Vectors for in vitro synthesis of poly(A)+RNA transcripts.

An RNA expression plasmid containing a maize zein storage protein gene was modified by the addition of an oligodeoxynucleotide duplex containing oligo(A30) in the RNA sense strand to the 3' flank of the gene. By linearizing the plasmid at either side of the oligo(A) region, transcripts with or without a poly(A) tail may be synthesized. Poly(A) addition dramatically increases the translation of SP6-transcribed zein transcripts in Xenopus laevis oocytes. We describe a derivative of pSP64, pSP64A, containing the oligo(A) region, which may be useful for the transcription of polyadenylated RNAs from any template DNA.