Fig. 1. Morphological and cell cycle analyses of synchronized G₁ and TGF-ß1-induced apoptotic HuH-7 cells. The cells were treated with 1 nM TGF-ß1 for 72 hours (left panels) or synchronized at G₁ (right panels) as described in Materials and Methods. (A) Fluorescent labeling of nuclei with Hoechst 33258 showing the characteristic nuclear fragmentation associated with TGF-ß1-induced apoptosis (left). (B) Analysis of cell cycle phase by flow cytometry after removing apoptotic cells. The percentage of total cells present in the different cell cycle phases is indicated in the top-right panel.