So almost exactly a year ago, Michael 'LiLo' Behe released his prized pig book, 'Edge of Evolution', where he stated, with utmost certainty, that HIV-1 'has not evolved'.
Yeah, that hasnt worked out too well for him.
Anyway, unlike Ivory Handed Creationists who dont lower themselves to doing anything as dirty as 'research', scientists have kept busy seeking out new proteins within our own bodies to explain some weird evolution in the Vpu gene of HIV-1. Turns out there is a component of the innate immune system that we didnt even know existed before we followed the trail of Vpus 'unimpressive' and 'pathetic' evolution-- tetherin. Tetherin is a way all of your cells can defend themselves against retroviruses (or wayward ERVs). It prevents progeny viruses from spreading-- they stay stuck to the infected cell. Neato!
Well, thats where we left those pathetic evilutionists desperately clinging to Darwinism three months ago. What have they done since?
Every so often, scientists get together at conferences to talk about their research. They can have colleagues critique what theyre doing, or help with new ideas on projects that have stalled. Conferences are like four straight days of concentrated geeky brainstorming.
My labmate just went to one of these at Cold Spring Harbor Laboratory.
And she got the lowdown on the latest in Vpu research for us!
Get this:
One group looked at tetherin in non-humans (common, you didnt think tetherin is only found in humans cause were Specially Created :P), Rhesus macaques, African green monkeys, and mice. They knocked out Vpu in HIV, and tried to infect cell lines from those animals. Then they added Vpu back to see if the non-human tetherins could be wiped out with Vpu, like what happens in humans:
"These non-human tetherins are capable of restricting HIV-1 release, but in contrast to the human protein, are not overcome by Vpu expression, demonstrating the exquisite species specificity that is a common feature of retroviral restriction factors."
HIV-1 Vpu is human tetherin specific!!!
Pfffff. Pathetic!
Those worthless evilutionists are going so far as to put more research into the origins of tetherin!
Another group looked at the functional abilities of tetherin:
"... we examined its (Vpu) ability to inhibit the release of a variety of virions derived from retroviruses that share little sequence homology. These included: HIV-1, SIVmac, SIVagm, EIAV, MLV, HERV-K, and PFV. Tetherin appears capable of restricting the release of every retrovirus that we have tested thusfar."
So Vpu is human tetherin specific, but human tetherin isnt HIV-1 specific. We didnt evolve this protein specifically in response to HIV-1...but HIV-1 sure evolved in response to us.
Very cool! Caint wait till these brainstorms get out into a publication!
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All the nifty virus stuff inspires me to a comment ERV style:
Perhaps you have heard of the cool Mimivirus. It is a scifi-virus! As the worlds largest virus, it is larger than some bacterias. It contains more protein-coding genes than some bacterias too.
Now more of the Mimivirus scifi life has been shown on film. It is a freakin' alien!
Normally, a virus is a syringe. It injects its genetic poison into the cell through a channel. The same channel that is used in virus assembly to load the new syringes back up with the poison.
But the Mimivirus doesn't do tiddly widdly needle puncures. After attaching to the poor victim, the wall of the capsid opens up as a frikkin' flower petal to rip the cell wall apart and push the virus innards in like so much stuffing! Scientists call the star shaped gate the Stargate.
And do baby Mimivirus pack their genome through the stargate and then close the petals as a nice christmas present for the next cell? Noo... It loads it up the backway.
Mimivirus isn't a poisonous syringe, it is a loaded gun. Look out amoebas, you don't want to meet a Mimivirus in a dark alley! Not even when trying out for the Alien cast.
Will it be possible to engineer mouse to have human tetherin instead of their native form?
Hooray — I haven't added anything new to the list for a while.
(takes deep breath, raises fist to the sky, throws head back)
"SCIIIEEEEEEEENCE!"
FondleTheKids may now resume her regular scheduled bleating. Phlegming can sing backup.
Is that by itself actually evidence that HIV-1 evolved Vpu in response to human tetherin? Maybe HIV-1 was just design very specifically to mess with Tetherin.
And now for the actually serious question: how different are the tetherin proteins across the different species? If I had to make a guess, I'd hazard that HIV-1 isn't the only retrovirus that's tried to do this sort of thing. We can presumably test that by looking at the different types of tetherin in the different species. We should see evidence of heavy selection pressure on tetherin. Is anyone looking for it?
Science: Getting things done since the fifteenth century.
Joshua, why should we see evidence of heavy selection pressure on tetherin? Look at the last paragraph of the post, specifically the sentence, "So Vpu is human tetherin specific, but human tetherin isnt HIV-1 specific." Differences between species of tetherin could simply occur due to genetic drift. Differences in Vpu between viruses specific to different species, on the other hand, do seem to display evidence of heavy selection pressure since they are specific to the tetherin of each species as well. I wouldn't jump to assume adaptionism in a gene before seeing evidence of it, and based on the novelty of tetherin I doubt we've seen much evidence yet (though correct me if I'm wrong!).
We "assume adaptationism" because tetherin in various species still appears to protect against retroviruses. If it drifted randomly there'd be no reason why it would continue to do so: at the very least there has to have been stabilizing selection. We don't know whether there has also been selection because of an "arms race" between tetherin and retroviruses in mammals, but it is a good and testable question.
Lilo!
I wonder if you are aware that in Australia, a lilo is a kind of inflatable mattress. You may use as a mattress, or toss it into a body of water to float on. So it's also a bag of air... but more useful than Behe.
Keep up the good fight against old liabehety, or is that liarbehety, either way works for me. Paleys bastard grandchildren must be stopped.