Figure 5. Expansion of the NEB-associated Club cells (CC) in the absence Delta ligands.

(A) Double immunofluorescence of E18.5 control and Dll1^cnull; Dll4^cnull lungs: Ascl1 and Cgrp expression in control and in the abnormally expanded NEBs (dotted areas) of mutants; robust N1ICD and SSEA1 expression in NEB-associated CCs (arrowheads and brackets). (B) Double ISH (Cyp2f2)/immunohistochemistry (Ascl1) showing strong Cyp2f2 expression (arrowheads) in cells flanking the NE microenvironment but only low signals in the NEB-associated CCs (asterisks) of both control and Dll1^cnull; Dll4^cnull mutants. Note reciprocal high (arrowhead) and low (*) intensity of signals in areas inside and outside the NEB microenvironment. Scale bars in A = 20 μm.