FIGURE 7.

Forms of tTG that assume an open conformation are consistently cytotoxic. A, cell lysates collected from NIH3T3 cells ectopically expressing the vector alone or the indicated forms of Myc-tagged tTG were immunoblotted (IB) with Myc and actin antibodies. B, NIH3T3 fibroblasts ectopically expressing the same Myc-tagged tTG proteins shown in A were cultured in medium containing 10% CS for ∼36 h and fixed. Immunofluorescence was performed on the cells using a Myc antibody to detect the transfectants. The cells were also stained with DAPI to label nuclei. Apoptotic cells were identified by nuclear condensation/blebbing. The experiment was performed three separate times, and the percent apoptosis for each condition was determined by calculating the ratio of apoptotic to non-apoptotic cells. The data shown represent the mean ± S.E.