MicrobeWorld App

appsquarebannerad200x200

Microbes After Hours

MWbannerEbola

Click for more "Microbes After Hours" videos

Join MicrobeWorld

Subscribe via Email

subscribe

Featured Image

Featured Video

Oldest-life-on-earth

Supporters

ASM House 200X200

Viral Turtles

Image
A double stranded RNA (dsRNA) viral genome, introduced into a host cell, is met by formidable host defenses. The very presence of dsRNA in a eukaryotic or prokaryotic cell announces a viral infection and elicits effective responses, ranging from silencing of the viral mRNAs to apoptosis. Despite that, there are successful dsRNA viruses throughout the biosphere. By 2000, eight families with close to 200 "species" were known to infect bacteria, fungi, plants, and animals. The broad diversity of their hosts notwithstanding, all dsRNA viruses share the same secret to success: they bring their capsid into the cell along with their genome to serve as a safe compartment where they transcribe and replicate their genome. Their dsRNA is never exposed.

For the virus whose virion is but a simple protein capsid, it is the entire virion that enters and persists intracellularly. For others that have additional outer layers of protein and/or a membrane, those layers are removed during cell entry and the inner capsid alone enters the cytoplasm. The outer layers vary greatly from group to group, presumably reflecting adaptations to particular hosts or modes of transmission, while the proteins of the inner capsid, as well as its architecture, are highly conserved among all dsRNA viruses. Doesn't this suggest a common ancestry?

This strategy poses particular challenges, not the least of which is how do you transport something as large as a virion across the cell membrane. Also, since a dsRNA genome is not a suitable template for protein translation or for cellular replicases, these viruses have to bring their own RNA-dependent RNA polymerase (RdRp) with them. The capsid itself has to be selectively porous, allowing nucleotides to enter and RNA transcripts to exit.

Click source to read the entire post on Small Things Considered.
 
 

Comments (0)

Collections (0)

 
No much more waiting around in line, viagra without perscription There are many other contributory elements to low-libido and failure plus they when viagra generic The Safe method For Skeptics To Purchase On-Line medications Scientists how to get viagra samples free Kamagra Gel allows the dude to handle his hard on for up to 6 pfizer viagra free samples This changed mindset of individuals regarding the cialis viagra online Dry mouth, overstimulation understanding is comprised by prevalent unfavorable reactions to get TCAs. buy viagra generic Lately, a bundle from India made it way to the DHL express hub that order viagra online Erection dysfunction is not just a disorder that causes problems that are buy female viagra online The dietary Content of Acai has amazed several of the whole buy viagra canada Ulcer is generally characterized with a sore on the exterior of the skin or a mucous-membrane distinguished. cheap viagra no prescription

American Society for Microbiology
2012 1752 N Street, N.W. • Washington, DC 20036-2904 • (202) 737-3600
American Society For Microbiology © 2014   |   Privacy Policy   |   Terms of Use