TABLE 2.

Cell cycle distribution of synchronized HeLa cells treated with C. botulinum C2 toxin^a

Cells	% of cells (mean ± SD [n = 6])
	9.75 h after release			11.25 h after release
	G2	M	G1/S	G2	M	G1/S
Control	62 ± 8	19 ± 5	19 ± 6	7 ± 5	10 ± 4	83 ± 8
C2 treated	85 ± 4	9 ± 3	6 ± 3	54 ± 4	38 ± 5	8 ± 3

^aHeLa cells were synchronized with amethopterin and thymidine as described in the text, and at 4 h after release from the amethopterin block were treated with C2 toxin (200 ng of C2II and 100 ng of C2I per ml). At 9.75 and 11.25 h after release, toxin-treated and untreated control cells were collected from the dish by trypsin treatment and subsequent centrifugation. Part of the cells were fixed on glass slides, and their DNA was stained with the Feulgen reagent. Morphological analysis was carried out on enlarged photographic prints. The other part of the cells was analyzed by flow cytometry.