Context: Studies published on Human Endogenous Retrovirus Subfamily H (HERVH), a virus-like gene that helps maintain pluripotency, suggest that it has the potential to develop regenerative medicines.
Process of Embryonic Development:
- Inner Cell Mass (ICM): Before implantation in the mother's womb, cells in the early embryo organise into the inner cell mass. This mass of cells contains pluripotent cells.
- Committed Cells and HERVH Gene Expression: The gene HERVH is expressed in pluripotent stem cells within the inner cell mass. These cells are considered the "winners" because they commit to specific lineages and contribute to the development of the embryo.
- Non-Committed Cells and Transposon-Induced DNA Damage: Non-committed cells that do not express HERVH are found to express transposons, or jumping genes, which can cause DNA damage. The absence of HERVH leaves these cells vulnerable to uncontrolled transposon activity, leading to their elimination.
Human Endogenous Retrovirus Subfamily H (HERVH):
- HERVH is expressed in pluripotent stem cells, and its presence is associated with maintaining pluripotency, which is crucial for the development and formation of various tissues and organs in the body.
Role of HERVH in Prevention of Transposon Damage:
HERVH protects cells from the damage inflicted by transposons, also known as "jumping genes."
- Transposons can insert themselves into different regions of the genome, potentially causing DNA damage and cell death.
- HERVH expression, as identified in the study, serves to kickstart a protective mechanism, preventing the expression of transposons in most cells. Thus, safeguarding the integrity of the genetic material.
Role of HERVH in Regenerative Medicine:
- The study of the presence of HERVH and its potential application may contribute to the overall health and viability of the developing embryo.
- By understanding the dynamics of HERVH expression and its impact on cell survival, we may discover new avenues to improve fertility treatments and address challenges in conception.
- Reducing transposon activity in the early embryo, possibly by enhancing the expression of HERVH, could influence the fitness of the embryo, with potential applications in optimising in-vitro fertilisation (IVF) techniques.
Selection Arena:
The use of the term 'selection arena' in the study draws an analogy to the principles of natural selection observed in the animal kingdom. In the context of embryonic development, cells expressing HERVH are likened to the 'good' cells that will contribute to survival and embryonic development, while the cells that do not express HERVH are fated to be damaged and ultimately die.
Key Terms:
| Cell | A unit of life, the basic structural, functional, and biological unit of all known living organisms. Sperm Cell: Male reproductive cell. Egg or Ovum Cell: Female reproductive cell. Pluripotent Cell: A cell that has the ability to differentiate into many cell types.  |
| Zygote | The cell formed by the fusion of two gametes (sperm and egg), which contains the full set of chromosomes (half from each parent). |
| Implantation | The process by which the developing embryo embeds itself into the lining of the uterus. |
| Pluripotency | Pluripotency is the ability of a cell to differentiate into a wide range of cell types. |
| Differentiation | The process by which cells become specialised and distinct from one another. |
| Inner cell mass | The group of cells inside the blastocyst (an early stage of the embryo) that will give rise to the embryo. |
| Placenta | An organ that develops in the uterus during pregnancy, providing oxygen and nutrients to the developing foetus. |
| HERVH | A gene expressed in pluripotent stem cells, playing a role in maintaining pluripotency. |
| Transposons (Jumping genes) | DNA sequences that can move or "jump" to different positions within the genome. |