Differential gene expression in transition of primordial to preantral follicles in mouse ovary.
In the mammalian ovary, early follicular development is gonadotropin independent. Interaction between the oocyte and granulosa cells possibly plays an important role in transition of primordial to preantral stage. However, the molecular and cellular control of early follicular development and cell-cell interaction is complex and poorly understood. In the present study, we examined gene expression in primordial, primary and preantral follicle by cDNA arrays using Day 2, Day 4 and Day 6 neonatal mouse ovaries that contain the various developmental stages of these follicles, respectively. The results revealed that 30% of the genes were differentially expressed in Day 4 ovaries containing primary follicles as compared to D2 neonatal ovaries. The data were confirmed by the expression of Growth Differentiation Factor-9 in the oocytes of primary and preantral follicles. Also, Stem Cell Factor was localized in the granulosa cells of primary and preantral follicles. Electron microscopic studies of Day 6 ovaries showed projections from granulosa cells and microvilli from oocytes in the follicle during the transition from the primary to preantral stage. Further, initiation of gap junctions were observed at ultrastructure level and corroborated with the expression of specific gap junction protein, connexin 43 in preantral follicles of the ovaries. These results infer that primordial follicles are quiescent while the major activities of cell-cell communication and the production of local paracrine factors, are initiated in primary and preantral follicles of the mouse ovary. These preliminary observations may contribute to the elucidation of molecular and cellular pathways involved in follicle transition.
Nandedkar
Tarala
T
National Institute for Research in Reproductive Health (ICMR), Parel, Mumbai 400 012, India. cellbioirr@rediffmail.com
Dharma
Shalmali
S
Modi
Deepak
D
Dsouza
Serena
S
D000818:Animals; D000831:Animals, Newborn; D055430:Bone Morphogenetic Protein 15; D002450:Cell Communication; D018031:Connexin 43 / Q000032:analysis / Q000235:genetics; D005260:Female; D017629:Gap Junctions / Q000378:metabolism; D015870:Gene Expression; D020869:Gene Expression Profiling; D006107:Granulosa Cells / Q000378:metabolism; D055429:Growth Differentiation Factor 9; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis / Q000235:genetics; D051379:Mice; D008815:Mice, Inbred Strains; D008854:Microscopy, Electron; D020411:Oligonucleotide Array Sequence Analysis; D009865:Oocytes / Q000378:metabolism / Q000648:ultrastructure; D006080:Ovarian Follicle / Q000166:cytology / Q000502:physiology*; D019899:Paracrine Communication / Q000502:physiology*; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis / Q000235:genetics; D019089:Stem Cell Factor / Q000032:analysis / Q000235:genetics
C525902:Bmp15 protein, mouse; D055430:Bone Morphogenetic Protein 15; D018031:Connexin 43; C525898:Gdf9 protein, mouse; D055429:Growth Differentiation Factor 9; D036341:Intercellular Signaling Peptides and Proteins; D018809:Proliferating Cell Nuclear Antigen; D019089:Stem Cell Factor