Schematic representation of Nuc cassettes for controlled and targeted production in L. lactis.For details about plasmid constructions and contents see Bermúdez-Humarán et al. (2003) . Plasmid backbone is a derivative of the rolling circle plasmid pWVO1, an E. coli-Gram positive shuttle vector. Arrows (1) indicate the presence of the nisin-inducible promoter (P
); solid vertical bars (2) indicate the Ribosome Binding Site of the usp45 gene; the striped bar indicate signal peptide of the usp45 gene (SPUsp); the white bar indicates the insertion of LEISSTCDA synthetic propeptide ; dark gray bars indicates Nuc mature coding sequence; stem-loop structures indicate trpA transcription terminators (not to scale). A NsiI restriction site comprises the ATG start codon (in pCYT) or the last two residues of SPUsp (pSEC) and allows a simple and one-step cloning of the cassettes corresponding to the mature proteins for cytoplasmic production (pCYT) or secretion (pSEC).