title: The plasmid cloning vector pBR325 contains a 482 base-pair-long inverted duplication.
abstract: The plasmid pBR325 is a cloning vector constructed in vitro by addition of the chloramphenicol resistance (Cmr) gene of an IS1-flanked transposon to pBR322 (Bolivar, 1978). It is a 5 995 bp plasmid carrying no sequence originating from IS1. DNA-sequence data suggest that its Cmr segment was derived from a Cm transposon longer than Tn9. The plasmid pBR325 carries between the Cmr and Tcr genes a 482 bp sequence which duplicates, in the opposite orientation, a section pf pBR322 located at the end of the tcr gene. The same structure was found in pBR328, a deletion derivative of pBR325 (Soberon et al., 1980). The possible implications of this inverted duplication on cloning experiments are discussed.
mesh_terms: D001483:Base Sequence; D007446:Chromosome Inversion; D003001:Cloning, Molecular; D004261:DNA Replication; D004269:DNA, Bacterial / Q000032:analysis; D004926:Escherichia coli / Q000235:genetics; D005822:Genetic Vectors; D010641:Phenotype; D010957:Plasmids
chemical_list: D004269:DNA, Bacterial