EMB-9 is secreted from the body wall muscle cells and localizes to the BM. An antibody against EMB-9 clearly stained gonadal and intestinal BMs in wild-type hermaphrodites at the third and fourth larval stages (L3 and L4, respectively). EMB-9 accumulation in
fbl-1(
tk45) mutants was normal at L3 but was markedly reduced and punctate at L4. These results suggest that FBL-1 is not required for gonadal accumulation of EMB-9 prior to L4, but for maintaining EMB-9 localization in the gonadal BM during the late larval stages.