THE 3'-END OF THE HUMAN BETA-ACTIN GENE ENHANCES ACTIVITY OF THE BETA-ACTIN EXPRESSION VECTOR SYSTEM - CONSTRUCTION OF IMPROVED VECTORS

The human beta-actin promoter has been widely used to drive expression of genes of interest in mammalian cell lines and transgenic mice. The original form of the human beta-actin expression vector contains upst ream sequences, 5'UTR (untranslated region) and intron 1 from the beta -actin gene linked to a three restriction site polylinker and SV40 (Si mian Virus 40) 3'UTR. We have modified this vector now to contain the highly conserved beta-actin 3'UTR plus flanking region which replaces the SV40 sequences. An additional modification has removed the mRNA pe ripheral localization sequences present in the beta-actin 3'UTR. The n ew vectors also contain an improved polylinker. The activity of these two new vectors has been compared with that of the original vector and that of a vector using the popular cytomegalovirus (CMV) promoter. Mo use C2 myoblasts were transfected with each vector driving expression of enhanced green fluorescent protein (EGFP) and analyzed for EGFP mRN A levels. We find that both new vectors drive twice the level of mRNA accumulation of the original vector and over 30-times that of the CMV promoter. This suggests that these new vectors will provide a substant ial elevation in levels of expression by virtue of inclusion of the be ta-actin 3'UTR plus flanking region. (C) 1997 Elsevier Science B.V.