large (>60 kb) multicopy plasmid replicons

Ashok Aiyar aiyar at biocserver.BIOC.CWRU.Edu
Sat Nov 25 10:54:37 EST 1995

I am looking for a source (or references to) E. coli plasmid
replicons that support the stable replication of large plasmids
in the range of 5 - 20 copies per cell (or greater).

We are currently using an F episome that is around 70 kb to
carry a large portion of Epstein Barr Virus in it.  This 
replicates at about 1 copy per cell, which makes DNA isolation
for cloning and transfection purposes rather difficult.

I would like to replace the F episome origin with an alternative
origin that supports the stable replication of large plasmids
at higher copy number.  The only origin that I am aware of that
might work is the R6K origin.  Are there any others I should be
looking at?  The ColE1 origin has not worked for this purpose.


Ashok Aiyar
Marriage is the only adventure open to the cowardly.
- Voltaire

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