Mahjong acts as a downstream target of Lgl in cell competition and basal cell extrusion.

The mosaic analysis with a repressible cell marker (MARCM) system was used to overexpress UAS constructs in either mahj−/− clones (A) or lgl−/− clones (B, D, and E). Homozygous mutant clones are marked by the expression of GFP. (A) mahj−/− MARCM clones overexpressing Lgl at 96 h after clone induction. (B, D, and E) lgl−/− MARCM clones overexpressing Mahj at 144 h (B and D) or 96 h (E) after clone induction. (C) Quantification of apoptotic cells in the lgl−/− mosaic wing discs with or without overexpression of Mahj. The percentage of apoptosis occurring in lgl−/− cells on the boundary with wild-type cells was examined. The results represent means±SD (n = 13 discs, *p<0.001). (D) A transverse section. Anti-cleaved Caspase-3 (A and B), anti-DE-Cadherin (D), and anti-phospho JNK (E) antibodies were used for immunostaining. (A, B, D, and E) Nuclei were stained with DAPI (blue).