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Fig. 3. Msi-1 expression correlates spatio-temporally with adult progenitor cells
during intestinal remodeling. Cross-sections were immunostained with Msi-1
(A,C,F,H), PCNA (E,I) and IFABP (J) antibodies and stained with methyl
green-pyronin Y (B,D,G). (A) Stage 57. The larval epithelium (LE) is negative
for Msi-1. (B,C) Stage 60. Progenitor cells of the adult epithelium between
the larval epithelium and the connective tissue (CT) are weakly positive for
Msi-1 (arrowheads). (D-F) Stage 61. The adult epithelium (AE), where
PCNA-positive cells are localized, is positive for Msi-1. The degenerating
larval epithelium remains negative. (G-J) Stage 63. The adult epithelium
completely replaces the larval one. Msi-1-immunoreactivity is weakly
detectable only in the trough of newly formed folds (Fo), where PCNA-positive
cells are localized (I; arrows). IFABP immunoreactivity increases in intensity
from the crest to the trough of the folds. Bars, 20 µm.