pTRIPLEscript: a novel cloning vector for generating in vitro transcripts from tandem promoters for SP6, T7 and T3...

We have constructed a family of novel in vitro transcription vectors in which functional T3, T7 and SP6 RNA polymerase promoters are arranged in tandem and directed towards a multiple cloning site. This prototype vector, named pTRIPLEscript, permits the transcription of one strand of a DNA insert by any of the three commonly used bacteriophage RNA polymerases with no apparent cross talk, i.e., use of the wrong promoter sequence. The vector has two main uses: (i) to clone probe sequences that will be distributed to many laboratories, allowing the use of the most convenient RNA polymerase; and (ii) to circumvent the problem of RNA polymerase-dependent premature termination.