By Isobel Williams via SWNS
A virus that infected the first animals hundreds of millions of years ago is now essential in human development, research has revealed.
The new study has found that DNA from the virus now plays a vital part in human embryo development, especially in the first hours of fertilization.
Between eight and 10 percent of the human genome comes from these so called ‘endogenous retroviruses’, but until now this DNA has been considered as junk.
Research from the Spanish National Cancer Research Center (CNIO) has now uncovered that this supposed junk DNA plays a part in the transition to pluripotency, when the oocyte or immature egg cell, goes from having two to four cells, which is vital in human development.
First author Sergio de la Rosa said: “Until recently, these viral remnants were considered to be ‘junk DNA’, genetic material that was unusable or even harmful.
“Intuitively, it was thought that having viruses in the genome could not be good.
“However, in recent years we are starting to realize that these retroviruses, which have co-evolved with us over millions of years, have important functions, such as regulating other genes.
“It’s an extremely active field of research.”
The research published in the journal Science Advances shows that this ancient virus, called the MERVL endogenous retrovirus, sets the pace in embryo development.
The process involves a gene called URI which was discovered years ago to stop embryo development in animals when it is deleted.
A protein called MERVL-gag, which comes from this animal retrovirus, has now been revealed to modulate the action of URI.
Dr. Nabil Djouder added: “It is a totally new role for endogenous retroviruses.
“We discovered a new mechanism that explains how an endogenous retrovirus directly controls pluripotency factors.
“Our findings reveal symbiotic co-evolution of endogenous retroviruses with their host cells in order to guarantee the smooth and timely progression of early embryonic development.”
