Similar effects of electroporational stress and treatment with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate on vimentin expression in mouse plasmacytoma cells.

ABSTRACT

In mouse plasmacytoma cells (MPC-11), an activation of the normally repressed vimentin gene was observed as a response to transfectional stress. Effects of electroporation on vimentin gene expression were compared at the cellular and chromatin level to those caused by treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA). At the cellular level, similar changes in vimentin gene activity and cell-cycle distribution were observed by flow cytometry, whereas at the chromatin level similar changes in patterns of hypersensitive regions were detected by DNase I mapping. Additionally, a region located 700 bp upstream of the transcriptional start became hypersensitive to DNase I digestion upon electroporation and TPA treatment. This region overlaps two adjacent AP-1-like binding elements and generates specific DNA/AP-1 complexes in bandshift experiments. Therefore, the transcription factor AP-1 seems to play a central role in the activation of vimentin gene expression induced by these 2 different forms of stress.