A human beta-actin expression vector system directs high-level accumulation of antisense transcripts.

Abstract
We have constructed a mammalian expression vector consisting of 3 kilobases of the human .beta.-actin gene 5'' flanking sequence plus 5'' untranslated region and intervening sequence 1 linked at the 3'' splice site to a short DNA polylinker sequence containing unique Sal I, HindIII, and BamHI restriction endonuclease sites followed by a simian virus 40 (SV40) polyadenylylation signal. Two derivatives containing the selection markers obtained from pSVgpt or pSV2neo, were also generated. We find that the promoter activity of this vector is as great or greater than that of the SV40 early promoter in a variety of human and rodent cells. The vector was used to generate .gamma.-actin and .beta.-tubulin antisense transcripts in human fibroblast cell lines. The antisense transcripts accumulate to levels comparable with that of the highly abundant .gamma.-actin and .beta.-tubulin mRNAs.