Fig. 5. svp mutant R neurons co-express R7 and R8 markers during larval
but not pupal development. Eye discs from wandering third instar larvae
(L3; A-D'') or pupae 25 hours after puparium formation (P25;
E-F''). ey-FLP3.5 and the EGUF/hid method
(Stowers and Schwarz, 1999)
were used to create eyes homozygous for a wild-type (FRT82; A,C,E) or
svp mutant (B-B'',D-D'',F-F'') chromosome. R cell
nuclei were visualized with anti-Elav antibodies (red). Images are all from
the apical region of the disc, which contains the R7 nuclei; R8 nuclei are not
visible, except as noted in B. A proportion of R1/R6 and R3/R4 nuclei are
visible. (A-B'') L3 eye discs were labeled with antibodies against the R7
and R8 marker Sal (green) and the R8 marker Sens (blue). Images are from row
20. (A) In wild-type L3 eye discs, R7s express Sal but not Sens, and R1/R6s
and R3/R4s express neither. R8s (not visible) express both. (B-B'') In
svp mutant L3 eye discs, most R1/R6s (solid circles) express Sal;
some co-express Sens. R7s (asterisks) express Sal but not Sens, and R8s (the
single visible R8 is marked with a carat) express Sal and Sens, as in the wild
type. R3/R4/MCs (dashed circles) can also express either both Sal and Sens or
Sal alone. (C-D'') L3 eye discs were labeled with antibodies against the
R7 marker Pros (green) and the R8 marker Sens (blue). Images are from row 20.
(C) In wild-type L3 eye discs, R7s express Pros but not Sens, R1/R6s and
R3/R4s express neither, and R8s (not visible) express Sens but not Pros.
(D-D'') In svp mutant L3 eye discs, most R1/R6s (solid circles)
express Pros or Sens, and some express both (arrowhead). R7s (asterisks)
express Pros only, and R8s express Sens only (not shown). R3/R4/MCs (dashed
circles) can also co-express Pros and Sens (arrows). (E-F'') P25 eye
discs were labeled with antibodies against Pros (green) and Sens (blue). (E)
In wild-type P25 eye discs, R7s express Pros, and R8s (not shown) express
Sens. (F-F'') In svp mutant P25 eye discs, svp mutant R
neurons express either Pros or Sens but only rarely both (arrow). The
disorganization of the svp disc at this stage prevents unambiguous
identification of R1/R6 versus R3/R4 versus R7 neurons, but each ommatidium
contains extra Pros or Sens-expressing R cells (see text). Scale bar: 5
µm.