Fig. 6. Expression of Fgf8b mRNA in oocytes. (A) Fgf8 mRNA was detected in oocytes in ovaries of both 12-day-old (12 day) and 22-day-old eCG-primed (22 day eCG) mice by in situ hybridization. (Left) Brightfield images. (Right) Darkfield images. Scale bar: 500 µm. (B) Schematic diagram of eight different Fgf8 isoforms, Fgf8a-h [modified from MacArthur et al. (MacArthur et al., 1995a)]. Positions of PCR primers used are indicated in the expanded region. (C) Oocyte cDNA were amplified with PCR and the products were separated by agarose electrophoresis. A representative gel photograph after ethidium bromide staining is shown. Approximate sizes are shown on the y-axis (bp). The numbers in parentheses indicate expected size of PCR products (bp).