Giovanni Maga maga at
Thu Feb 2 04:25:14 EST 1995

In article <1995Jan30.083126.23334 at>, jpcadore at
(Jean-Paul cadoret) wrote:

> Hi netters
> The sv40 doesn't repilcates only in monkey, right ?
> have the factors responsible for this specificity identified ?
>  have they been cloned. Is the primase the only one ?
> thank you in advance
> jpc

The protein which is necessary and sufficient for both initiation of
replication and transforming ability of SV40 is the large T Antigen (TAg).
There is also a small TAg, but it seems only to help (its functions overlap
with the ones of large TAg). TAg has many functions: its role in
replication is due to two activities: origin binding protein (which opens
DNA at the ori) and helicase. TAg binds RP-A and pol alfa/primase of the
host which initiates replication. Then all the host replication machinery
makes the job (pol delta and/or pol epsilon, RF-C, PCNA, MF-1, RNase H
etc.). The SV40 replication system in vitro has been used as a model system
to study replcation in mammals. It requires human enzymes (thus indicating
that the ability of SV40 to replicate in humans is due to TAg). For an
exstensive review of the cellular factors required in vitro for replication
with SV40 DNA and TAg see recent papers by Waga and Stillmann appeared in
Nature (369, 19 May 1994, pp207-212) and JBC (269, 14, pp10923-10934,
1994). Hope it will be of interest for you.
G. Maga
maga at  

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