Fig 4. Scrib, Dlg, and Lgl localise to SJs but are not required for SJ formation or apical–basal polarity.

(A) Mosaic knock-down of Scrib by RNAi in adult ECs. The SJ markers Cora (green) and Mesh (red) localise normally in cells depleted of Scrib (white). The ECs lacking Scrib are indicated by dashed lines above. (B) Dlg (red) does not localise to the SJs in Scrib–RNAi MARCM clones (marked by GFP, green). (C) Cora (red) and Scrib (white) localise to the SJs in dlg1¹⁴ MARCM clones (marked by GFP, green). (D) Lgl does not localise to the SJ between dlg1¹⁴ mutant cells (marked by GFP, green). The white arrow indicates the SJ between the dlg1¹⁴ mutant cells. (E) Myo7a (red) and Scrib (white) localise normally to the apical cortex and SJs respectively in lgl⁴ MARCM clones (marked by GFP, green). (F) Dlg (red) and pMoe (white) localise normally in lgl⁴ mutant cells (marked by GFP, green). White asterisks mark the mutant cells. Scale bars, 10 μm. Dlg, Discs large; EC, enterocyte; GFP, green fluorescent protein; Lgl, Lethal (2) giant larvae; MARCM, mosaic analysis with a repressible cell marker; Myo7a, Myosin 7a; pMoe, phospho-Moesin; RNAi, RNA intereference; Scrib, Scribbled; SJ, septate junction; UAS, Upstream Activation Sequence.