FIG. 1.

HEF1 expression causes cell death. (A) Cells were grown for 48 h in the presence (uninduced) or absence (induced) of tetracycline and, where indicated, TNF-α and were examined by phase-contrast microscopy. HEF1 stable transfectants (HEF1 cell line) were compared with a negative control cell line (vector cell line). (B) Cells were grown in the presence or absence of tetracycline, and cell numbers were determined over a 72-h period using the MTT cell viability assay. Circles indicate the HEF1 cell line and squares indicate the vector control cell line grown in the presence (solid) or absence (open) of tetracycline. Data points represent the average of six replicates from two independent experiments. Error bars indicate the standard errors of the mean.