Enhancement of transgene expression in mammalian cell line by a Δ⁷-prostaglandin A₁ analogue

We transfected a Chinese hamster ovary cell line, CHO-K1, with the gene of the Escherichia coli β-galactosidase (β-Gal) or the firefly luciferase (Luc) gene together with neo^R gene, and isolated the stable transfectants, designated as CHO-Z neo and CHO-Z neo, respectively. When these cells were incubated for 24 to 72 h with 1.0 μg/ml TEI-3313, a Δ⁷-prostaglandin A₁ analogue, the total and the specific activities of β-Gal and Luc were enhanced severalfold. It was confirmed by immunotitration experiments that the enhancement of β-Gal activity was due to an increase in the level of enzyme protein. Northern blot analysis revealed that this compound augmented the level of β-Gal mRNA. On the other hand, it did not significantly affect the expression of an endogenous gene such as that encoding lactate dehydrogenase or β-actin.