Figure 7

Similar distribution of nanos1A and nanos1B transcripts in germ cells and in follicular cells in dogfish ovary. The localization of nanos1 mRNAs was determined in ovaries by in situ hybridization using antisense digoxigenin-conjugated riboprobes directed against nanos1A (A–D) or nanos1B transcripts (A’–D’). E and E’ represent results obtained with sense riboprobes for nanos1A and nanos1B respectively. The nanos1A transcripts were detected in primary oocyte of primordial follicles (around 100 µm in Ø illustrated in A). This labelling progressively decreased during oocyte growth until being undetectable in previtellogenic follicles (around 300 µm in Ø illustrated in (B). The mRNAs were also detected in the granulosa cells (GC) and the outer theca cells (oTC) of early (C) and the more advanced (D) vitellogenic follicles (around 500 µm and >2 mm in Ø respectively). The same expression profile was detected for nanos1B with an expression in primary oocyte of primordial follicles (A’), in granulosa (GC) and outer theca cells (oTC) of early (C) and more advanced (D) vitellogenic follicles. In previtellogenic follicle (B’), nanos1B was still detectable in oocyte cytoplasm. b: blood cells, BL: basal lamina, GC: granulosa cells, N: nucleus, n: nucleolus, Oo: primary oocyte, TC: theca cells, iTC: inner theca cells, oTC: outer theca cells, Y: yolk, ZP: zona pellucida.