St. 17 gonads immunostained as indicated in the figure. Anterior is to the left in each panel. (A) Expression of the svp-lacZ fat body enhancer trap overlaps with SOX100B-positive PC precursors. (B) Cells that express the PC precursor marker Kr-GAL4, UAS-GFP also express SRP. (C) A srp mutant gonad that lacks PC precursors but has msSGPs (co-expressing SOX100B and EYA, arrow). (D,E) EMS is expressed in cells that ensheath the male (D), but not female (E) embryonic gonad. (F,G) SOX100B-positive PC precursors surround the wild-type male gonad (F, arrowhead) but are not observed in ems mutant gonads (G), which only exhibit SOX100B expression in msSGPs (arrow).