Figure 1. Localization of Rspo1 transgene in XY medaka embryos and adults.

Rspo1-GFP expression (arrowheads) in gonads of Rspo1 overexpressed XX (A) and XY (B) at 5 dah. Strong Rspo1-GFP expression is also seen in the brain (C) at 5 dah. In adults, GFP fluorescence (marked with white arrow head) is found in various gonadal cells (D). Photographs were taken from F₁ generation embryos and F₀ adults. Multicolor- fluorescent in situ hybridization FISH shows that Rspo1 (green) expresses in germ cells and germ cell surrounding cells of 10 dah Rspo1-OV-XY fish in which either Foxl2 (red) or Gsdf (yellow) expressions are evident (E). The representative Foxl2-Gsdf and Rspo1-Gsdf expressing somatic cells are respectively marked with white and pink arrowheads in the inset. The yellow dotted line represents candidate germ cells. Similar analysis shows that, Rspo1 (magenta) mRNAs are congregated in the young oocytes, early germ cells and early germ cell surrounding cells at 60 dah (F). The representative Foxl2-Rspo1 expressing early germ cell surrounding cells are marked with white arrowhead in the inset.