Recombinant Viruses

Recombinant Viruses

Subject: Science & Tech.

Context- Recombination of two virus variants seen since 2020. In the case of SARS-CoV-2 virus, such recombination has been seen right after the Alpha variant emerged.

Concept-

Mutation:

• A mutation means a change in the genetic sequence of the virus.
• In the case of SARS-CoV-2, which is an Ribonucleic acid (RNA) virus, a mutation means a change in the sequence in which its molecules are arranged.
  • RNA is an important biological macromolecule that is present in all biological cells, Principally involved in the synthesis of proteins, carrying the messenger instructions from Deoxyribonucleic Acid (DNA), which is an organic chemical that contains genetic information and instructions for protein synthesis. It is found in most cells of every organism.
• A mutation in an RNA virus often happens when the virus makes a mistake while it is making copies of itself.
• Mutations are a natural phenomenon when viruses replicate.
• Generally, RNA viruses have a higher rate of mutations compared with DNA viruses.
• However, unlike other RNA viruses, coronaviruses have fewer mutations. This is because coronaviruses have a genetic “proofreading mechanism” that corrects some of the errors made during replication.

Recombinant Viruses:

• Changes to the virus through natural collection of mutations involves small changes in the genome. But like in the case of influenza viruses, when a person is simultaneously infected with two different SARS-CoV-2 variants, genetic material from one variant can get mixed with the other. This is called recombination.
• Recombinant viruses are those that are generated to incorporate modification(s) introduced into a specific gene/locus (or multiple loci) of the viral genome.
• A recombinant virus may occur naturally or be produced by recombining pieces of DNA using recombinant DNA technology.
• Currently, various types of recombinant viruses including adenovirus, adeno-associated virus, lentivirus and retrovirus have been utilized in the development of vaccines and gene delivery vectors and various diseases therapy.
• Acting as vectors, recombinant viruses are able to efficiently deliver and promote high levels of transgene expression in a wide range of host cell.
• Cancer therapy based on recombinant viruses is currently being extensively investigated and shows great promise in the preclinical and clinical study.

Features of Recombinant Virus:

• High transfection efficiency
• A wide range of host cells
• High level of gene expression
• High packaging capacity for gene delivery