mmm@cup.portal.com (Mark Robert Thorson) (11/12/89)
A couple years ago, a researcher at UCSF claimed that certain diseases, including scrapie and Creuzfeldt-Jakob syndrome, were caused by an infective agent he called "prions". Prions are said to be like viruses, but are composed of protein only, no RNA or DNA. If true, this seems to me to be one of the most important discoveries of the decade. Yet, I've heard almost nothing on this topic since SCIENTIFIC AMERICAN published an article. What is the current status of prions? Has the theory been discredited or what?
BCHS1B@jane.uh.edu (11/13/89)
In article <23936@cup.portal.com>, mmm@cup.portal.com (Mark Robert Thorson) writes: > A couple years ago, a researcher at UCSF claimed that certain diseases, > including scrapie and Creuzfeldt-Jakob syndrome, were caused by an > infective agent he called "prions". Prions are said to be like viruses, > but are composed of protein only, no RNA or DNA. > > If true, this seems to me to be one of the most important discoveries > of the decade. Yet, I've heard almost nothing on this topic since > SCIENTIFIC AMERICAN published an article. What is the current status > of prions? Has the theory been discredited or what? Although I am not fully update on prions I've read some journal articles other than SciAm. The theory has not been discredited, to the contrary many people are interested in this problem. The most recent work I read identified the protein comprising the prion as actually being a normal cellular protein whose expression has somewhat gone haywire. The route of infectivity was not clear to me, but they are still working on it. MIke Benedik Biochemical Sciences University of Houston
dmark@acsu.Buffalo.EDU (David Mark) (11/13/89)
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? Just a comment on the name. The name "Prion" is unfortunate, since that is the common English name of a group of southern hemisphere pelagic birds, related to petrels. "Prions" are also know as "whale-birds", and apparently used to hang arong whales and eat the krill and other plankton that the whales injure or otherwise stir up. David Mark dmark@cs.buffalo.edu
werner@aecom.yu.edu (Craig Werner) (11/14/89)
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."