Fig. 3.

Apoptosis and S-phase proliferation in WT and PolgD257A crypts of Lieberkühn. Apoptosis is located in the region of the transit amplifying cells of WT (A) and PolgD257A (B) crypts. WT crypts have few apoptotic cells while PolgD257A mice have numerous apoptotic cells. Quantification of apoptotic cells per crypt (C) comparing WT and PolgD257A mice. 5-Ethynyl-2′-deoxyuridine (EdU) incorporation into cells in the transit-amplifying region is found at 2 h after EdU administration in the crypts of WT (D) and PolgD257A (E) mice. WT mice have numerous and robust staining of S-phase cells in this region while PolgD257A mice have fewer and less intense staining of S-phase cells in this region. Quantification of total cells per crypt (F), EdU-labeled cells per crypt (G), and fraction of EdU-labeled cells of total cells (H) comparing WT and PolgD257A mice. Approximately 50 crypts were scored spanning the entire small intestines from each of 4 WT mice and 4 PolgD257A mice. Average number of cells/crypt section were obtained for each mouse and represented as means ± SE from the 4 animals in each group. Number of mice is indicated within the bars. Nuclei staining (DAPI), blue; apoptosis (TUNEL), green; and EdU cells, yellow. ***P < 0.001.