Recruitment of primordial follicles(PMF) is crucial for female fertility. however, factors and mechanisms that regulate this process is poorly understood. The present study was conducted to obtain an inclusive view of the gene expression and to identify novel factors and their pathways of regulating PMF arrest and/or growth initiation. Ovaries from one-day neonatal(consists of oocyte and PMF) and five-day old(consists of PMF and primary follicles, PRIF) mice were collected, either total RNA or mRNA was isolated, and suppression subtractive hybridization(SSH) was used to isolate and clone genes that differentially expressed in day 1 and day 5 ovaries. Confirmation that some of these genes are differentially expressed in PMF and/or in PRIF was accomplished by using laser captured microdissection(LCM), RT-PCR. in situ hybridization(ISH) and/or immunohistochemistry(IHC). In toto, 357 clones were sequenced and analyzed by BLAST and RIKEN program. Sequences of 330 clones significantly matched database entries while 27 clones were novel. Forty-two and 47 different genes were identified as differentially expressed in day 1 and day 5 ovaries, respectively, while 7 genes were expressed in both stages of ovaries. Day 5-subtracted library included several genes known as markers far growing follicles, such as ZP2, MATER, and fetuin. Among the genes with assigned functions, 23.8% was associated with cell cycle/apoptosis regulation, 7.1% with cellular structure, 11.9% with metabolism, 26.2% with signal transduction, and 31.0% with gene/protein expression in day 1; while 10.6%, 17.0%, 23.5%, 25.5%, and 23.4% in day 5, respectively. Genes such as GDF-8, Lats2, Septin2, and Weel were the highly expressed genes in PMF, while HSP84, Laminin2, MATER, MTi7, PTP, and Wrn were highly expressed genes in PRIF. We have successfully discovered list of genes expressed in day 1 and day 5 ovaries and confirmed that some of them are differentially expressed in PMF and/or PRIF. Gene expression profile from the present study would provide insight for the future study on the mechanism(s) involved in primordial-primary follicular transition. This work was Supported by Korean Health 21 RND Project, Ministry of Health and Welfare, Korea (01-PJ10-PG6-01GN13-0002).

Transition of the resting primordial follicle to the growing primary follicle is a critical process for female reproduction, but its mechanism is poorly understood. The present study was conducted to investigate gene expression profile at the primordial-primary follicle transition process. We isolated total RNA of female mouse ovary at day1 (contains only primordial follicles) and day5 (contains primordial and primary follicles) and synthesized cDNA using annealing control primers (ACP; Seegene, Inc., Seoul, Korea). ACP provides annealing specificity and sensitivity to the template and allows to identify only authentic differentially expressed genes (DEGs). We used total 80 ACPs for PCR, observed PCR products on 2% agarose gel, cloned 42 DEGs using TOPO TA cloning vector, sequenced, and analyzed by BLAST search. Sequences of 34 clones significantly matched database entries while 4 clones were novel and 4 clones were EST. Two of 34 genes were specifically expressed only in day 5 ovaries (Sui1-rs1, Apg3p/Aut1p-like), and rest of 32 genes were expressed in both stages but were differential in amount. Differential expression was confirmed using semiquantitative RT-PCR, and there was no false positive. Anx11 and Pepp2-pending were highly expressed genes in day1-, while BPOZ, Ches1, Kcmf1, NHE3, Nid2, Ninj1, SENP3 and Survivin were highly expressed genes in day5-ovary. List of genes would provide insight for further study of mechanism regulating primordial-primary follicle transition.

성장을 멈추고 있는 원시난포(primordial follicle)에서 난포발달이 개시되어 1차난포(primary follicle)로 발달하는 조절기전은 잘 알려져 있지 않다. 이 초기 난포발달 과정에 관여하는 유전자를 알아내기 위해 suppression subtractive hybridization(SSH)을 사용하였다. 생후 1일과 5일째의 생쥐 난소로부터 얻은 cDNA로 forward와 reverse subtraction을 수행하여 각각 day1과