Recombinant DNA Technology: An Overview

What is Recombinant DNA Technology?

Recombinant DNA technology is the manipulation and isolation of specific DNA segments from various species and the subsequent linking of the segments to the DNA of a virus or bacterial plasmid. These molecules are then introduced into a host cell where they can replicate. Plasmids, artificial chromosomes, and bacteriophages serve as vectors, facilitating the replication of recombinant DNA sequences within host organisms.

“Recombinant DNA” comes from the term “recombination” which means the rearrangement of genetic material, especially by crossing over in chromosomes or by the artificial joining of segments of DNA from different organisms. In other words, recombinant DNA technology is genetic engineering and gene editing.

The development of this technology was a significant milestone in the history of science. From its inception, gene editing was a promising advancement in the development of therapies and medicine. Recombinant DNA technology would lead to life-saving treatments for many different diseases and disorders, including diabetes and cancer.

History of Recombinant DNA

Research into recombinant DNA technology grew in popularity during the 1960’s and 1970’s and led to discoveries that would change the course of science and medicine. During the 60’s, scientists were speculating that DNA recombination could happen within cells but did not understand the mechanisms behind it. In 1967, Martin Gellert and researchers at the National Institute of Health made a world-changing discovery. The team found an enzyme, DNA ligase, that forms phosphodiester bonds between DNA ends, allowing it to join different DNA segments. This discovery was one of the first steps that would lead to recombinant DNA technology and gene editing. Around the same time, researcher Werner Arber and colleagues discovered restriction enzymes which cleave DNA at specific nucleotide sequences. The characterization of restriction enzymes gave scientists the ability to cut specific pieces of DNA to obtain the desired recombination.

Additional breakthroughs in recombinant DNA technology occurred in the early 1970’s. In 1972 Paul Berg developed an experiment to transfer foreign DNA into mammalian cells. Utilizing the SV40 tumor virus as a vector, the researchers integrated segments of λ phage DNA, as well as a segment of E. coli DNA containing the galactose operon, into the SV40 genome. This experiment demonstrated that recombinant technologies could be applied to any DNA sequence regardless of how different the species were. Even though the researchers did not introduce foreign DNA into a mammalian cell in the experiment, they proved that it could be done. In 1973, Stanley Cohen and colleague Annie Chang described the first plasmid vector. The researchers took two genes for antibiotic resistance from two separate plasmids, joined them, and introduced them into E.coli. A portion of the transformed bacteria demonstrated resistance to both antibiotics, showing for the first time that bacterial plasmids created in vitro were functional in bacteria.

Once recombinant DNA technology was shown to be possible, its applications quickly grew in the therapeutics, food, and agriculture industries.

Recombinant DNA Steps

Recombinant DNA is made up of sequences that can come from a variety of sources. The process to create recombinant DNA involves:

  1. Isolating the genetic material
  2. Cutting the DNA at specific locations with restriction enzymes
  3. Joining the DNA fragments with DNA ligase
  4. Inserting the DNA into the host cell
  5. Selecting and screening for the transformed cells

 

This process, while simplified for brevity, is the foundation needed to create recombinant antibodies and proteins.

Recombinant Antibodies

Recombinant DNA technology has grown exponentially since it was first developed and has been shown to be invaluable in developing antibody therapeutics for human and animal use. Recombinant antibodies are utilized to treat a variety of illnesses ranging from cancer to rabies, and more than 130 different antibodies are currently in late-stage clinical trials (The Antibody Society). The popularity and success of recombinant antibodies is due to the advantages they have over hybridoma derived monoclonal antibodies.

  • Ensured reproducibility
    A recombinant antibody is absolutely defined by amino acid sequence, ensuring batch-to-batch reproducibility.
  • Biological definition
    Research has shown that more than 30% of traditional hybridoma-derived antibodies are not actually monoclonal, leading to problems with binding specificity, affinity, and reproducibility. In contrast, recombinant antibodies are truly biologically defined, with no variation in heavy or light chains; you know exactly what is in each and every vial.
  • High purity
    Recombinant antibodies are expressed in a chemically defined, serum-free mammalian expression system, eliminating contamination from serum components and resulting in highly pure antibodies with low endotoxin levels.
  • Added antibody value
    Recombinant technology enables antibody engineering and the production of custom antibodies. Novel formats can extend antibody usefulness and open up new experimental possibilities for in vitro and in vivo use.
  • Security
    Unlike hybridomas, recombinant antibodies are not susceptible to contamination, genetic drift, or accidental loss. With a known sequence, recombinant antibodies can always be reproduced for further use.

Recombinant Proteins

Much like recombinant antibodies, recombinant proteins offer many advantages in terms of customization, ensured reproducibility, and purity. The ability to customize and manufacture indefinitely makes recombinant technology the popular choice for producing proteins for therapeutic use. Two notable examples of this are Human Growth Hormone and insulin.

  • Human Growth Hormone (hGh): Recombinant DNA technology allows for the production of hGh to treat growth hormone deficiency in children.
  • Insulin: Prior to recombinant technology, insulin from cattle and pigs was used to treat diabetes. While it saved many lives, it would cause allergic reactions in some patients. The first recombinantly produced insulin came on the market in 1982 and since then, numerous forms have been developed to treat diabetes.

Recombinant DNA in Other Industries

Recombinant technology can be found in industries other than healthcare, including in food and agriculture. Chymosin is a protease used to make cheese and is traditionally found in rennet extracted from calf stomachs. Recombinant chymosin can be produced using bacteria or yeast, making cheese production more efficient and vegetarian friendly. In the agricultural industry, recombinant technology is being utilized to gene edit crops, such as corn and soybeans, to be resistant to herbicides.

The Future of Recombinant Technology

Recombinant DNA technology is responsible for some remarkable and life-changing breakthroughs in health and medicine, with a great possibility of even more discoveries to come. From drought resistant crops to immunotherapies to treat cancer, recombinant DNA holds promise for a healthier and more sustainable future.

Latest News

Upcoming Events

Please join us at the following conferences and events. Stop by our booth, or get in touch to arrange a meeting.

See All Dates

Next Event:

ADLM – Booth #1245

28th July - 1st August 2024

Chicago, Illinois

Antibody Sequencing and High Throughput Production for Hybridoma Libraries

Read more

Recombinant DNA Technology: An Overview

Read more