Figure 4
Diagram of cointegration and excision of replicons at alternative sites. The two megaplasmids of S. meliloti 1021 are represented in colors: red, pSymA; yellow, pSymB. The origins of replication are shown as OA for pSymA and OB for pSymB. Alternative sites for cointegration and excision are indicated: a, ISRm11; b, nodPQ genes. Oligonucleotides bordering the reiterated elements participating in cointegration and excision events are indicated by arrows and numbers. The structures resulting from alternative sites of cointegration of pSymA and pSymB as well as those resulting from alternative sites of excision of the pSymA-pSymB cointegrates are shown.
