Wg pathway activity gradients around adult intestinal compartment boundaries.

(A) Expression pattern of fz3-RFP and nkd-lacZ, two Wg activity reporters, in the adult gut. Anterior to the left. The two blue arrows indicate constriction sites around R3. Scale bar: 100μm. (B-D’) Higher magnification view of (A) around cardia (B and B’), CCR (C and C’) and R5-HPZ region (D and D’). Scale bar: 50μm. Note: the expression of nkd-lacZ around R2-R3 boundary is variable between guts. (E) Merged expression pattern of fz3-RFP and nkd-lacZ from the middle of R4 to the R5-HPZ boundary. Anterior to the left. Scale bar: 100μm. (F) Quantification of fluorescent intensity in (E) from R4 to the R5-HPZ boundary shows gradient expression of both reporters, high at the boundary and low inside compartment. (G-J’) Low-level Wg pathway activities are present inside midgut compartments. Scale bar: 10μm. (G-H’) Wild-type MARCM clones do not affect fz3-RFP or nkd-lacZ expression inside R4. (I and I’) MARCM clones of pygo deplete fz3-RFP signal inside R4. (J and J’) MARCM clones of dsh diminish nkd-lacZ signal inside R4. (K) Schematic view of wg expression and Wg pathway activation in the adult intestine.