Fallopian tube and uterus by immunohistochemistry. The oviduct epithelium of adult female mouse consists of two types of epithelial cells, which are unevenly distributed. Ciliated cells are predominant in the region of infundibulum and ampulla, and secretory cells in the isthmus. RIC8 was present in all regions of the Fallopian tube. More precisely, in the area of ampulla, it was clearly localized in the basal layer of the cilia of the ciliated cells. RIC8 was also detectable at high level in the epithelium of the isthmus. Interestingly, the localization of RIC8 seemed to be polarized as 5 / 19 Dynamics of RIC8 in Oogenesis Fig 1. RIC8 in folliculogenesis and in the reproductive tract of adult mouse. RIC8 was visualized with RIC8 antibody, and cell nuclei were visualized with DAPI. Transversal cryosections of ovary with oocytes in different follicular stages starting from primordial follicle to Graafian follicle and different regions of oviduct are shown. Higher magnification of the region of ampulla and isthmus. Abbreviations: PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19709857 A, antrum; Amp, ampulla region of oviduct; Cb, basal layer of cilia; Cc, ciliated cell; Ci, cilia; Co, cumulus oophorus; Cr, corona radiata; Cx, cell cortex, Ec, epithelial cells; Fc, follicular cell; Gc, granulosa cells; Gf, Graafian follicle; GV, germinal vesicle; Ist, isthmus region of oviduct; Lp, lamina propria; Lu, lumen; Pc, peg cell; Pf, primary follicle; Pmf, primordial follicle; Po, primary oocyte; Sf, secondary follicle. Scale bars: 50 m. doi:10.1371/journal.pone.0129131.g001 it accumulated more in the apical cell cortex than in basal. RIC8 expression was also detectable in the endometrium of uterus but at the markedly lower level. During Oocyte Maturation RIC8 Accumulates on Chromatin and Meiotic Spindle The final phase of folliculogenesis comprises the resumption of meiosis and germinal vesicle breakdown, which are triggered by a surge of luteinizing hormone. In order to map the RIC8 protein localization after meiotic resumption, we characterized the oocytes at different stages 6 / 
19 Dynamics of RIC8 in Oogenesis Fig 2. TG100 115 chemical information Dynamic changes in localization of RIC8 in the mouse oocyte during meiosis. RIC8 was visualized with RIC8 antibody, microtubules with antibody to tubulin, chromatin with DAPI and F-actin with phalloidin. GV- stage oocyte; GVBD stage oocytes; oocytes undergoing meiosis I or meiosis II. Higher magnification of the region of chromatin. Yellow arrowheads indicate the RIC8 foci at nucleolus and on chromatin. White arrows point to the meiotic spindle. Negative control. Abbreviations: AnaI, anaphase of meiosis I; DON, disappearance of the nucleolus; GV, germinal vesicle; FR, full rim stage; MetI/MetII, metaphase of meiosis I or II; ms, meiotic spindle; PR, partial rim stage; TelII, telophase of meiosis II. Scale bar: 20 m. doi:10.1371/journal.pone.0129131.g002 of meiosis I, and in in vivo fertilized oocytes during meiosis II by using immunocytochemical analysis with RIC8 antibody. Before the germinal vesicle breakdown, dynamic changes take place in the chromatin configuration of germinal vesicle, which are associated with transcriptional activity. The localization of RIC8 was assessed at different maturation stages of nucleus, which were assigned based on the chromatin configuration. First, we discovered that when the chromatin started PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19710274 to condense and it was identified as a partial rim around the nucleolus, RIC8 remained diffusely localized across the germinal vesicle, which was also typica
