Context:
Researchers believe that Retroviruses could offer insights into treating diseases like cancer
Key highlights:
- A retrovirus is a type of virus that uses RNA (ribonucleic acid) as its genetic material.
- They can integrate into and modify the genomes of their host organisms. Retroviruses have an RNA genome that can reverse transcribe into DNA and insert into the host’s genome.
- This process can sometimes result in ‘zombie’ regions in the host’s DNA, known as endogenous retroviruses (ERVs). ERVs represent footprints of previous retroviral infections and have been termed “fossil viruses”.
- Endogenous retroviruses (ERVs) are a significant part of the human genome, making up about 8%. Although most ERVs are inactive, they have left genetic “fossils” that researchers believe have influenced human evolution and could offer insights into treating diseases like cancer.
The Unique Mechanism of Retroviruses
- Infection: The virus enters a host cell.
- Integration into Host DNA: Retroviruses reverse transcribe their RNA genome into DNA. The enzyme integrase helps integrate the reverse-transcribed viral DNA into the host’s DNA by acting like glue to bind the two genomes together.
- Formation of Provirus: Once integrated, the viral DNA is called a provirus. The provirus has all the necessary components to function within the host cell.
- Hijacking Host Cells: The virus effectively hijacks the host’s cellular machinery. Infected cells are turned into virus-making factories, producing new viral particles that can infect other cells.
The Discovery of Human Retroviruses
- The human retrovirus, the human T lymphotropic virus (HTLV), was first discovered in 1980 by Robert C. Gallo and his team.
- This virus was linked to certain types of cancers, like cutaneous T-cell lymphoma.
- Just a few years later, in 1983, Françoise Barré-Sinoussi and Luc Montagnier discovered the retrovirus responsible for AIDS, later named the human immunodeficiency virus (HIV).
- These discoveries highlighted the profound impact retroviruses could have on human health and disease.
ERVs and Cancer
- In cancer research, a specific ERV element called LTR10 has been linked to colorectal cancer.
- Integrated into the human genome around 30 million years ago, LTR10 may affect tumor formation through its regulation by epigenetic marks.
- These findings suggest that ERVs can contribute to cancer development and highlight the potential for targeting these elements in cancer therapies.
Future Prospects
- Understanding the roles of ERVs in human biology could lead to new treatments for diseases like cancer and offer insights into regenerative and personalised medicine.
- The study of ERVs not only deepens our knowledge of human evolution but also opens up new avenues for improving human health.