Coat protein mediated protection

RYBICKI, ED ED at micro.uct.ac.za
Mon May 2 06:17:44 EST 1994


Nice to see some discussion here...!  Hi, Ulrich!

> Third, here is MHO:
> The Greene and Allison paper is only significant when read in the 
context of 
> the prevailing paradigms in plant RNA virus 
recombination.
....
> I think the Greene and Allison paper did a good job of shooting down 
this straw 
> man argument.  Therein lies its significance.

I think anyone who has an interest in both plant and animal RNA 
viruses will have known that recombination can and does occur - and 
this was shown some years ago now, surely long enough ago that people 
really shouldn't have made the assumption that it was rare or did not 
occur?

> Now the view adopted by Falk and Bruening is:  even though 
recombination 
> between a transgene RNA and an inoculated RNA can occur under 
selective 
> conditions, RECOMBINANTS WILL NOT SURVIVE UNDER NON-SELECTIVE 
CONDITIONS.  

I still think my comment on the original Allison etc. paper is valid - 
WHERE IS THE REST OF THE EXPERIMENT?  Where is the test of a construct 
lacking the 3' non-coding viral RNA sequences?  Any recombination 
occurring between plant viral RNAs in the normal environment will in 
all probability (ie in most cases) involve template swaps during 
replication; this generally presupposes a replication origin on the 
RNAs that are being used as templates and/or some sequence homolgy 
between them.  Non-homologous recombination must always be a rarer 
event.

> I suggest that survival of non-
> selected recombinants of RNA viruses will soon be demonstrated.  

I think it already has...Adrian Gibbs and others pointed out long ago 
that at least one tobamovirus has a tymovirus-like 3'end; Allison (in 
Ahlquist's lab) has previously shown that CCMV looks like a 
recombinant.  Probably a not-particulalry-common means of generation 
of viral diversity over geological time.

> More combinations need to be tried under a variety of conditions.  
More 
> research should be done.

Heartily seconded.

  ____________________________________________________________________
 | Ed Rybicki, PhD             |         Well, I tip my hat           |
 | (ed at micro.uct.ac.za)        |      To the new constitution         |
 | Dept Microbiology           | Take a bow for the new revolution... |
 | University of Cape Town     |  Then I get on my knees and pray     |
 |                             |   We don't get get fooled again...   |
 | Private Bag, Rondebosch     |                                      |
 | 7700, South Africa          |         - Pete Townshend             |
 | fax: xx27-21-650 4023       |      (Won't get fooled again)        |
 ---------------------------------------------------------------------



More information about the Virology mailing list