An update of pTRIDENT multicistronic expression vectors: pTRIDENTs containing novel streptogramin-responsive promoters

We present an update on the pTRIDENT multicistronic mammalian expression ve ctors and their implications in various metabolic engineering and therapeut ic applications. The pTRIDENT vector family has been expanded by constructi on of a new set of pTRPDENT-based vectors containing constitutive promoters of human origin (ubiquitin C and EF-1 alpha promoters) and selectable mark ers (zeocin resistance) and expressing different reporter genes (secreted a lkaline phosphatase (SEAP) and the secreted single-chain urokinase-type pla sminogen activator (low-M-r u-PA)). In addition, we have constructed pTRIDE NT derivatives with novel streptogramin-repressible and streptogramin-induc ible promoters for simultaneous and adjustable expression of three differen t transgenes. Streptogramin-inducible and tetracycline-repressible pTRIDENT derivatives were used to simultaneously control expression of three fluore scent proteins in mammalian cells: the enhanced cyan fluorescent protein (C FP), the recently isolated red fluorescent protein (RFP, also designated ds Red), and the enhanced yellow fluorescent protein (YFP). Owing to their mod ular structure, the pTRIDENT vector family represents a construction kit fo r the design of novel multicistronic expression constructs.