Wednesday, October 1, 2014

"Melting" DNA for Infection Efficiency?

As we all learned in class, the insertion of viral genetic material is essential for host cell infection. One way that viruses insert their viral genome into cells is by direct injection. For humans, our DNA is tightly wound around histones in order to better condense the long strands of information. Similarly, in DNA viruses, DNA is often packed into condensed structures. This condensing of DNA has been shown to result in the state of the genetic material being a very much solid, crystalline structure. This should make it quite difficult for a virus to inject its genetic material into cells at the high speeds that they are known to do.

How does a virus get around this problem?

Recent research out of Carnegie Mellon University has shown that at 37oC, which is the average temperature of the human body, DNA in viruses is capable of "melting" and transitioning into a liquid form. This liquid state of the DNA makes injection of the genetic material a more efficient process. Imagine trying to insert a chunk of highly structured crystal past a membrane versus injection of a fluid.

These researchers have found this DNA state transition to be true for not only bacteriophages that infect E.coli, but also for the herpes simplex 1 virus that infects humans.

All in all, this recent discovery could mean new directions for how antiviral drugs are designed. By preventing this transition of DNA from solid to a more liquid state, it is potentially possible to reduce efficiency of injection of viral material into the host cell, thus reducing efficiency of infection!

-Anna Duan

http://www.futurity.org/dna-viruses-phase-transition-775052/

http://www.pnas.org/content/early/2014/09/29/1321637111.abstract

http://www.rsc.org/chemistryworld/2014/10/viruses-melt-glassy-solid-dna




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