Relationship of the Replication and Incompatibility Genes of an IncFVI Haemolysin Plasmid with Other F-like Haemolysin Plasmids

Abstract

The replication and incompatibility region of the IncFVI plasmid pSU502 has been isolated by in vitro DNA manipulation as part of a 12.6 kb plasmid, denominated pSU503. Plasmid pSU503 was strongly incompatible with its parental plasmid, pSU1, but was fully compatible with the haemolytic plasmids pSU3 16 (IncFIII/IV), pHly152 (IncI2) and pSU233 (Inc-pSU233). Furthermore, the 6.9 kb EcoRI fragment of pSU503 which carries the replication and incompatibility determinants of pSUl did not show any detectable homology (< 70%) with any of the haemolysin-determining plasmids with which it is compatible. Thus, homologous haemolysin determinants have become linked to apparently unrelated replicons.

Isolation and evolutionary analysis of a RepFVIB replicon of the plasmid pSU212

“…The results, shown in Table 1, indicated that (i) the 0.8 kb fragment contains an incompatibility determinant; (ii) this incompatibility determinant is able to suppress the replication of the miniplasmid pSU325 1, which strongly suggests that pSU325 1 is replicated from the RepFVIB replicon; and (iii) the fragment does not inhibit the replication of the parental plasmid pSU401. This last result was consistent with that of Zabala et al (1983) and indicated the presence of more than one functional replicon in pSU401. In addition, pSU3252 showed partial incompatibility towards the IncFVII miniplasmid pSU3201.…”