Plasmid incompatibility: cloning analysis of an inc FII determinant of R6-5

Abstract

SalI and PstI restriction endonuclease-generated DNA fragments that specify an FII-type incompatibility function (incFII) of the low copy number antibiotic resistance plasmid R6-5 have been cloned in the high copy number pBR322 plasmid vector. A 1-kilobase DNA sequence that contains this incFII determinant has been identified and is shown to have coordinates of 95.5 and 96.5 kilobases on the R6-5 plasmid physical map. Expression of incompatibility by the cloned PstI fragment depends on its orientation within the vector molecule. The behaviour of pBR322-incFII hybrid plasmids suggests that plasmid replication control is not the only mechanism that can cause incompatibility between two plasmids.

On plasmid incompatibility

“…In this case, the interference would be due to titration of the trans-active initiator. Thus the cloned ori of any of the iteron-bearing plasmids expresses incompatibility (2,77,98), as does that of the pT181 plasmids (59), whereas those of the directly regulated ColEl and IncFII plasmids do not (22,89). This incompatibility has been demonstrated as a destabilization of the parental plasmid by cloned fragments containing the origin.…”

Nucleotide sequence analysis of RepFIC, a basic replicon present in IncFI plasmids P307 and F, and its relation to the RepA replicon of IncFII plasmids

“…inhibits replication and determines the incompatibility behavior of these plasmids (16,39,44). This RNA, which is identical among R100, Rl, and R6, is transcribed within the leader transcript of repAl, but in the opposite direction.…”

An inhibitor of SOS induction, specified by a plasmid locus in Escherichia coli.

“…From plasmid R6-5 (17), DNA fragments bearing the psi' locus were cloned into plasmids pACYC184 (18), pBR322 (19), and pKT043 (20) to give plasmids pKT217, pKT200, and pKT246 (Fig. 4), which prevented X induction and restored the viability of GC908 [recA441 (A)] on EMMA medium at 420C.…”