Lactose promoter, tryptophan
Promoter), Tac (hybrid promoter of lactose and tryptophan), lPL (l phage
Left promoter), T7 phage promoter, etc.
(1)Lac promoter: It comes from E.coli.
Lactose operon
It's a DNA molecule
The last targeted nucleotide sequence consists of a repressor gene (LacI), a promoter gene (P), an operator gene (O) and gene structures encoding three enzymes related to lactose utilization. Lac promoter is catabolized.
Positive regulation of system and negative regulation of repressor. Positive regulation activates the promoter through CAP (catabolite gene activation protein) factor and cAMP, which promotes transcription. Negative regulation refers to the regulation of genes to produce LacZ repressor protein, which can combine with the manipulation genes to prevent transcription. Lactose and some analogues, such as IPTG, can form a complex with repressor protein, change its configuration, and cannot combine with O gene, thus relieving this repression and inducing transcription.
(2)trp promoter: trp operon from E.coli, whose repressor protein must be bound to tryptophan to be active. When tryptophan is deficient, the promoter begins to transcribe. When tryptophan is abundant, transcription stops. B- indole
acrylic acid
It can competitively inhibit the combination of tryptophan and repressor protein, inactivate repressor protein and promote the transcription of trp promoter.
(3)Tac promoter: Tac promoter is a group of hybrid promoters artificially constructed by Lac and trp promoters, which is negatively regulated by Lac repressor protein and has stronger startup ability than Lac and trp. Among them, Tac 1 consists of -35 region of Trp promoter plus a synthetic 46 bp DNA fragment (including Pribnow box) and Lac operon gene, and Tac 12 consists of -35 region of Trp promoter and-10 region of Lac promoter, plus Lac operon and the operon gene in SD sequence. Tac promoter was induced by IPTG.
(4)lPL promoter: Derived from the early left transcription promoter of L phage, it is a strong promoter with activity about 1 1 times higher than Trp promoter. LPL promoter is controlled by temperature-sensitive repressor cIts857. At low temperature (30℃), cIts857 repressor protein can inhibit the transcription of PL promoter. At high temperature (45℃), cIts857 protein was inactivated, repression was released, and PL promoter was transcribed. Because of cIts857, the system is especially suitable for expressing gene products that are toxic to Escherichia coli. The disadvantage is that temperature conversion can induce not only PL promoter, but also heat shock genes, some of which encode protease.
. This contradiction can be alleviated if L phage cI+ lysogenic bacteria are used and induced by mitomycin C or nalidixic acid.
(5)T7 phage promoter: It is a promoter from T7 phage with high specificity.
Only T7RNA polymerase.
Can be started, so the cloned gene can be expressed independently. The efficiency of T7RNA polymerase is about 5 times higher than that of Escherichia coli RNA polymerase. It can make the plasmid transcribe continuously along the template for several weeks, and there are many exogenous terminators.
It can not effectively terminate its sequence, so it can transcribe some sequences that Escherichia coli RNA polymerase can not effectively transcribe. This system can efficiently express genes that cannot be effectively expressed by other systems. However, it should be noted that when using this promoter, the host must contain T7RNA polymerase. The application of T7 phage expression system requires two conditions: one is to have T7 phage RNA polymerase, which can be produced by infected L phage or by gene copy inserted into Escherichia coli chromosome; The second is a vector with T7 phage promoter upstream of the gene to be expressed.
Answer on 2011-12-09.
Agree 5
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What is the upstream promoter element of eukaryotes?
There are three types of eukaryotic promoters, which are transcribed by RNA polymerase ⅰ, ⅱ and ⅲ respectively. ⅰ (type ⅰ promoter: only controls the transcription of rRNA precursor gene, and the transcript is cut and processed to generate various mature rRNA. Class I promoter consists of two conserved sequences: the core promoter, located near the transcription start point, from -45 to+20; Upstream control element (UCE): located between-180 and-107; RNA polymerase I needs two factors to participate in its transcription: the polypeptide chain with ubf 1:m of 97000 binds to the GC-rich regions of the above two parts; 1 TBP, namely TATA binding protein (TBP); SL 1: A tetrameric protein containing three different transcription cofactors TAFⅰ Ⅰ: Under the mediation of SL 1, RNA polymerase I binds to the transcription origin and starts transcription. Class Ⅱ promoters: Class Ⅱ promoters are involved in controlling the expression of many genes encoding protein. This kind of promoter contains four control elements: basic promoter (1): This sequence is a 7 bp conserved region with the center of -25 ~-30, which is called TATA frame or Goldberg-Hogness frame. It is related to the position of RNA polymerase, where DNA double strands are unbound, which determines the starting point of transcription. Without TATA box, transcription will start at many sites. 2 Initiator: a conserved sequence of the transcription starting point, * * * has the sequence: PyPyANT(A)PyPy Py is a pyrimidine base (c or t), n is an arbitrary base, and a is the transcription starting point. Here, DNA is untied and transcription begins. 3 Upstream factors: Common upstream elements include CAAT framework, GC framework and octamer framework. The * * * sequence of CAAT box is GCCAATCT, the * * sequence of GC box is GGGCGG and CCGCCC, the octamer box contains 8bp, and the * * sequence is ATGCAAAT；; 4. Response element: The transcription activating factor produced by induced regulation binds to the response element on the target gene. For example, the * * sequence of heat shock effect element HSE is CNNGAANNTCCNNG, which can be recognized and acted by heat shock factor HSF; The * * * of serum effector SRE has the sequence CCATATTAGG, which can be recognized and acted by serum effector SRF. There are many factors involved in the transcription initiation of RNA polymerase II, which can be divided into three categories: 1 universal factor: the auxiliary factor acting on the basic promoter is called universal transcription factor (GTF Ⅱ H Ⅱ D Ⅱ A ⅹ), or basic transcription factor, which is necessary for any cell type II promoter to start transcription, represented by TF Ⅱ ⅹ, in which ⅹ is expressed. Upstream factor: or transcription cofactor, refers to the transcription factor that recognizes upstream elements. Inducing factors: In eukaryotes, gene expression related to cell types and developmental stages is mainly regulated by transcription factor biosynthesis, which is a long-term process. The rapid response to external stimuli is mainly induced by transcription activating factors. These induced transcription activators bind to the so-called response elements on the target gene. Class III promoters: Class III promoters are recognized by RNA polymerase III, which involves the transcription of some small RNA molecules. The promoter of RNA polymerase III has three types of structures: 1 type 1 type intragenic promoter: for example, the promoter of 5S rRNA gene, which is located downstream of the transcription start point, that is, inside the gene, is a downstream promoter with two frame sequences and is recognized by three cofactors. The promoter of 5S rRNA gene consists of three elements: frame A (box A), intermediate element and frame C (box C). Tf ⅲ a binds to frame a, and then promotes TF ⅲ c binding, leading to TF ⅲ b binding near the transcription start point and guiding RNA polymerase ⅲ to bind to the start point. Tf ⅲ b makes RNA polymerase ⅲ locate correctly and plays the role of "location factor". Type 2 gene promoter: For example, the promoter of tRNA gene has two control elements, namely, frame A and frame B..Tf ⅲ c binds to frame B, and its binding region includes frame A and frame B, which then leads to TF ⅲ b binding near the transcription start point and RNA polymerase ⅲ binding to the start point. Upstream promoter: such as the promoter of snRNA gene, located upstream of the transcription origin. There are three upstream elements: OCT (octamer motif), PSE (proximal sequence element) and TATA element. In the upstream promoter of RNA polymerase ⅲ, transcription can only be started if there is TATA element near the starting point. However, the existence of PSE and OCT elements will increase transcription efficiency.
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What are the promoters of bacteria?
The promoter of bacteria contains several scattered sequences, namely -35 region, extended-10 region,-10 region, σ factor recognition region and UP element recognized by carboxyl terminal domain of α subunit. All bacteria have an essential σ factor called housekeeping σ factor (for example, σ 70 in E.coli; Also known as RpoD), which is responsible for identifying most promoters (Figure 1b). The housekeeping σ factor consists of four domains connected by a flexible linker. In RNA polymerase holoenzyme, σ factor binds to the subunit of ribozyme, so that each domain of σ factor interacts with a specific promoter element. Domains 3 and 4 of σ factor are mainly used to locate RNA polymerase, and domains 1 and 2 are mainly used to promote the formation of open complexes. Another function of housekeeping σ factor is regulated by domain 1, which can ensure that DNA does not enter the active region before RNA binds to the promoter. When RNA polymerase binds to the promoter, it triggers conformational changes and allows DNA to enter the active region. Diseases with functional variation of extended data promoter: It is confirmed from human mendelian genetics (OMIM) that it is related to promoter failure, whether it is due to direct mutation of promoter sequence or mutation of transcription factor or transcription * * * stimulating factor. However, many cancers are not listed because chimeric genes are produced by chromosome translocation: asthma β thalassemia, Rubinstein Taibbi syndrome. It should be noted that most diseases are heterogeneous in etiology. At the molecular level, one disease often refers to multiple diseases, even if its symptoms and treatment methods are consistent. The different responses of diseases to treatment are due to the different molecular sources behind them, which will be the category of pharmacogenetics. Baidu encyclopedia-promoter
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Commonly used regulatory promoters in prokaryotic expression systems
Lactose promoter, tryptophan
Promoter), Tac (hybrid promoter of lactose and tryptophan), lPL (l phage
Left promoter), T7 phage promoter, etc.
(1)Lac promoter: It comes from E.coli.
Lactose operon
It's a DNA molecule
The last targeted nucleotide sequence consists of a repressor gene (LacI), a promoter gene (P), an operator gene (O) and gene structures encoding three enzymes related to lactose utilization. Lac promoter is catabolized.
Positive regulation of system and negative regulation of repressor. Positive regulation activates the promoter through CAP (catabolite gene activation protein) factor and cAMP, which promotes transcription. Negative regulation refers to the regulation of genes to produce LacZ repressor protein, which can combine with the manipulation genes to prevent transcription. Lactose and some analogues, such as IPTG, can form a complex with repressor protein, change its configuration, and cannot combine with O gene, thus relieving this repression and inducing transcription.
(2)trp promoter: trp operon from E.coli, whose repressor protein must be bound to tryptophan to be active. When tryptophan is deficient, the promoter begins to transcribe. When tryptophan is abundant, transcription stops. B- indole
acrylic acid
It can competitively inhibit the combination of tryptophan and repressor protein, inactivate repressor protein and promote the transcription of trp promoter.
(3)Tac promoter: Tac promoter is a group of hybrid promoters artificially constructed by Lac and trp promoters, which is negatively regulated by Lac repressor protein and has stronger startup ability than Lac and trp. Among them, Tac 1 consists of -35 region of Trp promoter plus a synthetic 46 bp DNA fragment (including Pribnow box) and Lac operon gene, and Tac 12 consists of -35 region of Trp promoter and-10 region of Lac promoter, plus Lac operon and the operon gene in SD sequence. Tac promoter was induced by IPTG.
(4)lPL promoter: Derived from the early left transcription promoter of L phage, it is a strong promoter with activity about 1 1 times higher than Trp promoter. LPL promoter is controlled by temperature-sensitive repressor cIts857. At low temperature (30℃), cIts857 repressor protein can inhibit the transcription of PL promoter. At high temperature (45℃), cIts857 protein was inactivated, repression was released, and PL promoter was transcribed. Because of cIts857, the system is especially suitable for expressing gene products that are toxic to Escherichia coli. The disadvantage is that temperature conversion can induce not only PL promoter, but also heat shock genes, some of which encode protease.
. This contradiction can be alleviated if L phage cI+ lysogenic bacteria are used and induced by mitomycin C or nalidixic acid.
(5)T7 phage promoter: It is a promoter from T7 phage with high specificity.
Only T7RNA polymerase.
Can be started, so the cloned gene can be expressed independently. The efficiency of T7RNA polymerase is about 5 times higher than that of Escherichia coli RNA polymerase. It can make the plasmid transcribe continuously along the template for several weeks, and there are many exogenous terminators.
It can not effectively terminate its sequence, so it can transcribe some sequences that Escherichia coli RNA polymerase can not effectively transcribe. This system can efficiently express genes that cannot be effectively expressed by other systems. However, it should be noted that when using this promoter, the host must contain T7RNA polymerase. The application of T7 phage expression system requires two conditions: one is to have T7 phage RNA polymerase, which can be produced by infected L phage or by gene copy inserted into Escherichia coli chromosome; The second is a vector with T7 phage promoter upstream of the gene to be expressed.
Answer on 2011-12-09.
Agree 5
Professional mrna drug research and development technology development, providing CRO related technical services, mrna drug research and development -LNP.
Yi Miaoda has an independent platform for mrna drug research and development-LNP, which provides professional services for mrna drug research and development based on biomedicine and other fields-LNP technology development, cationic lipid technology development and authorization. Welcome to cooperate in the development of mrna drug research and development -LNP products.
Shanghai yimiaoda biotechnology advertisement
Tianshui-how much is the pregnancy paternity test-affordable!
Someone asked 26 minutes ago.
How much does it cost to do paternity test during pregnancy? -Unintended pregnancy, I don't know who the fetus is, and the paternity test during pregnancy is accurate! Safety and security, reasonable fees for the benefit of the people, click for details.
Xiamen Ankang Shanghai biology science and technology co., ltd. ... advertisement
It's only three months since the self-reported diagnosis of anti-tumor chemotherapy, and the targeted gene is simply solved.
Anti-tumor chemotherapy, targeted gene, only three months after diagnosis, I didn't expect to live the same life as healthy people. I hope to help more patients ... target genes ... details. ...
advertisement
What is the upstream promoter element of eukaryotes?
There are three types of eukaryotic promoters, which are transcribed by RNA polymerase ⅰ, ⅱ and ⅲ respectively. ⅰ (type ⅰ promoter: only controls the transcription of rRNA precursor gene, and the transcript is cut and processed to generate various mature rRNA. Class I promoter consists of two conserved sequences: the core promoter, located near the transcription start point, from -45 to+20; Upstream control element (UCE): located between-180 and-107; RNA polymerase I needs two factors to participate in its transcription: the polypeptide chain with ubf 1:m of 97000 binds to the GC-rich regions of the above two parts; 1 TBP, namely TATA binding protein (TBP); SL 1: A tetrameric protein containing three different transcription cofactors TAFⅰ Ⅰ: Under the mediation of SL 1, RNA polymerase I binds to the transcription origin and starts transcription. Class Ⅱ promoters: Class Ⅱ promoters are involved in controlling the expression of many genes encoding protein. This kind of promoter contains four control elements: basic promoter (1): This sequence is a 7 bp conserved region with the center of -25 ~-30, which is called TATA frame or Goldberg-Hogness frame. It is related to the position of RNA polymerase, where DNA double strands are unbound, which determines the starting point of transcription. Without TATA box, transcription will start at many sites. 2 Initiator: a conserved sequence of the transcription starting point, * * * has the sequence: PyPyANT(A)PyPy Py is a pyrimidine base (c or t), n is an arbitrary base, and a is the transcription starting point. Here, DNA is untied and transcription begins. 3 Upstream factors: Common upstream elements include CAAT framework, GC framework and octamer framework. The * * * sequence of CAAT box is GCCAATCT, the * * sequence of GC box is GGGCGG and CCGCCC, the octamer box contains 8bp, and the * * sequence is ATGCAAAT；; 4. Response element: The transcription activating factor produced by induced regulation binds to the response element on the target gene. For example, the * * sequence of heat shock effect element HSE is CNNGAANNTCCNNG, which can be recognized and acted by heat shock factor HSF; The * * * of serum effector SRE has the sequence CCATATTAGG, which can be recognized and acted by serum effector SRF. There are many factors involved in the transcription initiation of RNA polymerase II, which can be divided into three categories: 1 universal factor: the auxiliary factor acting on the basic promoter is called universal transcription factor (GTF Ⅱ H Ⅱ D Ⅱ A ⅹ), or basic transcription factor, which is necessary for any cell type II promoter to start transcription, represented by TF Ⅱ ⅹ, in which ⅹ is expressed. Upstream factor: or transcription cofactor, refers to the transcription factor that recognizes upstream elements. Inducing factors: In eukaryotes, gene expression related to cell types and developmental stages is mainly regulated by transcription factor biosynthesis, which is a long-term process. The rapid response to external stimuli is mainly induced by transcription activating factors. These induced transcription activators bind to the so-called response elements on the target gene. Class ⅲ promoter: Class ⅲ promoter is recognized by RNA polymerase III, which involves the transcription of some small RNA molecules. The promoter of RNA polymerase III has three types of structures: 1 type 1 type intragenic promoter: for example, the promoter of 5S rRNA gene, which is located downstream of the transcription start point, that is, inside the gene, is a downstream promoter with two frame sequences and is recognized by three cofactors. The promoter of 5S rRNA gene consists of three elements: frame A (box A), intermediate element and frame C (box C). Tf ⅲ a binds to frame a, and then promotes TF ⅲ c binding, leading to TF ⅲ b binding near the transcription start point and guiding RNA polymerase ⅲ to bind to the start point. Tf ⅲ b makes RNA polymerase ⅲ locate correctly and plays the role of "location factor". Type 2 gene promoter: For example, the promoter of tRNA gene has two control elements, namely, frame A and frame B..Tf ⅲ c binds to frame B, and its binding region includes frame A and frame B, which then leads to TF ⅲ b binding near the transcription start point and RNA polymerase ⅲ binding to the start point. Upstream promoter: such as the promoter of snRNA gene, located upstream of the transcription origin. There are three upstream elements: OCT (octamer motif), PSE (proximal sequence element) and TATA element. In the upstream promoter of RNA polymerase ⅲ, transcription can only be started if there is TATA element near the starting point. However, the existence of PSE and OCT elements will increase transcription efficiency.
Chiba Electric Appliances 168
40 like 9 149 browsing
More experts
What are the promoters?
Expert 1 online Q&A to 1.
Reply within 5 minutes |10,000 professional interviewees
Ask questions at once
The most beautiful fireworks consulted a health care question and made a favorable comment.
Lan Qiuwangzi consulted a health care problem and made a good comment.
Garlic asked a health care question and made a favorable comment.
188 * * * 8493 consulted a health care problem and made a favorable comment.
Basketball big picture consulted a health care problem and made a good comment.
The animal park consulted a health care problem and gave a favorable comment.
AKA asked a health care question and made a favorable comment.
What are the promoters of bacteria?
The promoter of bacteria contains several scattered sequences, namely -35 region, extended-10 region,-10 region, σ factor recognition region and UP element recognized by carboxyl terminal domain of α subunit. All bacteria have an essential σ factor called housekeeping σ factor (for example, σ 70 in E.coli; Also known as RpoD), which is responsible for identifying most promoters (Figure 1b). The housekeeping σ factor consists of four domains connected by a flexible linker. In RNA polymerase, σ factor binds to the subunit of ribozyme so that each domain of σ factor interacts with a specific promoter element. Domains 3 and 4 of σ factor are mainly used to locate RNA polymerase, and domains 1 and 2 are mainly used to promote the formation of open complexes. Another function of housekeeping σ factor is regulated by domain 1, which can ensure that DNA does not enter the active region before RNA binds to the promoter. When RNA polymerase binds to the promoter, it triggers conformational changes and allows DNA to enter the active region. Diseases with functional variation of extended data promoter: It is confirmed from human mendelian genetics (OMIM) that it is related to promoter failure, whether it is due to direct mutation of promoter sequence or mutation of transcription factor or transcription * * * stimulating factor. However, many cancers are not listed because chimeric genes are produced by chromosome translocation: asthma β thalassemia, Rubinstein Taibbi syndrome. It should be noted that most diseases are heterogeneous in etiology. At the molecular level, one disease often refers to multiple diseases, even if its symptoms and treatment methods are consistent. The different responses of diseases to treatment are due to the different molecular sources behind them, which will be the category of pharmacogenetics. Baidu encyclopedia-promoter
Vivi Miao 0597
1 like 8087 browsing
How much does it cost to be a pregnant dna paternity? -Price list!
Ankang (Shanghai) Biotechnology Advertisement
It's only three months since the self-reported diagnosis of anti-tumor chemotherapy, and the targeted gene is simply solved.
Targeted gene recommendation information worth seeing.
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