prions

Ian A. York iayork at panix.com
Thu Apr 11 10:05:37 EST 1996


In article <Pine.SOL.3.91.960411081355.25245C-100000 at ursa.cus.cam.ac.uk>,
Tim Fitzmaurice  <tjf11 at cus.cam.ac.uk> wrote:
>On 10 Apr 1996, Ian A. York wrote:
>> I've assumed that the spread to the brain is within cells of the 
>> reticuloenbdothelial system - via monocytes/macrophages.  I suppose it 
>Would travel in this kind of cell not make it far more transmissible than 
>this kind of agent appears to be?

Joao Vasconcelos Costa has posted a reference that suggest that neuronal 
spread is at least one way of transport, though I haven't actually read 
that paper yet; so this answer is hypothetical.  I'd say, though, that 
(1) the agent can be pretty transmissible in the right situation, from 
what I can gather, and (2) even if it's not, the sticking point for 
transmissibility is not easy to point to from theory. 
>
>Has anyon seen any mention in any paper of a putative normal function of PrP
>gene products at all?

.... let's see ... I recall that when I was looking at sequences there 
was function proposed for the chicken version ... okay, here's what the 
swissprot database has to say (with a few deletions to save space):

Database: SWISS-PROT Protein Sequence Database (33.0, 2/96)
Query:  prion AND chicken

>> Document 1 <<
[PRIO_CHICK]    MAJOR PRION PROTEIN HOMOLOG PRECURSOR (PR-LP)
(ACETYLCHOLINE    RECEPTOR-INDUCING ACTIVITY) (ARIA) (65-21 PROTEIN).

SOURCE [SRC]
     GALLUS GALLUS (CHICKEN).

REFERENCE [REF]
     [1]
     SEQUENCE FROM N.A.
     MEDLINE; 93028411.
     GABRIEL J.M., OESCH B., KRETZSCHMAR H., SCOTT M., PRUSINER S.B.;
     PROC. NATL. ACAD. SCI. U.S.A. 89:9097-9101(1992).
     [2]
     SEQUENCE FROM N.A., AND SEQUENCE OF 25-51.
     TISSUE=BRAIN;
     MEDLINE; 91352049.
     HARRIS D.A., FALLS D.L., JOHNSON F.A., FISCHBACH G.D.;
     PROC. NATL. ACAD. SCI. U.S.A. 88:7664-7668(1991).
     [3]
     REVIEW.
     MEDLINE; 92111159.
     FALLS D.L., HARRIS D.A., JOHNSON F.A., MORGAN M.M., CORFAS G.,
     FISCHBACH G.D.;
     COLD SPRING HARB. SYMP. QUANT. BIOL. 55:397-406(1990).

COMMENT [COM]
     -!- FUNCTION: STIMULATE THE SYNTHESIS OF ACETYLCHOLINE RECEPTORS IN
         CULTURED CHICKEN MYOTUBES. MAY SERVE NORMALLY TO REGULATE THE
         CHEMORECEPTOR NUMBER AT THE NEUROMUSCULAR JUNCTION AND PERHAPS
         IN THE CENTRAL NERVOUS SYSTEM AS WELL.


There doesn't seem to be much evidence, though, that this is a real 
function - i.e. I haven't seen much followup to this. 
-- 
      Ian York   (iayork at panix.com)  <http://www.panix.com/~iayork/>
      "-but as he was a York, I am rather inclined to suppose him a
       very respectable Man." -Jane Austen, The History of England



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