title: An in vivo cointegrate of two plasmids from incompatibility group X.
abstract: Formation of a recombinant plasmid designated pNH603 was observed when two plasmids from incompatibility group X, the multicopy plasmid pNH602 (a higher-copy-number deletion derivative of R6K) and the oligocopy plasmid R485, coexisted in a single Escherichia coli cell. According to its size and its restriction endonuclease cleavage pattern, plasmid pNH603 is a true cointegrate of pNH602 and R485. An insertion-sequence-like element coming from plasmid R485 is supposed to mediate the fusion of both replicons. The pNH603 copy number (1-2 per chromosome) indicates that the mechanism of replication of the low-copy-number plasmid is dominant in this cointegrate. No dissociation of pNH603 to parental plasmids was observed even in E. coli K-12 recA+ cells. On the other hand, deletion derivatives of four size classes originate from pNH603 in both recA+ and recA hosts. A miniplasmid designated pNH604, a representative of the most frequent 7 Mg/mol size class, was found, in a low number of copies per host chromosome.
mesh_terms: D004261:DNA Replication; D004262:DNA Restriction Enzymes; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000032:analysis* / Q000302:isolation & purification / Q000648:ultrastructure; D015245:Deoxyribonuclease BamHI; D015246:Deoxyribonuclease EcoRI; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics*; D008854:Microscopy, Electron; D010957:Plasmids; D011995:Recombination, Genetic
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes; D015245:Deoxyribonuclease BamHI; D015246:Deoxyribonuclease EcoRI