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Expression vectors, also known as expression constructs, are usually plasmids or viruses designed for gene expression in cells. Vectors are used to introduce a particular gene into a target cell and can direct the cellular mechanism for protein synthesis to produce the protein encoded by the gene. Expression vectors are the basic tool of biotechnology for protein production.
The vector is engineered to include regulatory sequences that act as enhancer and promoter areas and result in green transcription of the gene carried at the expression vector. The purpose of a well-designed expression vector is the green manufacturing of protein, and this could be performed with the aid of using the manufacturing of a great quantity of strong messenger RNA that may then be translated into protein. Protein expression can be tightly controlled, producing large amounts of protein only when needed using an inducer, but some systems allow the protein to be expressed constitutively.
The expression vector is characterized in that each vector can have an appropriate position for inserting the gene as a marker selectable and a plurality of cloning sites that can be selected. The cloned gene can be transferred to the expression vector from a special cloning vector but can be cloned directly into the expression vector. The cloning process is usually performed in E.coli. The vector used for protein production in other organisms such as E. coli is called the element that allows them, and these vectors are called shuttle vectors.
Expression vectors are transformed or transfected into host cells for protein synthesis. Some expression vectors may have elements for transformation or insertion of DNA into the host chromosome, such as the vir gene for plant transformation and the integrase site for chromosomal integration.
Difference between Expression Vector and Cloning Vector
Cloning vectors and expression vectors are two types of vectors used in recombinant DNA techniques to carry foreign DNA segments to target cells. Both clone vectors and expression vectors include replication starting points, unique restriction sites and selectable marker genes in their vector sequences. Cloning vectors can be plasmids, cosmids, or bacteriophages. The main difference between a cloning vector and an expression vector is that the cloning vector is used to transport foreign DNA segments to host cells, whereas the expression vector is a type of cloning that contains an appropriate expression signal with maximum gene expression.
Cloning Vector | Expression Vector |
|---|---|
It is a small piece of DNA that is stably maintained within a host cell. It is used to introduce genes into the cells while obtaining numerous copies of the insert | It is a plasmid that is used to introduce a specific gene into the target cell and commander cell’s mechanisms which produces the relevant gene product |
used for obtaining numerous copies of the DNA segment | Used for obtaining gene product of the inserted DNA segment, either RNA or protein |
They can be cosmids, plasmids, phages, BACs, YACs or MACs | It is a plasmid vector |
It comprises an origin of replication, a selectable marker and unique restriction sites | It comprises enhancers, the promoter region, transcription initiation sequence, termination codon and translation initiation sequence, in addition to the typical features of a cloning vector |
More about Cloning Vectors
function as carrier DNA molecules. All cloning vectors have four characteristics:
They self-replicate with the foreign DNA segments they carry
They contain multiple restriction sites that are unique to the vector
They have selectable markers, usually in the form of antibiotic resistance genes that are not present in the host genome
They can be extracted relatively easily from the host cell
Examples of Expression Vectors
Many vegetable expression vectors are based on the Ti plasmid of Agrobacterium-clamps. In these expression vectors, the DNA inserted into the plant can be cloned into T DNA, and the adjacent DNA can be incorporated into the plant genome through a 25 Benz direct repetitive sequence at both ends. T DNA also contains selection markers.
Mammalian expression vectors provide greater advantages in mammalian protein expression than bacterial expression systems, proper folding, post-translational modifications, and associated enzymatic activity. It may also be preferable to other non-mammalian eukaryotic systems where the expressed protein may not contain the correct glycosylation. It requires chaperones for proper folding and stability and is particularly useful for the production of membrane-bound proteins with numerous post-translational modifications.
Conclusion
An expression vector was used to introduce the vitamin A precursor beta-carotene into the rice. This product is called Golden Rice. This process is also used to introduce into plants a gene that produces an insecticide called Bacillus thuringiensis toxin or Bt toxin.
This reduces the need for farmers to apply pesticides as they are produced by the modified organism. In addition, expression vectors are used to prolong tomato maturation by modifying plants to reduce the production of chemicals that spoil tomatoes. Due to unknown health risks, the company’s ability to patent certain genetically modified food crops, and the fact that there may be ethical concerns, there is controversy over using expression vectors to modify crops. Was. Nevertheless, this technique is still in use and has been extensively studied.
