Figure 5

In situ hybridization and immunological staining of the three major BbZPs (BbZP1, BbZP3 and BbZP4) in ovary sections of adult B. belcheri samples. (A). In situ hybridization showing the predominant localization of mRNAs of BbZPs in the developing (immature, smaller-sized) oocytes (the cells in blue) in the ovary of the adult amphioxus. No hybridization signal was detected in the developed, larger-sized oocytes (in the light grey colors). Typical immature oocytes are indicated by a red ‘n’, whereas typical mature ones by a black ‘m’. Green arrows indicate the follicle cells with positive signals. (B). Immunological localization of the three major ZP proteins in the egg surface (red arrows) and cortical granules (black arrows) in adult amphioxus. Panel a shows the negative control, in which pre-immune rabbit serum was used to replace the first antibody in immunochemical staining. Black ‘m’ and red ‘n’ indicate typical mature and immature oocytes, respectively.