Sunday, March 6, 2016

Further evidence that mimivirus is a fourth domain

Hi guys,

A new paper was just published showing a CRISPR like defense system is present in the mimivirus against virophage that the paper has named a "MIMIVIRE system." CRISPRs as they are currently known, are found in 48% of bacteria and 80% of archaea. The system is capable of recognizing a destroying invading phage DNA that has attached to host DNA. In the paper, strains A, B, and, C of mimivirus were infected with virophage Zamilon, a new virophage that is associated with the strains of mimivirus that causes the mimivirus to stop copying itself. Strain A was not affected by Zamilon and the paper shows a set of proteins made by strain A that was similar to CRISPR system. The paper argues that a defense system like this is unusual to find in a virus as it is more similar to other microbes, suggesting that the mimivirus has gone through a separate evolutionary path, further bolstering the possibility that they belong in a fourth domain branch.

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature17146.html

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