Slashdot Science: HIV-1 virion assembly

Thanks to everyone who sent me links to a new article so neat it got Slashdotted:

Imaging the biogenesis of individual HIV-1 virions in living cells

Researchers tagged a major structural protein of HIV-1 called 'Gag'** with a fluorescent protein. If you only put the instructions for Gag into cells (just the instructions, not any other HIV-1 proteins) lots and lots of Gags will get together to spontaneously form empty (and non-infectious) virions. This doesnt just happen with HIV-1-- lots of retroviruses, you can just give cells instructions for various Gag genes, and dummy 'viruses' will bud off.

So these guys gave cells instructions for HIV-1 Gag proteins tagged with a fluorescent protein, then sat and watched the surface of the cells for the appearance of dummy viruses, in real time. That last part is the novel aspect of this paper-- everyone knows youll eventually get virions, but whats cool is that they could image this happening, in real time! 5-6 minutes, viruses started appearing.

BUT!

Remember, they only gave their cells instructions for Gag! Its inappropriate to think that 5-6 minutes after a cell is infected, it will start producing viruses. Theyre missing entry, reverse transcription, trafficking, and integration steps, which would tack on additional time-- But as we say in science, those are 'further avenues for future research'. hehe!!

One thing I do want to add, which will make some readers lol, is this line:

When Gag was co-expressed with the viral protein Vpu, which reduces the surface tethering of virions and their subsequent appearance in late endosomes, the fraction of rapidly appearing/disappearing puncta fell both at early and late time points.

Translation: When they gave cells instructions for both Gag and Vpu, they got more viruses because they werent all tethered to the cell surface and being sucked up and degraded. LOL. Behe is such a loser.

**Ill make Gag the next entry in the 'Intro to ERVs' series :)

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I apologize for them. Its hard to get perdy piccies at that magnification, but I has two perdy piccies from wurk? Im killing these cells by putting a shitload of HIV-1 on em.

What cells are you killing there?

Its just a cell line-- U87 (CD4, CXCR4)-- Its a brain cell tumor that has been forced to express CD4 and CXCR4, the two receptors my virus needs to infect. Hehehehe Its not physiologically relevant, but they respond really well to my fluorescent proteins, so theyre fun for piccies :)

Theyre also dying real hard in those pics-- I put a ton of virus on em (MOI of '1'-- one infectious virus for each cell)