Illustration of plasmids carrying intact or truncated tetA genes. Plasmids are not drawn to scale. (A) Plasmid pACYC184 carries an intact tetA gene (1191 bp), which is the source of all truncated tetA genes used in this study. Plasmid pYA4463 carries two copies of truncated tetA genes, truncated at the 5' or 3' ends as indicated, which results in a 466-bp direct tandem duplication (shown as open arrows). Plasmid pYA4590 has two similar copies of truncated tetA genes, resulting in 602 bp of repetitive sequence (shown as open arrows) separated by 1041-bp kan cassette. (B) Plasmid pYA4464 has a 3'tet truncated gene. Plasmid pYA4465 has a 5'tet truncated gene. There are 751 bp of common sequences (shown as open arrows) between the two truncated tetA genes. (C) Plasmid pYA4463 dimer is the intermolecular recombination product of two pYA4463 molecules. Plasmid pYA4590 dimer is the intermolecular recombination product of two pYA4590 molecules. Plasmid pYA4464-pYA4465 is the intermolecular recombination product of pYA4464 and pYA4465.
Zhang et al. BMC Microbiology 2011 11:31 doi:10.1186/1471-2180-11-31