Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Infected for life

How the Herpes Simplex Virus Uses MicroRNA to Hide Out in Cells

Researchers at the University of Pennsylvania School of Medicine have discovered part of the reason why cold sores, caused by a herpes virus, come back again and again. The new study, published online last month in Nature, points to a small RNA molecule, called a microRNA (miRNA) as the culprit that keeps the latent virus-infected cell alive. These findings could one day lead to a new way to fight the virus and offers the first target for intervention in the latent infection.

A research team led by Nigel W. Fraser, PhD, Professor of Microbiology, has found that herpes simplex virus-1 (HSV-1), the virus that causes cold sores and ocular keratitis, produces an miRNA molecule. This miRNA is encoded by the Latency-Associated Transcript gene (LAT) in the viral genome and works through a process called RNA interference to prevent normal cell death or apoptosis. Thus, the latent viral infection is maintained for the lifetime of the individual because the latently infected cell does not die.

"Although miRNAs encoded by cellular genes are known to be an important mechanism for controlling gene expression, this is one of the first miRNA found to be encoded by a viral genome," says Fraser. "Our study helps show how HSV-1 can maintain a latent infection for the lifetime of an infected individual."

The LAT gene was discovered by Fraser and colleagues in 1984, but a protein product from this gene has never been found. This caused Fraser and his research team to hypothesize that LAT may work through an miRNA molecule, which is a small piece of the LAT gene. It interferes with the translation of two cell proteins that are required for cell death: TGF-b and SMAD-3. The LAT miRNA binds to specific sequences of messenger RNA from these two genes and causes them to be degraded. Thus, the amount of TGF-b and SMAD-3 protein is reduced in the cell and apoptosis is prevented. Because the latent virus is not producing any viral proteins the immune system of the infected individual cannot detect the infected cell.

Latent HSV-1 infections form in neuronal cells of the peripheral nervous system. When a latent infection is reactivated (by stress of many kinds), HSV-1 proteins are synthesized and new infectious virus particles are formed. These virus particles migrate along the neuronal axons to the epithelial cells of the skin. Viral growth in the skin, or other mucous membranes where nerves are found, causes cell damage and an immune reaction that results in a painful sore. Although the latency-to-reactivation process is not fully understood, it is known to involve stress, such as physical damage, ultraviolet light, hormones, or even fever.

Fraser is currently testing whether HSV-2, a relative of HSV-1 that causes genital herpes, also encodes an miRNA molecule in its LAT gene. "MiRNA may be a more general mechanism that latent viruses use to remain alive in the host cell," suggests Fraser.

Present treatments of HSV-1 rely on acyclovir-based drugs that target the viral polymerase and inhibit viral DNA replication during the acute infection. However, they do not target the latent infection, and thus cold sores return throughout the lifetime of the infected individual. Finding an miRNA that interacts with the cellular TGF-b pathway during latency offers the first target against the latent infection and offers a profoundly different approach to treatment, concludes Fraser.

Karen Kreeger | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht International team discovers novel Alzheimer's disease risk gene among Icelanders
24.10.2016 | Baylor College of Medicine

nachricht New bacteria groups, and stunning diversity, discovered underground
24.10.2016 | DOE/Lawrence Berkeley National Laboratory

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

New method increases energy density in lithium batteries

24.10.2016 | Power and Electrical Engineering

International team discovers novel Alzheimer's disease risk gene among Icelanders

24.10.2016 | Life Sciences

New bacteria groups, and stunning diversity, discovered underground

24.10.2016 | Life Sciences

More VideoLinks >>>