Junk DNA Can “Sense” Viral Infection –New Discovery

 

                           6a00d8341bf7f753ef015392961df3970b.jpg

 

In molecular biology, "junk" DNA is a collective label for the portions of the DNA sequence of a chromosome or a genome for which no function has yet been identified –until now. About 98.5% of the human genome has been designated as "junk", including most sequences within introns and most intergenic DNA.


While much of this sequence is probably an evolutionary artifact that appeared to serve no present-day purpose, in fact, recent studies have suggested functions for certain portions of what has been called junk DNA. Moreover, the conservation of some "junk" DNA over many millions of years of evolution may imply an essential function. The "junk" label is therefore recognized as something of a misnomer, and many prefer the more neutral term "noncoding DNA."

Now scientists have learned that non-coding RNA (ncRNA) — RNA molecules that do not translate into proteins — play a crucial role in cellular function. Mutations in ncRNA are associated with a number of conditions, such as cancer, autism, and Alzheimer's disease.

Through the use of "deep sequencing," a technology used to sequence the genetic materials of the human genome, Dr. Noam Shomron of Tel Aviv University's Sackler Faculty of Medicine has discovered that when infected with a virus, ncRNA gives off biological signals that indicate the presence of an infectious agent, known as a pathogen. 

These signals, which can include either the increase or decrease of specific ncRNA molecules within a cell, most likely have biological significance, Shomron says. "With the introduction of a pathogen, there is a reaction in both the coding and non-coding genes. By adding a new layer of information about pathogen and host interactions, we better understand the entire picture. And understanding the reactions of the ncRNA following infection by different viruses can open up the battle against all pathogens."

"If we see that the number of particular RNA molecules increases during a specific viral infection, we can develop treatments to stop or slow their proliferation," added Shomron.

The researchers conducted a blind study in which some cells were infected with the HIV virus and others were left uninfected. Using the deep sequencer, which can read tens of millions of sequences per experiment, they analyzed the ncRNA to discover if the infection could be detected in non-coding DNA materials. The researchers were able to identify with 100% accuracy both infected and non-infected cells — all because the ncRNA was giving off significant signals, explains Shomron.

The researchers believe that if an ncRNA molecule significantly manifests itself during infection by a particular pathogen, the pathogen has co-opted this ncRNA to help the pathogen devastate the host — such as the human body. To help the body fight off the infection, drugs that stop or slow the molecules' proliferation could be a novel and effective strategy.

This new finding allows researchers to develop treatments that attack a virus from two different directions at once, targeting both the coding and non-coding genetic materials, says Dr. Shomron. He suggests that ncRNA could prove to be the "Achilles heel" of pathogens.

Dr. Shomron and his team of researchers developed new software, called RandA, which stands for "ncRNA Read-and-Analyze," that performs ncRNA profiling and analysis on data generated through deep sequencing technology. It's this software that has helped them to uncover the features that characterize virus-infected cells.

The Daily Galaxy via aftau.org

error

"The Galaxy" in Your Inbox, Free, Daily