Interestingly, a lot of primordial follicles were observed with strong PAR6 staining in the nuclei of oocytes when the ovaries treated with CBX for 4 days were transferred to a new culture medium without CBX for 4 more days. These results Prothionamide indicate that the effect of CBX can be Pranoprofen rescued, and reexpression of PAR6 in the oocyte needs the establishment of gap junctions. Similarly, the expression of Figa gene obviously decreased after treatment with CBX for 4 days, and further decreased for 8 days treatment, but was completely recovered when the ovaries, which had been treated with CBX for 4 days, were cultured further without CBX for 4 more days. The PAR6 in germ cells might not be transferred from somatic cells via gap junctions which could only allow inorganic ions, second messengers, and small metabolites to pass from cell to cell. In our study, CBX treatment inhibited the expression of PAR6 in germ cells possibly by blocking the signals from somatic cells to germ cells, since in Drosophila the signals from somatic cells to germ cells are required for the expression of PAR. CBX also blocked the formation of primordial follicles possibly by inhibiting the expression of PAR6 for that eliminating the function of PAR6 by anti-PAR6 antibody and RNAi produced similar phenotypes of reducing the number of primordial follicles. In Drosophila, signals from the germ cells control the migration and differentiation of the somatic cells. It needs further investigation whether the germ cells with the expression of PAR6 give the signals to the somatic cells through the gap junction and induce them to wrap up the germ cells to form primordial follicles in mice. It is interesting that the expression of PAR6 in somatic cells was strong at the early stage, but weak when the somatic cells began to incorporate the cysts at 17.5 dpc. On the contrary, the nuclei of primordial follicular oocytes strongly expressed the PAR6 permanently. GCNA is widely used as a marker for germ cells of fetal and neonatal mouse ovaries, but it is not detected in oocytes which are arrested at the diplotene stage of meiosis I. The PAR6 is an alternative marker for somatic cells before 17.5 dpc and for primordial follicles from the cradle to the grave.