Smallest Plasmid Origin - 393bps?

[John Dixon]

Hi all, I am after as small an origin as possible (for a plasmid rescue
system). ColE1 seems to be 900 or so bps, we have some old vectors with
pBR oris of 580bps, and I've just found a ref (Thomas et al Mol Gen Genet
1981 1-16 that talks of oriRK2 a 393bp fragment but this requires trans
acting factors to be present in the genome of the bacteria or on another
compatible plasmid.

Is this the smallest ori? Can anyone point me in the right direction for
some newer refs?

Cheers

Johnny D

-- 
John Dixon                                        Lab 44 (1223) 334131
Wellcome/CRC Institute                            Fax 44 (1223) 334134
Department of Genetics
Cambridge University    
United Kingdom                           e-m: jpcd0 at mole.bio.cam.ac.uk