Featured Research

from universities, journals, and other organizations

Virus grows tube to insert DNA during infection, then sheds it

Date:
December 15, 2013
Source:
Purdue University
Summary:
Researchers have discovered a tube-shaped structure that forms temporarily in a certain type of virus to deliver its DNA during the infection process, and then dissolves after its job is completed.

Researchers have discovered a tube-shaped structure that forms temporarily in a certain type of virus to deliver its DNA during the infection process and then dissolves after its job is completed. The virus is pictured here infecting an E. coli cell. The tube attaches to the cell's inner and outer membranes, bridging the "periplasmic space" in between.
Credit: Purdue University image/Lei Sun

Researchers have discovered a tube-shaped structure that forms temporarily in a certain type of virus to deliver its DNA during the infection process and then dissolves after its job is completed.

The researchers discovered the mechanism in the phiX174 virus, which attacks E. coli bacteria. The virus, called a bacteriophage because it infects bacteria, is in a class of viruses that do not contain an obvious tail section for the transfer of its DNA into host cells.

"But, lo and behold, it appears to make its own tail," said Michael Rossmann, Purdue University's Hanley Distinguished Professor of Biological Sciences. "It doesn't carry its tail around with it, but when it is about to infect the host it makes a tail."

Researchers were surprised to discover the short-lived tail.

"This structure was completely unexpected," said Bentley A. Fane, a professor in the BIO5 Institute at the University of Arizona. "No one had seen it before because it quickly emerges and then disappears afterward, so it's very ephemeral."

Although this behavior had not been seen before, another phage called T7 has a short tail that becomes longer when it is time to infect the host, said Purdue postdoctoral research associate Lei Sun, lead author of a research paper to appear in the journal Nature on Dec. 15.

The paper's other authors are University of Arizona research technician Lindsey N. Young; Purdue postdoctoral research associate Xinzheng Zhang and former Purdue research associate Sergei P. Boudko; Purdue assistant research scientist Andrei Fokine; Purdue graduate student Erica Zbornik; Aaron P. Roznowski, a University of Arizona graduate student; Ian Molineux, a professor of molecular genetics and microbiology at the University of Texas at Austin; Rossmann; and Fane.

Researchers at the BIO5 institute mutated the virus so that it could not form the tube. The mutated viruses were unable to infect host cells, Fane said.

The virus's outer shell, or capsid, is made of four proteins, labeled H, J, F and G. The structures of all but the H protein had been determined previously. The new findings show that the H protein assembles into a tube-shaped structure. The E. coli cells have a double membrane, and the researchers discovered that the two ends of the virus's H-protein tube attach to the host cell's inner and outer membranes.

Images created with a technique called cryoelectron tomography show this attachment. The H-protein tube was shown to consist of 10 "alpha-helical" molecules coiled around each other. Findings also showed that the inside of the tube contains a lining of amino acids that could be ideal for the transfer of DNA into the host.

"This may be a general property found in viral-DNA conduits and could be critical for efficient genome translocation into the host," Rossmann said.

Like many other viruses, the shape of the phiX174 capsid has icosahedral symmetry, a roughly spherical shape containing 20 triangular faces.


Story Source:

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


Journal Reference:

  1. Lei Sun, Lindsey N. Young, Xinzheng Zhang, Sergei P. Boudko, Andrei Fokine, Erica Zbornik, Aaron P. Roznowski, Ian J. Molineux, Michael G. Rossmann, Bentley A. Fane. Icosahedral bacteriophage ΦX174 forms a tail for DNA transport during infection. Nature, 2013; DOI: 10.1038/nature12816

Cite This Page:

Purdue University. "Virus grows tube to insert DNA during infection, then sheds it." ScienceDaily. ScienceDaily, 15 December 2013. <www.sciencedaily.com/releases/2013/12/131215160906.htm>.
Purdue University. (2013, December 15). Virus grows tube to insert DNA during infection, then sheds it. ScienceDaily. Retrieved April 18, 2014 from www.sciencedaily.com/releases/2013/12/131215160906.htm
Purdue University. "Virus grows tube to insert DNA during infection, then sheds it." ScienceDaily. www.sciencedaily.com/releases/2013/12/131215160906.htm (accessed April 18, 2014).

Share This



More Plants & Animals News

Friday, April 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Vermont Goat Meat Gives Refugees Taste of Home

Vermont Goat Meat Gives Refugees Taste of Home

AP (Apr. 18, 2014) Dairy farmers and ethnic groups in Vermont are both benefiting from a unique collaborative effort that's feeding a growing need for fresh and affordable goat meat. (April 18) Video provided by AP
Powered by NewsLook.com
The Great British Farmland Boom

The Great British Farmland Boom

Reuters - Business Video Online (Apr. 17, 2014) Britain's troubled Co-operative Group is preparing to cash in on nearly 18,000 acres of farmland in one of the biggest UK land sales in decades. As Ivor Bennett reports, the market timing couldn't be better, with farmland prices soaring over 270 percent in the last 10 years. Video provided by Reuters
Powered by NewsLook.com
Flamingo Frenzy Ahead of Zoo Construction

Flamingo Frenzy Ahead of Zoo Construction

AP (Apr. 17, 2014) With plenty of honking, flapping, and fluttering, more than three dozen Caribbean flamingos at Zoo Miami were rounded up today as the iconic exhibit was closed for renovations. (April 17) Video provided by AP
Powered by NewsLook.com
Change of Diet Helps Crocodile Business

Change of Diet Helps Crocodile Business

Reuters - Business Video Online (Apr. 16, 2014) Crocodile farming has been a challenge in Zimbabwe in recent years do the economic collapse and the financial crisis. But as Ciara Sutton reports one of Europe's biggest suppliers of skins to the luxury market has come up with an unusual survival strategy - vegetarian food. Video provided by Reuters
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