Fig. S1 Proliferation and differentiation of clones of stat- cells.
Confocal images of eye imaginal discs containing clones of cells of the indicated
genotypes. (A) Wild-type clones in the eye disc exhibited a normal proliferation
pattern, reflected by BrdU incorporation, shown in blue.
(B) Wild-type clones
exhibited normal photoreceptor differentiation pattern, reflected by ELAV expression
(blue). (C) A disc with wild-type clones, showing expression of Yki activity reporter
ex-lacZ (blue). (D) stat- cells (RFP+, GFP-) show no ectopic BrdU incorporation
(blue). (E) stat- cells (RFP+, GFP-) show a normal photoreceptor differentiation
pattern and ELAV expression (blue).
Fig. S2 stat- mutant cells do not show elevated levels of apoptosis.
Confocal images of eye imaginal discs containing clones of cells stained with
antibodies to detect activated caspase (blue in A-D, grey in A’-D’) indicating cells
undergoing apoptosis. A GFP-marked chromosome of the indicated genotype was
flipped against an RFP-marked chromosome of the indicated genotype. (A) A control
GFP-bearing chromosome was flipped against an RFP-bearing wild-type chromosome.
(B) A stat- chromosome with an RFP marker was flipped against a GFP-bearing
chromosome. (C) A GFP-bearing scrib- chromosome was flipped against an RFPbearing chromosome. The scrib- clones have elevated levels of cells that are positive
for activated caspase. (D) A GFP-bearing scrib- chromosome was flipped against an
RFP-bearing stat- chromosome. scrib- cells but not stat- cells show elevated levels of
activated caspase. (G) Quantification of the number of dying cells of each class
expressed as the fraction of dying cells for that class. Wild-type (+) and stat- cell
populations showed low numbers of apoptotic cells, independent of the genotype of
the neighboring cells. scrib- clones showed high levels of apoptotic cells.
1
Fig. S3 Multiple stat- mutations result in a loss of competitive fitness against
scrib- cells.
Confocal images of eye imaginal discs containing clones of cells of the indicated
genotypes. A GFP-marked chromosome was flipped against an unmarked
chromosome. DAPI is shown in blue. (A) A GFP-bearing chromsome was flipped
against an unmarked chromosome, resulting in wild-type, GFP-labelled clones. (B)
scrib- clones, marked with GFP, remain small in the presence of normal neighbors.
(C) scrib- clones, marked with GFP, in the presence of stat397- cells, grow large. (D)
scrib- clones, marked with GFP, grow large in the presence of stat85c9- cells.
Fig. S4 Proliferation of wts- stat- cells.
Confocal images of eye imaginal discs containing clones of cells of the indicated
genotypes. A GFP-marked chromosome was flipped against an RFP-marked
chromosome. BrdU incorporation, a marker of cells in S-phase, is shown in blue. (A)
wts- clones (RFP+, GFP-) hyper-proliferated. (B) wts- stat- clones (RFP+, GFP-) hyperproliferated. (C) wts- clones (RFP+, GFP-) hyper-proliferated and eliminate scribclones (GFP+, RFP-).
Fig. S5 Stat activity in scrib- clones facing and not facing cell competition.
Confocal images of imaginal discs containing clones of cells of the indicated
genotypes. Cell nuclei are labeled with DAPI (blue). Expression of 10XSTAT-GFP is
shown in green. (A) A wild-type eye disc showing the endogenous expression of
10XSTAT-GFP. (B) scrib- clones, positively marked by RFP expression, do not alter
the level of 10XSTAT-GFP expression. (C) A wild-type wing disc showing the
2
endogenous expression of 10XSTAT-GFP expression in green. (D) scrib-+BskDN
clones, which are protected from elimination by cell competition, are marked by RFP
expression. 10XSTAT-GFP expression shows the levels of Stat activity in the tissue.
scrib-+BskDN clones that are formed near the endogenous expression region of
10XSTAT-GFP can expand the expression region, but clones do not induce Stat
activity consistently.
Fig. S6 Altering levels of Stat signaling does not change Hippo pathway activity.
Confocal images of eye imaginal discs containing clones of cells of the indicated
genotypes. (A) wts- stat- clones, marked by absence of RFP, had low levels of
10XSTAT-GFP reporter (shown in green). (B) Wing disc in which dpp-Gal4 drove
the expression of UAS-GFP (shown in green). ex-lacZ, a reporter of Yki activity, is
shown in red. (C) Wing disc in which dpp-Gal4 drove the expression of UAS-GFP
and UAS-HopTUM1. ex-lacZ expression is shown in red and is unchanged in the region
where Stat has been activated.
Fig. S7 ds-lacZ expression is induced in stat- clones.
Confocal images of eye imaginal discs containing clones of cells of the indicated
genotypes. Expression of ds-lacZ, an insertion into the ds locus that expresses -gal, is
shown in red. (A) Wild-type clones, marked by absence of GFP, showing the
endogenous ds-lacZ expression pattern (B) stat- clones, marked by the absence of
GFP, had elevated ds-lacZ expression, but not consistently.
Fig. S8 Proliferation in stat- clones with and without JNK activity.
3
Confocal images of eye imaginal discs containing clones of cells of the indicated
genotypes. Clones were generated using the MARCM system to positively label
mutant clones by GFP expression (green) and ey-FLP to induce recombination in eye
discs. Cell nuclei are labeled with DAPI (blue) and BrdU incorporation is shown in
red. (A) Clones overexpressing BskDN (+BskDN) showed no proliferation defects. (B)
stat- clones did not hyper-proliferate. (C) stat- clones overexpressing BskDN (stat+BskDN) also proliferated normally.
Fig. S9 scrib- stat- clones overgrow in the presence of M+/- cells, which are poor
competitors.
Confocal images of eye imaginal discs containing clones of cells of the indicated
genotypes. Clones were generated using the MARCM system to positively label
mutant clones by GFP expression (green) and ey-FLP to induce recombination in eye
discs. Cell nuclei are labeled with DAPI (blue). (A) Clones of wild-type cells, marked
by GFP expression, in the presence of M+/- cells. (B) stat- clones, marked by GFP
expression, grew in the presence of M+/- cells while maintaining normal disc
morphology. (C) scrib- clones, marked by presence of GFP, grew large in the presence
of M+/- cells and disrupted the morphology of the disc. (D) Clones of scrib- stat- cells,
marked by presence of GFP, grew large in the presence of M+/- cells and comprised
the majority of the disc.
4