Featured Research

from universities, journals, and other organizations

Ancient Retrovirus Is Resurrected

Date:
March 1, 2007
Source:
Rockefeller University
Summary:
Retroviruses have been around longer than humanity itself. In fact, the best-known family member, HIV, is a relative youngster, with its first known human infections occurring sometime in the mid-20th century. But although many retroviruses went extinct hundreds of thousands or millions of years ago, researchers studying the pathogens don't use the traditional tools of paleontologists: They need look only as far as our own DNA.

Budding system. Human cells expressing structural proteins from the resurrected retrovirus, HERV-KCON, build retrovirus-like particles and release them from the cell membrane, just as cells infected with a true retrovirus do. (Credit: Image courtesy of Rockefeller University)
Credit: Image courtesy of Rockefeller University

Retroviruses have been around longer than humanity itself. In fact, the best-known family member, HIV, is a relative youngster, with its first known human infections occurring sometime in the mid-20th century.

But although many retroviruses went extinct hundreds of thousands or millions of years ago, researchers studying the pathogens don’t use the traditional tools of paleontologists: They need look only as far as our own DNA. Retroviruses infect cells and replicate by inserting their DNA into their host cell’s genome. If that cell happens to be a germ cell, such as a sperm, an egg or their precursors, then the retroviral DNA is inherited by offspring just like a normal gene. Humans have many defunct retroviruses deposited in our DNA, remnants of ancient retroviruses that replicated in our ancestors millions of years ago. Now, researchers have brought one of those retroviruses back to life.

“In our DNA, there’s a fossil record of retroviruses that used to infect us,” says Paul Bieniasz, associate professor and head of the Laboratory of Retrovirology at Rockefeller University and the Aaron Diamond AIDS Research Center. In fact, about eight percent of human DNA is made up of retroviral sequences. Bieniasz and Youngnam Lee, a graduate student in the Bieniasz lab, have excavated some of that DNA and — in an attempt to better understand how humans and retroviruses co-evolved — they have resurrected an ancient retrovirus, one that can create new viral particles and infect human cells. They describe their work in a paper published by PLoS Pathogens last month.

The extinct retroviruses embedded in our DNA can’t reproduce because of mutations in one or more of their genes. The younger of these human endogenous retroviruses (or HERVs) have fewer changes, and judging by the paucity of genetic alterations, at least one subfamily — HERV-K — was likely still active less than a few hundred thousand years ago. Different members of this subfamily have slightly different mutations. “But as of a few months ago,” Bieniasz says, “there was no replication-competent form of this virus.”

To eliminate those mutations that kept HERV-K from replicating, the two researchers deduced a genetic sequence that was a consensus of 10 different HERV-K proviruses and synthesized the whole viral genome from scratch. Then, they took that sequence (which they dubbed HERV-KCON) and inserted it into cultured human cells to see if it would result in the creation of HERV-K structural proteins. Their consensus sequence resulted in not only functional proteins, but in a retrovirus that was capable of creating new viral particles and integrating itself into a host cell’s genome. “This is the first time this has been done with a viral genome that was effectively dead, and now is alive — or at least has all the functions that suggest it should replicate,” Bieniasz says.

The project began, Lee says, because certain human and non-human primate cells produce proteins that appear to block HIV from replicating. “And the question is where did the proteins come from?” she asks. “By studying these extremely old viruses, we can tap into what happened in our ancestors millions and millions of years ago.”

Citation: Public Library of Science Pathogens 3(1): e10 (January 26, 2007)


Story Source:

The above story is based on materials provided by Rockefeller University. Note: Materials may be edited for content and length.


Cite This Page:

Rockefeller University. "Ancient Retrovirus Is Resurrected." ScienceDaily. ScienceDaily, 1 March 2007. <www.sciencedaily.com/releases/2007/02/070227213714.htm>.
Rockefeller University. (2007, March 1). Ancient Retrovirus Is Resurrected. ScienceDaily. Retrieved August 22, 2014 from www.sciencedaily.com/releases/2007/02/070227213714.htm
Rockefeller University. "Ancient Retrovirus Is Resurrected." ScienceDaily. www.sciencedaily.com/releases/2007/02/070227213714.htm (accessed August 22, 2014).

Share This




More Health & Medicine News

Friday, August 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Two US Ebola Patients Leave Hospital Free of the Disease

Two US Ebola Patients Leave Hospital Free of the Disease

AFP (Aug. 21, 2014) Two American missionaries who were sickened with Ebola while working in Liberia and were treated with an experimental drug are doing better and have left the hospital, doctors say on August 21, 2014. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
American Ebola Patients Released: What Cured Them?

American Ebola Patients Released: What Cured Them?

Newsy (Aug. 21, 2014) It's unclear whether the American Ebola patients' recoveries can be attributed to an experimental drug or early detection and good medical care. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins