Scientists at the University of Bath have discovered a new type of cell in human embryos that has a “program” to self-destruct during the first few days of development. This discovery may help to understand the processes that take place in the first days of an embryo’s life and how they affect the health of the future child.
The researchers analyzed gene activity data from 5-day-old embryonic cells and found that about a quarter of the cells did not fit the profile of any of the known cell types. Upon further investigation, they found that these cells contained young mobile elements, or transposons, which can travel across the genome and cause DNA damage.
However, a longer observation showed that the progeny of these cells have DNA damage and undergo a process of programmed cell death. According to the authors of the study, this is a manifestation of DNA protection. “Although we (the human body) try to suppress these transposons by any means possible, at a very early stage of development they are active in some cells, probably because we cannot establish genetic protection fast enough,” the authors say.
The key cells that will become embryos do not contain transposons, but instead express a virus-like gene called human endogenous virus H. It helps suppress young mobile elements in the main cell mass.
This discovery may help in understanding the processes that take place in the early days of an embryo’s life and how they affect the health of the unborn child. It could also lead to the development of new treatments for diseases associated with DNA damage.