The sev promoter drives expression of the pk[sple] isoform of pk.
pksple.sev rescues pkpk-sple-13
pksple.sev rescues pksple-1
The presence of pksple.sev in the R3/R4 photoreceptor precursor pairs always leads to rescue of the pkpk-sple-13 or pksple-1 phenotypes.