L3S2P21 strong synthetic terminator

The L3S2P21 terminator is a strong synthetic terminator. This terminator was selected from a library of synthetic Escherichia coli intrinsic (? factor?independent) terminators. Intrinsic terminators consist of a simple motif in the nascent transcript: a short RNA hairpin followed by a U-rich sequence (U-tract), both of which are required for efficient termination. The terminator library was built up by combining different hairpins and U-tracts with the intent of determining the effects of each parameter on terminator strength. Terminator strength was determined from a simple assay that compares the expression of two fluorescent reporters, one placed before and one after the terminator (Chen et al. 2013).