Figure 2.

Integrative base vector pBBintФ structure. It is a chloramphenicol-resistant vector with a conditional replication origin (R6K) that impairs its replication in commonly used E. coli strains (without pir or pir-116 gene). Two FRT sites flank the resistance gene and the conditional origin, so that they can be excised via Flp-mediated recombination once integrated in the genome, thus leaving a marker-less integrant without R6K. This vector targets the Ф80 attB site in the chromosome of E. coli via the attP integration guide in the vector. The attP sequence is flanked by two NheI restriction sites to enable the engineering of this base vector by easily changing the guide. The cloning site is flanked by BioBrick™ Prefix and Suffix sequences, while four transcriptional terminators implement the insulation of the part when placed in the genome. Primer binding sites are also present. The default insert of the vector is an mRFP1 constitutive expression cassette, driven by the PR promoter. The glossary explains all the used symbols and lists the BioBrick™ basic parts used to compose this vector.