(A) Wild type mice were administered a single BrdU injection to
label cycling cells. After a month, the tissue was analyzed.
(B-I) After one month, none of the remaining BrdU+ cells
expressed markers of stem cell (C, G) or secretory precursor (D-F). All
BrdU+ cells were positive for lysozyme (B) and surface
UEA (H). Scale bar, 10 μm.
(J) One month after tamoxifen injection of
Lyz1CreER/+; R26R-tdT mice, all
remaining tdT+ cells were positive only for Paneth cell
markers.
(K) Experimental scheme: one month after tamoxifen injection of
Lyz1CreER/+; R26R-tdT mice, animals
were irradiated then sacrificed 7 days after irradiation to determine whether
radiation induces mature Paneth cell to proliferate.
(L, N) Radiated Lyz1CreER/+;
R26R-tdT mice showed villus and crypt localized
tdT+ stripes.
(M) Villus tdT+ cells in irradiated animals
expressed enterocyte marker SI. Scale bar, 10 μm.
(O, P) Crypt tdT+ cells in irradiated animals
showed PCNA+ (O) and Ki67+ (P) cells.
Scale bar, 10 μm.