In article <Pine.SOL.3.91.960229145323.11886A-100000 at tam2000.tamu.edu>,
Wade <dwl0685 at tam2000.tamu.edu> wrote:
>>I have been doing some paper research lately on picorna(esp. polio)
>viruses and have found that an explanation for the extensive CPE
>generated by multiplying polioviruses has yet to be explained. Many
>suggestions exist, but I would like to see what others have to say as far
>as information or opinions on how the host cell is destroyed so rapidly.
I believe that CPE, in general, is a poorly understood process, and that
in few cases is it really clear exactly why viruses kill cells. That is,
although there are some mechanisms which will clearly kill a cell (e.g.
those viruses which burst the cell to exit), it's rarely clear whether
the cell is even alive at that point, and whether that mechanism, or
another or some combination of many, is responsible. It seems even more
difficult to point to causes for some of the pre-death changes in the
cells that are often seen - the rounding and clumping, vacuolation, etc -
although in some cases it seems that disruptions in cytoskeletal networks
and so forth are involved (though that's merely refining the description
and doesn't really address a mechanism).
I'm far from an expert on this, and I'm sure that there are some cases
where there are clearly understood mechanisms. I suspect, though, that
these are the minority.
In the case of polio, one factor that seems likely to muck up an infected
cell in a real hurry is the recently described inhibition of glycoprotein
trasport in infected cells (Doedens, J.R. and K. Kirkegaard. 1995.
Inhibition of cellular protein secretion by poliovirus proteins 2B and 3A.
EMBO J.14:894-907; Barco, A. and L. Carrasco. 1995. A human virus
protein, poliovirus protein 2BC, induces membrane proliferation and blocks
the exocytic pathway in the yeast Saccharomyces cervisiae. EMBO
J.14:3349-3364).
Ian
--
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
