Due to their important functions, proteins are widely used for nutritional, medical and industrial applications. In this lesson, we will learn about how large amounts of a specific protein is generated.
By the end of this lesson, you'll know about
Recombinant DNA technology is an important way to generate large amounts of a specific protein. It involves the use of genetic recombination to bring together genetic material from multiple sources and creating DNA sequences that are naturally not found in the genome. Proteins produced with the recombinant DNA technology are the Recombinant Proteins.
Recombinant DNA (rDNA) is a DNA strand that is formed by the combination of two or more DNA sequences. Genetic recombination is a naturally occurring process, but when it is artificially manipulated it is called recombinant DNA technology. Using rDNA technology, scientists are able to create new DNA sequences that would not naturally exist under normal circumstances and environmental conditions.
The resulting recombinant DNA consists of a plasmid in which the genes of a target protein is cloned. When the plasmid is introduced to a host expression system, the host’s own protein synthesis pathways will then result in the expression of the protein of choice – the so-called recombinant protein. This provides large quantities of a given protein for research, diagnostic, or even therapeutic uses.
Simply isolating proteins from their natural sources cannot meet the growing demand for proteins. The recombinant DNA technology provides a more efficient method to obtain large amounts of proteins.
There is a range of recombinant protein types that can be used in drug development or research. Some of these are – chemokines, interferons, colony stimulating factors, and growth factors.
Recombinant proteins are used to develop some current therapeutics, for example, human insulin. Recently approved recombinant protein drugs are used to treat a wide variety of conditions including cancer, autoimmune diseases, and genetic disorders.
Considerable advances in technology have enabled the expression and isolation of recombinant proteins on a large scale. The amount of protein required for large scale applications such as enzyme, antibody or vaccine production is considerably high. This requires that the system in which the protein is expressed must be easy to culture and maintain, grow rapidly, and produce large amounts of protein. These requirements led to the discovery of protein expression systems.
The various types of protein expression systems are bacteria, yeast, insect or mammalian systems.
The recombinant DNA technology involves the transfer of a foreign DNA into a self-replicating genetic element of an organism, which eventually leads to the amplification of the foreign DNA.
Currently, there are three major methods to make recombinant DNA:
1. Transformation – A foreign DNA fragment is cut and inserted into a vector, usually a plasmid. Next, the resulting vector is put into a host cell, such as the bacterium E.coli, where the foreign DNA fragment is expressed. The process of bacterial cell taking up foreign DNA is called transformation.
2. Non-bacterial transformation – It does not use bacteria as a host cell. One example is DNA microinjection, where a foreign DNA is injected directly into the nucleus of the recipient cell. Biolistics is a method in which high-velocity microprojectiles are used to help bombard foreign DNA into the recipient cell.
3. Phage introduction – In phage introduction, a phage is used to transfer foreign DNA into the host cell, and eventually the phage DNA containing foreign DNA is inserted into the host cell’s genome.
Recombinant DNA technology allows the manipulation of the properties of the protein of interest. In these aspects, recombinant DNA technology and recombinant proteins are beneficial. However, there are some concerns about the safety and ethics of the use of recombinant DNA technology.
