FIG. 4.

In-frame deletion of hisZ gene in the histidine operon. The designed structure of the hisZ in-frame deletion. The ORFs are represented by open arrows, the promoter region is represented by a bent arrow, and the transcription terminator is represented by a lollipop. Cre-mediated excision of the lox-flanked zeocin-resistant marker is predicted to create a translatable scar sequence that is in frame with the hisZ gene (N-terminal 9-nt coding region and C-terminal 30-nt coding region). Translation from the ΔhisZ Shine-Dalgarno sequence and start codon is expected to produce a 43-residue peptide with the HisZ N-terminal MetPheMet, 31 scar-specific residues, and 9 residues of the HisZ C terminus. The scar sequence is shaded, and the lox72 site is boxed.