Figure 5

Synaptic acetylcholinesterase (AChE_S) polypeptides digest chromosomal DNA in pre-fixed HeLa cells. HeLa cells were pre-fixed with 4% paraformaldehyde and permeabilized with 0.5% Triton X-100 before incubation with hAChE_S polypeptides. (a) Confocal images showing deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL)-stained nuclei of HeLa cells. The pre-fixed and permeabilized HeLa cells were incubated with hAChE-T547 (0.2 μM) (left panel) or with hAChE-T107 (5 μM) (right panel) at 37 °C for 6 h. The TUNEL assay was then performed and the confocal images were taken. Bovine serum albumin (BSA) (0.2 μM) and T41 (5 μM) were used as negative controls, respectively. Scale bar, 20 μm. (b) Agarose gel images showing DNA fragmentation in pre-fixed HeLa cells incubated with hAChE-T547 (21 μM) at 37 °C overnight. BSA (21 μM) was used as a negative control. DAPI, 4',6-diamidino-2-phenylindole.