Fig. 2. Verification of transgene expression by probing for the MYC tag. (A) RT-PCR amplified a segment of the MYC-encoding sequence (upper band, 420 bp) from oocyte RNA, but not granulosa cell RNA, of both transgenic lines. A segment of mRNA encoding glyceraldehyde phosphate dehydrogenase (GAPDH; lower band, 299 bp) was amplified as a positive control. WT, wild-type ovary; blank, negative control (no template). (B) The MYC epitope (upper band) was detected by western blotting in ovaries of both transgenic lines, but not in ovaries of Cx37-knockout (Cx37 KO) or wild-type (WT) mice. The lower band is GAPDH (loading control). (C) Immunostaining for the MYC epitope in ovary sections revealed its localization at the oocyte surface in connexin-replacement mice and its absence from wild-type or Cx37-deficient mice. Oocytes are indicated by arrows. Bar, 30 µm.