In cancer, an embryonic gene-silencing mechanism gone awry

October 4, 2012

There are some genes that are only activated in the very first days of an embryo's existence. Once they have accomplished their task, they are shut down forever, unlike most of our genes, which remain active throughout our lives. EPFL scientists have unveiled part of this strange mechanism. The same process, accidentally initiated later in life, could be responsible for many kinds of cancer. The discovery is described in a recent article in the journal Cell Reports.

The researchers identified a group of proteins that play a key role in this phenomenon. They bind to a DNA sequence near the gene, and substitute one DNA element for another, essentially "marking" the sequence. This phenomenon is known as "methylation." Once the marker is in place, the recognizes the sign and maintains the gene in a dormant state.

"It's an extremely elegant mechanism. The genes are needed right at the beginning of embryonic development, but rather than deactivate them every time a cell divides, the job is done in one fell swoop, once the genes are no longer required," explains EPFL professor Didier Trono, who co-authored the article. "This process is also involved in the control of , which make up almost half of our genome, and must be inactivated very early in development."

This gene-silencing mechanism, which normally takes place in a several-day-old embryo, can also occur accidentally later in life. In many , certain genes have been marked by methylation; they have been silenced. If, for example, the gene responsible for controlling cell division has been methylated, the consequences are all too easy to imagine. "The embryonic process, which is designed to silence certain genes, can be fortuitously reactivated, leading to the formation of ."

It is still not understood why the process stops after the first days of , even though many of the active proteins continue to be expressed in the cell, says Trono. "If we can figure out how this cellular clock works, then we would perhaps be able to understand how the mechanism is reactivated later, leading to the development of cancer."

Explore further: Scientists complete first mapping of molecule found in human embryonic stem cells

Related Stories

Scientists complete first mapping of molecule found in human embryonic stem cells

July 21, 2011
Stem cell researchers at UCLA have generated the first genome-wide mapping of a DNA modification called 5-hydroxymethylcytosine (5hmC) in embryonic stem cells, and discovered that it is predominantly found in genes that are ...

Study discovers genetic pathway impacting the spread of cancer cells

May 3, 2012
In a new study from Lawson Health Research Institute, Dr. Joseph Torchia has identified a new genetic pathway influencing the spread of cancer cells. The discovery of this mechanism could lead to new avenues for treatment.

Recommended for you

Genome analysis with near-complete privacy possible, say researchers

August 17, 2017
It is now possible to scour complete human genomes for the presence of disease-associated genes without revealing any genetic information not directly associated with the inquiry, say Stanford University researchers.

Science Says: DNA test results may not change health habits

August 17, 2017
If you learned your DNA made you more susceptible to getting a disease, wouldn't you work to stay healthy?

Genetic variants found to play key role in human immune system

August 16, 2017
It is widely recognized that people respond differently to infections. This can partially be explained by genetics, shows a new study published today in Nature Communications by an international collaboration of researchers ...

Phenotype varies for presumed pathogenic variants in KCNB1

August 16, 2017
(HealthDay)—De novo KCNB1 missense and loss-of-function variants are associated with neurodevelopmental disorders, with or without seizures, according to a study published online Aug. 14 in JAMA Neurology.

Active non-coding DNA might help pinpoint genetic risk for psychiatric disorders

August 16, 2017
Northwestern Medicine scientists have demonstrated a new method of analyzing non-coding regions of DNA in neurons, which may help to pinpoint which genetic variants are most important to the development of schizophrenia and ...

Evolved masculine and feminine behaviors can be inherited from social environment

August 15, 2017
The different ways men and women behave, passed down from generation to generation, can be inherited from our social environment - not just from genes, experts have suggested.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.