what is a retrovirus?

[Atley Jonas]

In article <4al90i$95p at ccshst05.cs.uoguelph.ca>, rthornhi at uoguelph.ca 
says...
>
>Please excuse my ignorance, but I would really like a clear definition 
>for the term, "retrovirus."   Any help would be much appreciated.
>
>Thank you in advance!
>
>rebecca thornhill


Ok,  without knowing how detailed of an answer you expected, here's what I 
can tell you:

Webster's defines a Retrovirus as: a type of RNA virus that invades the 
body's cells, where it produces more such RNA viruses: includes the AIDS 
virus and many cancer-causing viruses.

Now, I assume that you are looking for a bit more depth than that, so here 
is some information on the virus:

the family of viruses known as Retroviridae are the viruses which are well 
known to us as the viruses responsible for diseases such as AIDS, as well as 
various cancers, (TTLV, Leukemia.)

It is regarded as a level 3 pathogen, and its primary characteristic is that 
through the process of reverse transcriptase, (<-- which is an RNA-dependent 
DNA polymerase; an enzyme,)  synthesizes a copy of DNA from its own RNA, 
using it as a template.  The viral DNA will integrate into a host cell 
chromosome, where it becomes known as a "provirus,"  (not to be confused 
with prophage!)  Then, one of two things happens:  the viral DNA can remain 
latent, replicating with the host cell whenever the host cell replicates, or 
it can begin transcription, and produce many new viruses, infecting nearby 
cells. Finally, the virus can also convert the host cell into a tumor cell, 
causing unregulated cell division, (beginnings of cancer.)

Its characteristics include:  an envelope with envelope proteins surrounding 
the exterior, inside is an icosohedral capsid, with diploid (2 copies of) 
RNA in the centre.

As you may probably know, this is a real tough pupppy to deal with, and 
science hasen't yet come up with an effective cure, although there are 
several agents constantly being tested, (such as AZT,) but a large obstacle 
to finding effective treatment is extreme toxicity of the drugs themselves, 
which cause some nasty side-effects.  

Well, that's all that I can really come up with right now - I can't think of 
anything else.  I hope this is clear and consise enough.  If it is, I'm glad 
I could be of help.


Atley Jonas

(Uof A)
(Bio.Sci.III(Genetics))