Fig. 5. A dgn-1 null mutant is viable but sterile due to early gonad disruption. (A,B). Wild-type (A) and homozygous dgn-1(cg121) null mutant (B) adults. Gonad tissue in cg121 forms a disorganized mass (white outline) and the vulva protrudes (arrowheads). (C) Wild-type four-cell gonad primordium with two central PGCs (asterisk) and two SGPs surrounded by a BM creating a sharp DIC boundary. (D) Newly-hatched cg121 homozygotes retain a compact primordium but have mispositioned SGPs, a weak DIC boundary and bulging PGCs. (E) Ruptured gonad primordium of a cg121 L1 larva; gonadal cells spread along the body wall (white outline). (F) Early epi-1(rh199) laminin B L1 larva showing similar rupture of the primordium (white outline). (G) Normal gonad primordium in dys-1(cx18) dystrophin mutant L1 larvae. (H) Percentage of mispositioned SGPs in newly-hatched dgn-1(cg121) (n=104) and epi-1(rh199) (n=58) larvae. (I) Overlay of DIC and lag-2::GFP images of wild-type gonad (black outline) at early L2 stage. Somatic gonad cells expressing lag-2::GFP (green) are in close association with germ cells (asterisks). (J,K) DIC/lag-2::GFP overlays of gonads in early L2 stage dgn-1(0) animals. (J) In 60% (n=25) of animals, somatic gonad cells (white outline) form a central cluster separated from, or in only peripheral contact with, germ cells (asterisks). (K) In 40% of animals, somatic gonad cells adopt a contiguous linear arrangement along the ventral surface, sometimes split into two clusters. In I-K, additional lag-2::GFP signal from non-gonadal cells is visible along the ventral midline. Scale bar: 10 µm.