YP170:: GFP accumulates in vesicles of the oocyte. (A) Whole adult hermaphrodite expressing YP170::GFP. YP170::GFP fluorescence is found in the intestine, late-stage oocytes, and embryos. YP170::GFP localization appeared very similar to endogenous YP170 by fluorescence microscopy (this work) and immuno-electron microscopy (Hall et al., 1999). Immuno-electron microscopic experiments did reveal accumulation of YP170::GFP in enlarged vesicles of the intestine, unlike endogenous YP170 in wild-type worms (Hall et al., 1999). Such accumulation may result from overexpression of YP170 in transgenic strains or properties acquired from the GFP tag. OO, late-stage oocytes; V, vulva. (B) Confocal micrograph of YP170::GFP vesicles within two nearly full-grown oocytes of one gonad arm. (C) Confocal micrograph of YP170::GFP vesicles within a two-cell embryo. (D) Stylized drawing of one gonad arm connected to the spermatheca and the uterus.