Nav: Home

Viruses in the genome important for our brain

January 12, 2017

Over millions of years retroviruses have been incorporated into our human DNA, where they today make up almost 10 per cent of the total genome. A research group at Lund University in Sweden has now discovered a mechanism through which these retroviruses may have an impact on gene expression. This means that they may have played a significant role in the development of the human brain as well as in various neurological diseases.

Retroviruses are a special group of viruses including some which are dangerous, such as HIV, while others are believed to be harmless. The viruses studied by Johan Jakobsson and his colleagues in Lund are called endogenous retroviruses (ERV) as they have existed in the human genome for millions of years. They can be found in a part of DNA that was previously considered unimportant, so called junk-DNA -- a notion that researchers have now started to reconsider.

"The genes that control the production of various proteins in the body represent a smaller proportion of our DNA than endogenous retroviruses. They account for approximately 2 per cent, while retroviruses account for 8-10 per cent of the total genome. If it turns out that they are able to influence the production of proteins, this will provide us with a huge new source of information about the human brain", says Johan Jakobsson.

And this is precisely what the researchers discovered. They have determined that several thousands of the retroviruses that have established themselves in our genome may serve as "docking platforms" for a protein called TRIM28. This protein has the ability to "switch off" not only viruses but also the standard genes adjacent to them in the DNA helix, allowing the presence of ERV to affect gene expression.

This switching-off mechanism may behave differently in different people, since retroviruses are a type of genetic material that may end up in different places in the genome. This makes it a possible tool for evolution, and even a possible underlying cause of neurological diseases. In fact, there are studies that indicate a deviating regulation of ERV in several neurological diseases such as ALS, schizophrenia and bipolar disorder.

Two years ago, Johan Jakobsson's team showed that ERV had a regulatory role in neurons specifically. However, this study was conducted on mice, whereas the new study - published in the journal Cell Reports -- was made using human cells.

The differences between mice and humans are particularly important in this context. Many of the retroviruses that have been built into the human DNA do not exist in species other than humans and our closest relatives -- gorillas and chimpanzees. They seem to have incorporated themselves into the genome some 35-45 million years ago, when the evolutionary lineage of primates was divided between the Old and New World.

"Much of what we know about the overall development of the brain comes from the fruit fly, zebrafish and mouse. However, if endogenous retroviruses affect brain function, and we have our own set of these ERV, the mechanisms they affect may have contributed to the development of the human brain", says Johan Jakobsson.
-end-


Lund University

Related Dna Articles:

Penn State DNA ladders: Inexpensive molecular rulers for DNA research
New license-free tools will allow researchers to estimate the size of DNA fragments for a fraction of the cost of currently available methods.
It is easier for a DNA knot...
How can long DNA filaments, which have convoluted and highly knotted structure, manage to pass through the tiny pores of biological systems?
How do metals interact with DNA?
Since a couple of decades, metal-containing drugs have been successfully used to fight against certain types of cancer.
Electrons use DNA like a wire for signaling DNA replication
A Caltech-led study has shown that the electrical wire-like behavior of DNA is involved in the molecule's replication.
Switched-on DNA
DNA, the stuff of life, may very well also pack quite the jolt for engineers trying to advance the development of tiny, low-cost electronic devices.
Researchers are first to see DNA 'blink'
Northwestern University biomedical engineers have developed imaging technology that is the first to see DNA 'blink,' or fluoresce.
Finding our way around DNA
A Salk team developed a tool that maps functional areas of the genome to better understand disease.
A 'strand' of DNA as never before
In a carefully designed polymer, researchers at the Institute of Physical Chemistry of the Polish Academy of Sciences have imprinted a sequence of a single strand of DNA.
Doubling down on DNA
The African clawed frog X. laevis genome contains two full sets of chromosomes from two extinct ancestors.
'Poring over' DNA
Church's team at Harvard's Wyss Institute for Biologically Inspired Engineering and the Harvard Medical School developed a new electronic DNA sequencing platform based on biologically engineered nanopores that could help overcome present limitations.

Related Dna Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".