Figure 4.

Decreased apoptosis in Apaf1^yautja mutant embryos. (a) Apaf1^yautja MEFs are less susceptible to death by apoptotic stimulation than wild-type cells. Viability of WT or MUT MEFs following 4-h stimulation with staurosporine (2 μg/ml) or with TNF-α (25 ng/ml) and cycloheximide (CHX; 5 μg/ml; n=4). (b) Apaf1^yautja MEFs are unable to activate effector caspases. Levels of DEVDase-specific caspase activity relative to untreated WT MEFs determined 4 h after stimulation (n=3). Error bars indicate standard deviation (S.D.) of the mean. (c) Representative images of MEFs in culture 4 and 8 h after treatment with TNF and CHX. (d) LysoTracker Red staining shows decreased cell death, and (e) anti-phospho-histone H3 immunofluorescence shows increased proliferation in the maxillary prominences (MxP) of E9.5 Apaf1^yautja embryos. Horizontal sections at the level of the maxillary component of the first branchial arch. Dorsal is to the top. Scale bar=100 μm