Fig 8. Schematic scheme of the main genetic and molecular signal dynamics detected in ovarian cells during follicle assembly.

The upper panel indicates the genetic programs and key biological events of germ cells and pre-granulosa cells during germline nest breakdown and follicle assembly, and the developmental time courses are indicated above; the orange box contains the marker genes and their expression dynamics in germ cell; the green ones comprise the marker genes and their expression dynamics in pre-granulosa cell. The dark orange dashed line separates ovarian cortex (above) from the medulla, labeled with 2 sources of pre-granulosa cells, i.e., BPG cells for the first wave in ovarian medulla and EPG cells in ovarian cortex for the second wave of follicle formation, respectively. In the bottom panel (upper part), the activation of 5 main interactive pathways between germ cells and granulosa cells during these processes is represented. In the lower part, the stage-specific TFs in oocytes from nest to follicle stage are reported. BPG, bipotential pre-granulosa; EPG, epithelial pre-granulosa; TF, transcriptional factor.