Tryptophan. The terminator structure is recognised as a termination signal for RNA polymerase and the operon is not transcribed. This structure forms when the cell has an excess of tryptophan and ribosome movement over the leader transcript is not impeded. ref cite journal last Kolter first R coauthors Yanofsky C year 1982 title Attenuation in amino acid biosynthetic operons journal Annu Rev Genet volume 16 pages 113 134 pmid 6186194 doi 10.1146 annurev.ge.16.120182.000553 ref When there is a deficiency of the charged tryptophanyl tRNA the ribosome translating the leader peptide stalls and the antiterminator structure can form. This allows RNA polymerase to transcribe the operon. At least 6 different amino acid operons are known to be regulated by this attenuation. References Reflist External links Rfam id RF00513 name Tryptophan operon leader Category Cis regulatory RNA elements molecular cell biology stub ... more details
Rfam box acc RF00512 description Leucine operon leader abbreviation Leu leader avg length 145.00 avg identity 75.00 type Cis reg leader se Bateman A ss Published PMID 6186194 release 10.0 The Leucine operon leader is an cis regulatory element RNA element found upstream of the first gene in the Leucine biosynthetic operon . ref name pmid6186194 cite journal author Kolter R, Yanofsky C title Attenuation in amino acid biosynthetic operons journal Annu. Rev. Genet. volume 16 issue pages 113 34 year 1982 pmid 6186194 doi 10.1146 annurev.ge.16.120182.000553 issn ref The leader sequence can assume two different secondary structures known as the terminator and the anti terminator structure. The leader also codes for very short peptide sequence that is rich in leucine amino acid. The terminator structure is recognised as a termination signal for RNA polymerase and the operon is not transcribed. This structure forms when the cell has an excess of leucine and ribosome movement over the leader transcript is not impeded. ref name pmid6186194 When there is a deficiency of the charged leucyl tRNA the ribosome translation translating the leader peptide stalls and the antiterminator structure can form. This allows RNA polymerase to transcribe the operon. ref name pmid6186194 At least 6 amino acid operons are known to be regulated by attenuation. ref name pmid6186194 References reflist 1 External links Rfam id RF00512 name Leucine operon leader Category Cis regulatory RNA elements molecular cell biology stub ... more details
Orphan date February 2009 Rfam box acc RF00140 description Alpha operon ribosome binding site abbreviation Alpha RBS avg length 91.10 avg identity 60.00 type Cis reg se Griffiths Jones SR ss Published PMID 11504736 release 10.0 The alpha operon ribosome binding site in bacteria is surrounded by this complex pseudoknot ted RNA structure. Translation of the mRNA produces 4 ribosomal protein products, one of which S4 acts as a translational repressor by binding to the nested pseudoknot region. The mechanism of repression is thought to involve a conformational switch in the pseudoknot region and ribosome entrapment. ref cite journal last Schlax first PJ coauthors Xavier KA, Gluick TC, Draper DE year 2001 title Translational repression of the Escherichia coli alpha operon mRNA importance of an mRNA conformational switch and a ternary entrapment complex journal J Biol Chem volume 276 pages 38494&ndash 38501 pmid 11504736 doi 10.1074 jbc.M106934200 issue 42 ref References reflist 1 External links Rfam id RF00140 name Alpha operon ribosome binding site Category Cis regulatory RNA elements molecular cell biology stub ... more details
LACA may refer to lac operon Structure of the operon lacA , a structural gene in the lac operon. Luxembourg Approach Controllers Association , the air traffic control in Luxembourg. disambig ... more details
In genetics , an operator is a segment of DNA to which a repressor binds. It is classically defined in the lac operon lac operon as a segment between the promoter biology promoter and the genes of the operon . In the case of a repressor , the repressor protein physically obstructs the RNA polymerase from transcription genetics transcribing the genes . An inducer protein can displace a repressor protein from the operator site DNA , which results in an uninhibited operon . Category Gene expression de Operator Genetik it Operatore biologia ja ... more details
For the spasmolytic Modulon Modulon drug Unreferenced date December 2009 Orphan date February 2009 Context date October 2009 An operon is a set of genes controlled by a single DNA binding protein. Multiple operons controlled by the same repressor are grouped together as a regulon . A modulon is a regulon concerned with multiple pathways or functions, in which operons may be under individual controls as well as common, pleiotropic regulatory protein. For example the CAP modulon contains all regulons operons, such as the lac operon and ara regulon, that are regulated by Catabolite Activator Protein CAP Cyclic adenosine monophosphate cAMP , but each operon has other regulators as well. Category Gene expression ... more details
AraC may refer to The araC gene and araC protein, components of the L arabinose operon in the genome of the bacterium Escherichia coli Cytarabine , a chemotherapy chemotherapeutic agent commonly used in the treatment of leukemia s and lymphoma s disambig ... more details
galactoside permease is a cell membrane membrane bound Membrane transport protein transport protein that active transport pumps lactose into the cell biology cell . See also lac operon permease galactoside External links MeshName Permease, beta galactoside Category Transport proteins enzyme stub ... more details
For Polar effect in Chemistry Polar effect Unreferenced date November 2006 Polar effect in genetics occurs when the mutation of one gene prevents other genes in the same operon from being transcribed. Category Mutation Genetics stub ... more details
Unreferenced date November 2006 orphan date November 2009 In cell biology a stimulon is a collection of genes which may be in operon s and regulon s under regulation by the same stimulus. This term is generally used for prokaryote prokaryotic systems, for example quorum sensing in bacteria . Category Cell signaling Molecular cell biology stub ... more details
orphan date September 2010 A long range pseudoknot is a pseudoknot containing a long loop region, and may be a mechanism of translational control. A long range pseudoknot is thought to negatively regulate the translation of the IF3 L35 L20 operon in E. coli . This operon encodes the translation factor 3 IF3 and ribosomal proteins L35 and L20. In this example, the RNA RNA interaction occurs between nucleotides separated by a 300 nucleotide loop region. ref cite journal title A long range RNA RNA interaction forms a pseudoknot required for translational control of the IF3 L35 L20 ribosomal protein operon in Escherichia coli. journal EMBO J year 1996 first C last Chiaruttini coauthors M Milet, M Springer volume 15 16 issue 16 pages 4402 13 pmid 8861967 url http www.ncbi.nlm.nih.gov pubmed 8861967?dopt Abstract pmc 452164 ref A long range pseudoknot is also believed to be required for the activity of the Neurospora VS ribozyme . ref cite journal title A long range pseudoknot is required for activity of the Neurospora VS ribozyme. journal EMBO J year 1996 first T last Rastogi coauthors T L Beattie, J E Olive, and R A Collins volume 15 11 issue 11 pages 2820 25 pmid 8654379 pmc 450219 ref References Reflist Category Non coding RNA ... more details
transcribed . Image Lac operon.png thumb center 550px lac operon in detail See also Glossary of gene expression terms Operon Regulation of gene expression Transcription factor DEFAULTSORT Activator ... more details
operon An example is the trp operon trp gene in bacteria . When there is a high level of tryptophan ... sequence, which is located between the mRNA leader sequence 5 Untranslated Region UTR and trp operon ... of the trp operon. Since the protein coding genes are not transcribed due to rho independent termination ... not signal termination of transcription. Therefore the rest of the operon will be transcribed and translated ... peptide, but is not part of the trp operon gene sequence. The attenuator allows more time for the attenuator ... operon. While the TrpR repressor decreases transcription by a factor of 70, attenuation can further ... to directly affect transcription of the operon. At the beginning of the transcribed genes of the trp operon is a sequence of 140 nucleotides termed the leader transcript trpL . This transcript ... genes of the operon will not occur. Part of the leader transcript codes for a short polypeptide of 14 ... transcribing the entire operon. If tryptophan levels in the cell are high, the ribosome will translate ... is that the operon will be transcribed only when tryptophan is unavailable for the ribosome, while ... in the trp operon of E. coli . The first observation was linked to two separate scientific facts. Mutations which knocked out the trp R repressor gene still showed some regulation of the trp operon these mutants were not fully induced repressed by tryptophan . The total range of trp operon regulation ... by the absence or presence of trp. When the sequence of the beginning of the trp operon was determined ... below was observed from the sequence of the trp operon. First, Yanofsky observed that the ORF contained ... . Mechanism in the trp operon The proposed mechanism of how this mRNA secondary structure and the trp ... the expression of genes in a biosynthetic operon lead to its rediscovery in a wide variety of such operons for which repressors had never been discovered. For example class wikitable Operon Leader peptide Article Histidine MTRVQFKHHHHHHHPD stop Histidine operon leader Threonine MKRISTTITTTITITTGNGAG ... more details
Image gattrimerB IPTG.jpg thumb 310px GAT in complex with CoA and two molecules active site of IPTG viewed perpendicular to the molecular threefold axis of the enzyme galactoside transacetylase is an enzyme that transfers an acetyl group from acetyl CoA to galactoside s. Coded by the gene lacA in the lac operon of Escherichia coli . ref cite journal journal Structure year 2002 month April volume 10 issue 4 pages 581 8 title Structure of the lac operon galactoside acetyltransferase author Wang XG coauthors Olsen LR Roderick SL. pmid 11937062 doi 10.1016 S0969 2126 02 00741 4 ref Its precise function as part of the lac operon is not understood currently. ref cite journal journal C R Biol. year 2005 month June volume 328 issue 6 pages 568 75 title The lac operon galactoside acetyltransferase author Roderick SL. pmid 15950163 doi 10.1016 j.crvi.2005.03.005 ref The kinetics of the enzyme were worked out in 1995. ref cite journal author A. Lewendon coauthors J. Ellis, W.V. Shaw year 1995 title Structural and Mechanistic Studies of Galactoside Acetyltransferase, the Escherichia coli LacA Gene Product journal J. Biol. Chem. volume 270 pages 26326 31. pmid 7592843 doi 10.1074 jbc.270.44.26326 issue 44 ref See also transacetylase References references External links MeshName galactoside acetyltransferase EC number 2.3.1.18 Acyltransferases Category Transferases Category EC 2.3.1 transferase stub fr B ta galactoside transac tylase ... more details
Orphan date December 2010 File HopC RNA.svg right frame Consensus secondary structure of hopC RNAs. This figure is adapted from a previous publication. ref name Weinberg2010 The hopC RNA motif is a predicted cis regulatory element identified by a bioinformatics bioinformatic screen for conserved RNA secondary structure s. ref name Weinberg2010 cite journal author Weinberg Z, Wang JX, Bogue J, et al. title Comparative genomics reveals 104 candidate structured RNAs from bacteria, archaea and their metagenomes journal Genome Biol volume 11 issue 3 pages R31 year 2010 month March pmid 20230605 doi 10.1186 gb 2010 11 3 r31 url pmc 2864571 ref hopC RNAs are exclusively found within bacteria classified within the genus Helicobacter , some of which are human pathogen s that infect the stomach and can cause peptic ulcer ulcers . hopC RNAs are found upstream of an operon of two genes called hopC and hopB also called alpa and alpB . Experiments on the start of transcription genetics transcription for the hopCB operon ref name McGowan indicate that hopC RNAs lie within the 5 untranslated region of this operon. The hopCB operon is induced to higher levels of expression in response to low pH . ref name McGowan This fits in with data that HopCB is involved in binding to human epithelial cells, ref cite journal author Odenbreit S, Faller G, Haas R title Role of the alpAB proteins and lipopolysaccharide in adhesion of Helicobacter pylori to human gastric tissue journal Int. J. Med. Microbiol. volume 292 issue 3 4 pages 247 56 year 2002 month September pmid 12398215 doi url ref which is presumably something that the bacteria do during infection of the low pH environment of the stomach. Previous work suggested that a repeat of 13 thymidine nucleotide s might be involved in regulating the abundance of the hopCB operon. ref name McGowan cite journal author McGowan CC, Necheva AS, Forsyth MH, Cover TL, Blaser MJ title Promoter analysis of Helicobacter pylori genes with enhanced expressio ... more details
Orphan date February 2009 Rfam box acc RF00391 description RtT RNA abbreviation RtT avg length 127.60 avg identity 57.00 type Cis reg se PMID 1840671 ss Published PMID 1840671 Moxon SJ release 10.0 The RtT RNA is a cis regulatory element RNA element that is released from the tyrT operon of Escherichia coli . The exact function of RtT is unknown although it is thought that it may be involved in changing the cellular response in relation to amino acid starvation. ref cite journal last Bosl first M coauthors Kersten H year 1991 title A novel RNA product of the tyrT operon of Escherichia coli journal Nucleic Acids Res volume 19 pages 5863&ndash 5870 pmid 1840671 doi 10.1093 nar 19.21.5863 issue 21 pmc 329039 ref References reflist 1 External links Rfam id RF00391 name RtT RNA Category Cis regulatory RNA elements molecular cell biology stub ... more details
The IscR stability element is a conservation genetics conserved secondary structure found in the intergenic regions of iscRSUA polycistronic mRNA. This secondary structure prevents the degradation of the iscR mRNA . The iscRSUA operon encodes for the protein proteins required in iron sulfur cluster biosynthesis where the gene expression expression of this operon is regulated by RyhB RNA RhyB and iscR, a transcription repressor. ref name pmid12975324 Cite pmid 12975324 ref ref name pmid16199566 Cite pmid 16199566 ref ref name pmid12446632 Cite pmid 12446632 ref Under sufficient iron conditions RhyB binds to iscRSUA mRNA and promotes the degradation of the mRNA located downstream of iscR. Scanning the intergenic regions of this polycistronic mRNA and using Mfold software a secondary structure was predicted within the intergenic region between iscR and iscS and later confirmed by lead acetate probing. ref name pmid19407815 Cite pmid 19407815 ref Mutant Mutations that disrupt this secondary structure resulted in the degradation of iscR mRNA after RhyB binding. 3 Rapid Amplification of cDNA Ends RACE analysis of the iscR mRNA fragment identified the intergenic RNA at the 3 end. These results suggest that this intergenic RNA element acts as a iscR mRNA stability element by protecting iscR from exonuclease degradation. References reflist Category RNA Category Gene expression Category Non coding RNA ... more details
wiktionarypar regulon Regulon may refer to TOC right Science, technology, and mathematics In cell biology and genetics , a regulon is a collection of genes or operon operons under regulation by the same regulatory protein . This term is generally used for prokaryote prokaryotic systems, for example quorum sensing in bacteria . It is a group of operons genes spread around the chromosome but controlled by a common factor or stimulus. Multiple regulons can form a modulon . Regulon, Inc. biopharmaceutical company based in Athens, Greece and in Mountain View, CA USA http regulon.org http regulon.org Official Site Other uses Regulon was the sad, homosexual, emperor of the universe portrayed in the novel Regulator of the Universe , by the underground Japanese author Pen Nam. disambig ... more details
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