Fig. 4
Intestinal epithelium-specific deletion of PRMT1 increases cell proliferation in the crypt. A High levels of PRMT1 are present in the crypt base and transit amplifying cells in wild type small intestine. 8-week-old adult wild type (PRMT1fl/flVil-Cre−/−) or PRMT1 knockout (PRMT1fl/flVil-Cre+/−) mice were injected with EdU to label proliferating cells. The proximal small intestine was then isolated for detection of EdU and PRMT1 expression by immunohistochemistry. The DNA was stained with Hoechst. Note that EdU labeled mostly transit amplifying cells which had high levels of PRMT1 in the wild type animals. There were also PRMT1-expressing cells at the bottom of the crypt where stem cells reside. Expectedly, no PRMT1 proteins were found in the epithelium of PRMT1 knockout mice (PRMT1fl/flVil-Cre+/−). Note the increased cell proliferation in the crypts of PRMT1 knockout mice. B, C PRMT1 knockout increases cell proliferation in both proximal and distal small intestine. Both proximal and distal small intestine of wild type and PRMT1 knockout mice were analyzed by EdU labeling and Hoechst staining (B) and the number of proliferating transit amplifying cells were quantified from multiple sections per animal (C). For both PRMT1 knockout and control wild type littermates, n = 4. ***p < 0.001