Fig. 3.

Caspase activity in cytosolic extracts of sciatic nerve and thymocytes. Extracts were prepared from P0 thymocytes treated with STS and CHX (Thy + STS) or from P7 sciatic nerves that were cultured as explants for various times or that were treated with STS and CHX for 4 hr (4 h + STS) or 10 hr (10 h + STS). The extracts were assayed for their ability to cleave the fluorogenic caspase substrate zDEVD-AFC. There is little caspase activity in extracts from nerves undergoing Wallerian degeneration. Data from a representative experiment are shown. The experiment was repeated three times with similar results, and similar results were obtained when zVEID-AFC or zYVAD-AFC was used as a substrate.