Analyses of alternative poly(A) signals for use in baculovirus expression vectors

Synthetic, duplicated, or heterologous sequences encompassing putative 3' mRNA processing (polyadenylation, poly(A)) sites have been analyzed with regard to their involvement in processing mRNA species synthesized from the polyhedrin promoter of Autographa californica nuclear polyhedrosis virus (AcNPV). The data indicate that a synthetic sequence based on the 3' processing signal of the rabbit beta-globin gene is used more efficiently than an SV40-based, early gene poly(A) signal, or the AcNPV 1629 ORF poly(A) signal. Evidence is presented that indicates that the hexanucleotide AAUAAA alone is inadequate to effect mRNA processing. This supports the view that like other eukaryotic mRNAs additional signals are involved.