Hey y’all!

I hope everyone had a great Christmas break! It’s good to be blogging again! I did not have the chance to share the virus I researched in class, but I thought I would share it now. It is hands-down the coolest virus I have ever read about. It’s called the mimivirus and it infects amoeba. What is really interesting about this virus is the sheer size. It has a diameter of about 400 nm, which is the third largest capsid size ever discovered. It has an icosahedral shaped capsid, which contains lots of enzymes and the virus’ double stranded DNA genome.  The genome is large, at over a million base pairs! Its genes do not only code for the typical virus things, but also code for aminoacyl tRNA synthase, and other proteins involved in protein synthesis and metabolism.

What makes this virus even more incredible is how it replicates. After it is engulfed by the amoeba by receptor-mediated endocytosis, it uses its own enzymes to replicate its DNA and transcribe it to mRNA. Most dsDNA viruses send their DNA to the nucleus to be replicated and transcribed using the host’s mechanism, but the mimivirus uses its own. It has a viral core, which does not degrade in the host’s cytoplasm, that acts as the new nucleus of the cell. It has both RNA and DNA polymerases, which it uses in replication and transcription. After transcription, the virus uses the host’s ribosomes to make the necessary proteins for the capsid and enzymes inside the viral core. When more viral cores are made, those cores begin replication and transcription. This continues until the cell is lysed, releasing all of the new mimiviruses.

Crazy, right? This is one of the only known viruses that replicate in this manner!

If you want to know more about how the mimvirus works and how scientists discovered it, you should read this article:

http://www.pnas.org/content/107/13/5978.full