What are the three bases in a promoter?

Regulable promoters commonly used in prokaryotic expression systems include Lac (lactose promoter), Trp (tryptophan promoter), Tac (hybrid promoter of lactose and tryptophan), lPL (leftward promoter of l phage), T7 phage promoter, etc.

(1) Lac promoter: It comes from the lactose operon of Escherichia coli. It is a directional nucleotide sequence on the DNA molecule. It consists of a repressor protein gene (LacI), a promoter gene (P), It consists of an operator gene (O) and a gene structure encoding three enzymes related to lactose utilization. The Lac promoter is positively regulated by the catabolic system and negatively regulated by the repressor. Positive regulation activates the promoter through CAP (catabolite gene activation protein) factors and cAMP to promote transcription. Negative regulation is the production of LacZ repressor protein by the regulatory gene, which can bind to the operator gene to prevent transcription. Lactose and certain analogs such as IPTG can form a complex with the repressor protein, changing its configuration and being unable to bind to the O gene, thus releasing this repression and inducing transcription.

(2) trp promoter: It comes from the tryptophan operon of E. coli, and its repressor protein must bind to tryptophan to be active. This promoter initiates transcription when tryptophan is lacking. When tryptophan is abundant, transcription ceases. b-indole acrylic acid can competitively inhibit the binding of tryptophan to the repressor protein, relieve the activity of the repressor protein, and promote the transcription of the trp promoter.

(3) Tac promoter: Tac promoter is a group of hybrid promoters artificially constructed from Lac and trp promoters. It is negatively regulated by Lac repressor protein and has a higher startup capacity than Lac and trp promoters. All strong. Tac 1 is composed of the -35 region of the Trp promoter plus a synthetic 46 bp DNA fragment (including the Pribnow box) and the Lac operator gene. Tac 12 is composed of the -35 region of the Trp promoter and -10 of the Lac promoter. region, plus the operator part of the Lac operon and the SD sequence. The Tac promoter is induced by IPTG.

(4) lPL promoter: It comes from the early left-directed transcription promoter of l phage and is a strong promoter about 11 times more active than the Trp promoter. The lPL promoter is controlled by the temperature-sensitive repressor cIts857. At low temperature (30°C), the cIts857 repressor protein can inhibit the transcription of the PL promoter. At high temperature (45°C), the cIts857 protein is inactivated, repression is released, and transcription of the PL promoter is promoted. Because the system is affected by cIts857, it is particularly suitable for expressing gene products that are toxic to E. coli. The disadvantage is that temperature conversion can not only induce the PL promoter, but also induce heat shock genes, some of which encode proteases. This contradiction can be alleviated if phage cI+ lysogens are used and induced with mitomycin C or nalidixic acid.

(5) T7 phage promoter: It is a promoter from T7 phage and has high specificity. Only T7 RNA polymerase can start it, so the cloned gene can be expressed alone. The efficiency of T7 RNA polymerase is about 5 times higher than that of E. coli RNA polymerase. It can enable the plasmid to be continuously transcribed along the template for several weeks. Many exogenous terminators cannot effectively terminate its sequence, so it can transcribe some sequences that cannot be transcribed by the large intestine. Sequences efficiently transcribed by Bacillus RNA polymerase. This system can efficiently express genes that other systems cannot. But please note that when using this promoter, the host must contain T7 RNA polymerase. The application of the T7 phage expression system requires two conditions: the first is to have T7 phage RNA polymerase, which can be produced by the infected phage or by a copy of the gene inserted into the E. coli chromosome; the second is to have the upstream band of a gene to be expressed Vector with T7 phage promoter.

Answered on 2011-12-09

Agree with 5

Professional mrna drug research and development technology development, providing CRO related technical services, mrna drug research and development-LNP

Yimiaoda has an independent research and development platform for mrna drug research and development - LNP. Based on biomedicine and other fields, it provides professional mrna drug research and development - LNP technology development services, as well as cationic lipid technology development, licensing and other services. Welcome to cooperate in the development of mRNA drug research and development-LNP products.

Shanghai Yimiaoda Biotechnology Advertisement

Tianshui - How much does it cost to do a paternity test during pregnancy - the price is affordable!

Some people asked related questions 26 minutes ago

How much does it cost to do a paternity test during pregnancy? - Unexpected pregnancy and you don’t know who the fetus is, accurate paternity test during pregnancy! It’s safe and secure, the fees are reasonable and benefit the people, click to inquire for details.

Ankang Shanghai Biotechnology Co., Ltd. Xiamen... Advertisement

Reporting that anti-tumor chemotherapy has been diagnosed with only three months left, and the targeted gene is a simple solution

Anti-tumor Chemotherapy, targeted genes, and I only had three months left after my diagnosis. Unexpectedly, I could still live a life like a healthy person. I hope it can help more patients...target genes...details...

What are the upstream promoter elements of eukaryotes

There are three types of eukaryotic promoters, which are transcribed by RNA polymerases I, II and III respectively. Class I promoter: only controls the transcription of rRNA precursor genes, and the transcripts are cleaved and processed to generate various mature rRNAs. Category I promoters are composed of two parts of conserved sequences: core promoter: located near the transcription start point, from -45 to +20; upstream control element (UCE): located from -180 to -107; RNA Polymerase I requires the participation of two factors for its transcription: UBF1: a polypeptide chain with an M of 97,000, combined in the GC-rich region of the above two parts; 1 TBP, which is TATA-binding protein (TBP); SL1: a tetrameric protein containing three different transcription cofactors TAFⅠ; under the mediation of SL1 factor, RNA polymerase I binds to the transcription start point and starts transcription. Class II promoters: Class II promoters are involved in the control of expression of numerous protein-coding genes. This type of promoter contains 4 types of control elements: 1. Basal promoter: The sequence is a 7 bp conserved region centered around -25 to -30, TATAAAA/T, called the TATA box or Goldberg-Hogness box. Relevant to the positioning of RNA polymerase, where the DNA double strands are unwound and determine the starting point of transcription. Without the TATA box, transcription will start at many sites. 2 Initiator: a conserved sequence at the starting point of transcription. The most common sequence is: PyPyANT(A)PyPy. Py is a pyrimidine base (C or T), N is any base, and A is the starting point of transcription. . Here the DNA unwraps and transcription begins. 3 Upstream elements (upstream factor): Common upstream elements include CAAT box, GC box and octamer box, etc. The only sequence of the CAAT box is GCCAATCT, the last sequence of the GC box is GGGCGG and CCGCCC, the octamer box contains 8 bp, and the last sequence is ATGCAAAT; 4 response element (response element): induced regulation production The transcriptional activator binds to the response element on the target gene. For example, the *** sequence of the heat shock response element HSE is CNNGAANNTCCNNG, which can be recognized and acted upon by the heat shock factor HSF; the *** sequence of the serum effector element SRE is CCATATTAGG, which can be recognized and acted upon by the serum effector SRF.

There are a large number of various factors involved in the initiation of RNA polymerase II transcription, which can be divided into three categories: 1. General factor: The cofactor that acts on the basic promoter is called a general (transcription) factor (GTF). Or basic transcription factor (basal transcription), which is necessary for the initiation of transcription by any cell type II promoter, represented by TFIIX, where X is named with English letters in the order of discovery, such as TFIIA, TFIIID, and TFIIH. 2 Upstream factor: or transcription ancillary factor, refers to a transcription factor that recognizes upstream elements. 3. Inducible factors: In eukaryotes, gene expression related to cell types and developmental stages is mainly regulated through the de novo synthesis of transcription factors, which is a long-term process. The rapid response to external stimuli is mainly regulated by the inducibility of transcription activators. These induced transcriptional activators bind to so-called response elements on target genes. Class III promoter: Class III promoter is recognized by RNA polymerase III and is involved in the transcription of some small RNA molecules. The promoter of RNA polymerase III has three types of structures: Type 1 Intragenic promoter: For example, the promoter of the 5S rRNA gene is located downstream of the transcription start point, that is, inside the gene. It is a downstream promoter and has two framework sequences. Recognized by 3 cofactors. The promoter of the 5S rRNA gene consists of three elements: box A, intermediate element and box C. TFIIIA binds to frame A, which then prompts TFIIIC to bind. The latter binding causes TFIIIB to bind near the transcription start point and guide RNA polymerase III to bind to the start point. TFIIIB enables the correct positioning of RNA polymerase III and functions as a "positioning factor". Type 2 intragenic promoter: such as the promoter of a tRNA gene, which has two control elements, namely frame A and frame B. TFIIIC binds to frame B, and its binding region includes frame A and frame B, which then causes TFIIIB to bind near the transcription start point and guide RNA polymerase III to bind to the start point. 3 Upstream promoter: such as the promoter of snRNA gene, located upstream of the transcription start point. 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 be initiated only if the TATA element is present near the origin. However, the presence of PSE and OCT elements will increase transcription efficiency.

Qianye Electric 168

40 likes 9149 views

More experts

What are the promoters

Experts answer questions online one-on-one

Response within 5 minutes | Tens of thousands of professional answerers

Ask a question immediately

The most beautiful fireworks ask a health question and publish it Received a positive review

lanqiuwangzi asked about a health issue and posted a positive review

garlic asked about a health issue and posted a positive review

188****8493 Consultation A question about health care was asked and a positive comment was made

Basketball Big Picture asked a question about health preservation and a positive comment was made

Animal Paradise asked a question about health preservation and a positive comment was made

AKA asked about a health issue and gave a favorable comment

What are the bacterial promoters

In the RNA polymerase holoenzyme, sigma factors bind to subunits of the core enzyme such that each domain of the sigma factor interacts with specific promoter elements. The main role of domains 3 and 4 of sigma factor is the initial positioning of RNA polymerase, and the main role of domains 1 and 2 is to promote the formation of open complexes. Another function of the housekeeping sigma factor is regulated by domain 1, which ensures that DNA does not enter the active region before RNA binds to the promoter. When RNA polymerase binds to the promoter, it triggers a conformational change to allow DNA to enter the active region. Extended information Diseases with promoter functional variation: The following are confirmed from Mendelian Inheritance in Man (OMIM) to be related to promoter failure, whether due to direct mutations in the promoter sequence or mutations in transcription factors or transcription factor stimulating factors. Various cancers not listed are due to mosaic genes arising from chromosomal translocations: asthma, beta-thalassemia, Rubinstein Taibbi syndrome. It should be noted that most diseases are heterogeneous in etiology, and at the molecular level a disease often refers to multiple diseases, even if their symptoms and treatments are the same. Diseases have different responses to treatments due to differences in the underlying molecular sources. This would be the category of pharmacogenetics. Baidu Encyclopedia - Promoter

Meow Meow Meow 0597

1 likes 8087 views

How much does it cost to do a DNA paternity test during pregnancy - price list!

Ankang (Shanghai) Biotechnology Advertisement

Reporting that anti-tumor chemotherapy has been used to diagnose and only have three months left to solve it simply by targeting genes

Relevant targeted genes worth watching Information recommendation

Chengdu Huakai Fugui Technology Advertisement

Regulable promoters commonly used in all-prokaryotic expression systems include Lac (lactose promoter), Trp (tryptophan promoter) ), Tac (hybrid promoter of lactose and tryptophan), lPL (left-facing promoter of l phage), T7 phage promoter, etc.

Because the system is affected by cIts857, it is particularly suitable for expressing gene products that are toxic to E. coli. The disadvantage is that temperature conversion can not only induce the PL promoter, but also induce heat shock genes, some of which encode proteases. This contradiction can be alleviated if phage cI+ lysogens are used and induced with mitomycin C or nalidixic acid.

(5) T7 phage promoter: It is a promoter from T7 phage and has high specificity. Only T7 RNA polymerase can start it, so the cloned gene can be expressed alone. The efficiency of T7 RNA polymerase is about 5 times higher than that of E. coli RNA polymerase. It can enable the plasmid to be continuously transcribed along the template for several weeks. Many exogenous terminators cannot effectively terminate its sequence, so it can transcribe some sequences that cannot be transcribed by the large intestine. Sequences efficiently transcribed by Bacillus RNA polymerase. This system can efficiently express genes that other systems cannot. But please note that when using this promoter, the host must contain T7 RNA polymerase. The application of the T7 phage expression system requires two conditions: the first is to have T7 phage RNA polymerase, which can be produced by the infected phage or by a gene copy inserted into the E. coli chromosome; the second is to have a band upstream of a gene to be expressed Vector with T7 phage promoter.

Answered on 2011-12-09

Agree with 5

Professional mrna drug research and development technology development, providing CRO related technical services, mrna drug research and development-LNP

Shanghai Yimiaoda Biotechnology Advertisement

Tianshui - How much does it cost to do a paternity test during pregnancy - the price is affordable!

Some people asked related questions 26 minutes ago

Ankang Shanghai Biotechnology Co., Ltd. Xiamen... Advertisement

Reporting that anti-tumor chemotherapy has been diagnosed with only three months left, and the targeted gene is a simple solution

What are the upstream promoter elements of eukaryotes

2 Initiator: a conserved sequence at the starting point of transcription. The most common sequence is: PyPyANT(A)PyPy. Py is a pyrimidine base (C or T), N is any base, and A is the starting point of transcription. . Here the DNA unwraps and transcription begins. 3 Upstream elements (upstream factor): Common upstream elements include CAAT box, GC box and octamer box, etc. The only sequence of the CAAT box is GCCAATCT, the last sequence of the GC box is GGGCGG and CCGCCC, the octamer box contains 8 bp, and the last sequence is ATGCAAAT; 4 response element (response element): induced regulation production The transcriptional activator binds to the response element on the target gene. For example, the *** sequence of the heat shock effector element HSE is CNNGAANNTCCNNG, which can be recognized and acted upon by the heat shock factor HSF; the *** sequence of the serum effector element SRE is CCATATTAGG, which can be recognized and acted upon by the serum effector factor SRF. There are a large number of various factors involved in the initiation of RNA polymerase II transcription, which can be divided into three categories: 1. General factor: The cofactor that acts on the basic promoter is called a general (transcription) factor (GTF). Or basic transcription factor (basal transcription), which is necessary for the initiation of transcription from any cell type II promoter, represented by TFIIX, where X is named with English letters in the order of discovery, such as TFIIA, TFIIID, and TFIIH. 2 Upstream factor: or transcription ancillary factor, refers to a transcription factor that recognizes upstream elements. 3. Inducible factors: In eukaryotes, gene expression related to cell types and developmental stages is mainly regulated through the de novo synthesis of transcription factors, which is a long-term process. The rapid response to external stimuli is mainly regulated by the inducibility of transcription activator. These induced transcriptional activators bind to so-called response elements on target genes. Class III promoter: Class III promoter is recognized by RNA polymerase III and is involved in the transcription of some small RNA molecules. The promoter of RNA polymerase III has three types of structures: Type 1 Intragenic promoter: For example, the promoter of the 5S rRNA gene is located downstream of the transcription start point, that is, inside the gene. It is a downstream promoter and has two framework sequences. Recognized by 3 cofactors. The promoter of the 5S rRNA gene consists of three elements: box A, intermediate element and box C. TFIIIA binds to frame A, which then prompts TFIIIC to bind. The latter binding causes TFIIIB to bind near the transcription start point and guide RNA polymerase III to bind to the start point. TFIIIB enables the correct positioning of RNA polymerase III and functions as a "positioning factor". Type 2 intragenic promoter: such as the promoter of a tRNA gene, which has two control elements, namely frame A and frame B. TFIIIC binds to frame B, and its binding region includes frame A and frame B, which then causes TFIIIB to bind near the transcription start point and guide RNA polymerase III to bind to the start point. 3 Upstream promoter: such as the promoter of snRNA gene, located upstream of the transcription start point. 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 be initiated only if the TATA element is present near the origin. However, the presence of PSE and OCT elements will increase transcription efficiency.

Qianye Electric 168

40 likes 9149 views

More experts

What are the promoters

Experts answer questions online one-on-one

Response within 5 minutes | Tens of thousands of professional answerers

Ask a question immediately

The most beautiful fireworks ask a health question and publish it

lanqiuwangzi asked about a health issue and gave a favorable comment

garlic asked about a health issue and left a favorable comment

188****8493 Consultation A health question was asked and a positive comment was made

Basketball Big Picture asked a health question and a positive comment was made

Animal Paradise was asked a health question and a positive comment was made

AKA asked about a health issue and gave a favorable comment

What are the bacterial promoters

The bacterial promoter contains several scattered sequences, -35 region, extended- Region 10, -10 region, the recognition region of sigma factor and the UP element recognized by the carboxyl-terminal domain of the alpha subunit. All bacteria possess an essential sigma factor, called a housekeeping sigma factor (e.g., σ70 in E. coli; also known as RpoD), which is responsible for recognition of most promoters (Fig. 1b). The housekeeping sigma factor consists of 4 domains connected by flexible linkers. In the RNA polymerase holoenzyme, sigma factors bind to subunits of the core enzyme such that each domain of the sigma factor interacts with specific promoter elements. The main role of domains 3 and 4 of sigma factor is the initial positioning of RNA polymerase, and the main role of domains 1 and 2 is to promote the formation of open complexes. Another function of the housekeeping sigma factor is regulated by domain 1, which ensures that DNA does not enter the active region before RNA binds to the promoter. When RNA polymerase binds to the promoter, it triggers a conformational change to allow DNA to enter the active region. Extended information Diseases with promoter functional variation: The following are confirmed from Mendelian Inheritance in Man (OMIM) to be related to promoter failure, whether due to direct mutations in the promoter sequence or mutations in transcription factors or transcription factor stimulating factors. Various cancers not listed are due to mosaic genes arising from chromosomal translocations: asthma, beta-thalassemia, Rubinstein Taibbi syndrome. It should be noted that most diseases are heterogeneous in etiology, and at the molecular level a disease often refers to multiple diseases, even if their symptoms and treatments are the same. Diseases have different responses to treatments due to differences in the underlying molecular sources. This would be the category of pharmacogenetics. Baidu Encyclopedia - Promoter

Meow Meow Meow 0597

1 likes 8087 views

How much does it cost to do a DNA paternity test during pregnancy - price list!

Ankang (Shanghai) Biotechnology Advertisement

Reporting that anti-tumor chemotherapy has been used to diagnose and only have three months left to solve it simply by targeting genes

Relevant targeted genes worth watching Information recommendation

Chengdu Huakai Fugui Technology Advertising