Gene expression profiling of early follicular development in primordial, primary, and secondary follicles

To study global gene expression profiles of early folliculogenesis in primordial, primary, and secondary follicles. A cDNA microarray study using amplified RNAs from isolated follicles. Experimental animal study. Female ICR strain mice (12 days old). Isolation of follicles at each stage, RNA isolation and amplification, microarray hybridization, and statistical analysis for microarray. Gene lists of various functional groups with an estimated false discovery rate of 5%. Among them, platelet-derived growth factors (PDGFs) and receptors were localized by immunohistochemistry in mouse ovaries. We analyzed a list of genes according to function, such as apoptosis, cell cycle, cell proliferation and maintenance, cytoskeleton, extracellular matrix, and signal transduction, as well as according to frequency. Among the list of genes, we found all PDGFs (A, B, C, and D) and receptors (α and β) are expressed with differential expression patterns in the oocytes and ovarian cells according to stage of follicular development. The present report suggests that genome-wide expression profiling using microarray after RNA amplification may become a useful tool to better understand the molecular mechanism(s) involved in early ovarian folliculogenesis.