Gene expression profiling during early folliculogenesis in the mouse ovary.
OBJECTIVE
To evaluate genes involved in ovarian primordial-to-primary follicle transition.


METHODS
Experimental animal study.


METHODS
Research institute.


METHODS
Day-2 and day-4 female Swiss mice.


METHODS
We conducted a complementary DNA array study using ovarian messenger RNAs from day-2 and day-4 mice.


METHODS
The expression profiles of 1,176 genes in neonatal mouse ovaries on day 2 and day 4, which contain primordial and primary follicles, respectively, were compared.


RESULTS
Twenty-six percent of genes were differentially expressed between day-2 and day-4 ovaries, with 19% being up-regulated and 7% down-regulated in day 4. Analysis of differentially expressed genes revealed that the primordial-to-primary follicle stage transition is associated with induction in the expression of mainly growth factors, immune-related factors, hormone and hormone receptors, and signal transducers. The transition is also associated with proliferation of granulosa cells and absence of apoptosis. In addition, our studies demonstrated that the primary follicles express estrogen receptor beta and are responsive to estrogen actions in vitro in terms of increase in the number of primary follicles and granulosa cell proliferation.


CONCLUSIONS
The transition of primordial to primary follicles is associated with the participation of multiple pathways in regulating gene expression.
Dharma
Shalmali J
SJ
National Institute for Research in Reproductive Health, Parel, Mumbai, India.
Modi
Deepak N
DN
Nandedkar
Tarala D
TD
D000818:Animals; D000831:Animals, Newborn; D002450:Cell Communication; D018797:Cell Cycle Proteins / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006133:Growth Substances / Q000235:genetics; D020287:In Situ Nick-End Labeling; D051379:Mice; D009857:Oncogenes / Q000235:genetics; D006080:Ovarian Follicle / Q000033:anatomy & histology / Q000502:physiology*; D010053:Ovary / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D011987:Receptors, Steroid / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D004967:Estrogens; D006133:Growth Substances; D011987:Receptors, Steroid; D012313:RNA