Protein Angst

Tuesday, February 01, 2005

Epidemics Can Induce Genetic Change

Scientist finds surprising links between arthritis and tuberculosis.

Included in this article is a bonus: the definition of "drug target." Because while you know the word "drug" and the word "target," putting them together causes them to lose all meaning. Lost in the editing room was the definition of another term with similar properties: "animal model." An animal model is a laboratory animal that has been given a disease of interest. By studying the disease — and the effects of drugs on it — in the animal, scientists can better understand the disease in humans.

alliterator asks:

"Here's my question: have you heard of the prion protein which causes the disease kuru and CJD (also known as Mad Cow Disease) and its relevance to the fact that perhistoric human civilization had widespread cannibalism?"

I have heard of prions, but I had never heard it related to prehistoric cannibalism. That's very interesting.

The funny thing about prions is they're infectious proteins. Normally, when you think of infection, you think of bacteria and viruses. Bacteria and viruses have nucleic acid, genetic material with which they can replicate and infect new cells. But a protein has no nucleic acids: it's made up of amino acids. It has no ability to replicate.

Instead, these rogue proteins seem to travel from cell to cell converting normal proteins into prions (not any protein, only the prion protein PrPC). And just like a viral infection, eventually the excess of prions causes the cell to die and release the infectious material into the open, where the disease can spread.

The initial prion is very much like a cult leader, travelling from city to city brainwashing new recruits. The recruits in turn spread the message.

I would like to look up more about prions and their relation to cannibalism, but until then, here are some useful sources for background information:

  • All About Prions
  • Prion Diseases
  • Prions: Puzzling Infectious Proteins
  • Do Prions Exist?


    • Cool. You're good at this.

      As for the prion protein's relationship with cannibalism, apparently kuru and CJD, which are caused by the prion protein, are spread only by eating the flesh of someone who was infected. Thus cows who eat other cows are infected with Mad Cow Disease (CJD) - and there was a tribe in New Guinea who traditionally ate their dead and was devastated by kuru.

      But apparently, being heterozygotes on codon 129 gives immunity for the disease and thus it was inferred that sometime in the past, there must have been a mass outbreak of kuru (thus mass cannibalism) and natural selection must have kicked in.

      Whew. Well, that's it for my book learning!


      By Anonymous Anonymous, at 1:51 PM  

    • Well. There you go. I had no idea about the link between RA and TB -- but it's *very* interesting. Is that publication #2 for you??? Way to go!


      By Anonymous Anonymous, at 9:21 AM  

    • Hello! This is Merinda's friend Christina, a science geek like yourself. Since I graduated in December, I've been suffering withdrawal from intelligent literature, so she was kind enough to send me a link to your blog, and to your article, to remedy this.

      I worked for one of my biology professors for a couple of years, at the time when Mad Cow Disease was first becoming news, and he was fascinated by prions, so I did a lot of research for him into the subject. It's very interesting stuff.

      You seem to have a talent for explaning things accurately and simply, without dumbing it up. I'm very impressed. Great job, Sunil!

      *Science geeky hugs*


      By Anonymous Anonymous, at 2:00 PM  

    • so, i read a google headline saying that the protections that zoos use to prevent inbreeding might not be so good after all. what's up with that?

      and what does that mean for the Royal Families (human)?

      the people demand to know!

      By Blogger daedal, at 3:39 AM  

    • You're smart AND you have sexy hair. Such an unbeatable combination. And I feel more educated now with the information and the learning and what not. You rock! You know this right? Because you should. You so should.

      By Blogger Syd/GP, at 12:01 PM  

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