Nucleic Acids Research, 1988, Vol. 16, No. 21 10171-10181
© 1988
MOLECULAR BIOLOGY |
A novel enhancement of SV40 enhancer activity by treatment of mouse neuroblastoma N18TG2 with protein kinase inhibitor H-7
Faculty of Pharmaceutical Sciences, Okayama University Tsushima-naka, Okayama 700, Japan
*To whom correspondence should be addressed
Received July 20, 1988. Accepted October 7, 1988.
To determine the role of protein phosphorylation in transcription regulation, we have treated mouse neuroblastoma N18TG2 cells with the protein kinase inhibitor H-7 and tested its effect on transcription. After the preculture and transfection in the presence of H-7, the cell preparation was divided in half and cultured with and without H-7. The level of CAT expression of pSV2-CAT was found to be higher in the cells cultured in the absence of H-7 than in those cultured in the presence of H-7. This difference was observed only after pretreatment of the cells with H-7. suggesting that withdrawal of H-7 from the culture medium after preculture with H-7 gave an enhancing effect on CAT expression. This phenomenon was also observed with transformants that expressed the CAT gene of pSV2-CAT stably . The 72 base-pair (bp) repeat of SV40 DNA was responsible for this difference in CAT expression. A similar effect of H-7 on the SV40 enhancer activity was observed in mouse neuroblastoma x rat glioma hybrid NG108-15 cells, but not in rat glioma C6-BU-1 cells.