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From: werner@aecom.yu.edu (Craig Werner)
Newsgroups: sci.bio
Subject: Re: What ever happened to PRIONS ???  (scrapie, C-J, BSE)
Message-ID: <2587@aecom.yu.edu>
Date: 14 Nov 89 04:30:00 GMT
References: <23936@cup.portal.com> <13163@eerie.acsu.Buffalo.EDU>
Organization: Albert Einstein Coll. of Med., NY
Lines: 47

In article <13163@eerie.acsu.Buffalo.EDU>, dmark@acsu.Buffalo.EDU (David Mark) writes:
> In article <23936@cup.portal.com> mmm@cup.portal.com (Mark Robert Thorson) writes:
> 
> >SCIENTIFIC AMERICAN published an article.  What is the current status
> >of prions?  Has the theory been discredited or what?
> 

	I just glanced at the headline, but it appears that somebody
working on normal brain function just cloned the prion gene, not that
he intended to.
	Let me explain:  prions, proteinaceous infectious -ons, are
encoded for by cellular genes.  They show strain specificity depending
not on where you get the original isolate from but rather what gets
infected.  It is clearly infectious, but given that the particles contain
no genome, it is unclear how this occurs.
	Prusiner recently wrote a review on Prions (which cause scrapie,
Creutzfeld-Jacob Disease, one other human disease whose name escapes me,
and Bovine Spongiform Encephalitis) that appeared in one of the
Annual Review of something books (this year).

	Anyway, getting back to the Science News article (from this week,
I forgot to mention the source above),  somebody working on a normal
brain protein that activates a generally non-reversible membrane signal
finally isolated said protein.
	Comparison to Genbank pulled out the scrapie prion protein.

	The hope is that this really IS the scrapie protein in its 
normal state.  And if you can figure out what it normally does, you
can figure out why it is "infectious" in an altered state.

	Kind of a coincidence that you decided to bring it up.

	By the way, the prion form of the protein is heavily
glycosylated, as is the normal form, but the pattern is different. The
prion form is also more resistant to protease digestion. It's still
hard to say exactly what it going on here.  It no longer appears to
violate the central dogma of molecular biology which states that genetic
information goes through RNA (mainly but not always from DNA) to
protein and never vice versa, but it still appears fascinating
nonetheless, whatever it turns out being inthe end.
~.

-- 
	        Craig Werner   (future MD/PhD, 4.5 years down, 2.5 to go)
	     werner@aecom.YU.EDU -- Albert Einstein College of Medicine
              (1935-14E Eastchester Rd., Bronx NY 10461, 212-931-2517)
              "Politics is nothing more than medicine on a grand scale."