• Asian-Australasian Journal of Animal Sciences
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• 제30권6호
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• pp.781-787
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• 2017

Objective: The early growth response (Egr) family consists of four members (Egr1, Egr2, Egr3, and Egr4) that are zinc finger transcription factors. Among them, Egr3 is involved in transcriptional regulation of target genes during muscle spindle formation and neurite outgrowth. We previously showed that the immunoreactive Egr3 is localized on oocyte spindle and accumulate near the microtubule organizing center during meiosis I in mice. Egr3 was also shown to be localized on spermatocytes. We herein investigated if Egr3 is expressed in mouse gonads and if Egr3 blockade results in any defect in oocyte maturation. Methods: Expression of Egr3 in mouse gonads was examined by reverse transcription-polymerase chain reaction. Full-length Egr3 and truncated Egr3 (${\Delta}Egr3$) complementary RNAs (cRNAs) with Xpress tag at N-terminus and DsRed2 at C-terminus, and small interfering RNA (siRNA) targeting Egr3 were microinjected into mouse oocytes at germinal vesicle stage. Localization of microinjected Egr3 was examined by confocal live imaging and immunofluorescence staining. Results: Egr3 mRNA was detected in mouse ovaries and testes from 1 to 4 week-old mice. An uncharacterized longer transcript containing 5'untranslated region was also detected in 3 and 4 week-old gonads. Microinjected Xpress-Egr3-DsRed2 or Xpress-${\Delta}Egr3$-DsRed2 localized to nuclei and chromosomes during meiotic progression. Microinjection of these cRNAs or Egr3 siRNA in oocytes did not affect meiotic maturation. Immunofluorescence staining of Egr3 in Xpress-${\Delta}Egr3$-DsRed2-injected oocytes showed a positive signal only on meiotic spindle, suggesting that this antibody does not detect endogenous or exogenous Egr3 in mouse oocytes. Conclusion: The results show that Egr3 localizes to chromosomes during meiotic progression and that certain antibodies may not faithfully represent localization of target proteins in oocytes. Egr3 seems to be dispensable during oocyte maturation in mice.

• Reproductive and Developmental Biology
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• 제37권4호
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• pp.193-197
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• 2013

In order to investigate the effects of antioxidants on the culture of mouse preantral follicles in vitro, we examined the effects of taurine, glutathione and catalase on their growth and maturation. Addition of taurine was not effective on the survival of preantral follicles. However, metaphase II rates of oocytes within preantral follicles were significantly higher in 1 mM treated group than in control and 10 mM treated group (p<0.05). Glutathione did not improved the rates of survival and metaphase II oocytes. However, metaphase II rates of oocytes progressively decreased with increasing glutathione concentration. Catalase also showed that the rates of survival and metaphase II oocytes progressively decreased with increasing concentration. Especially, all of preantral follicles cultured in medium containing 100 IU/ml catalase were degenerated. These results suggest that low concentraion of taurine, as an antioxidant, have positive effect on the culture of mouse preantral follicles in vitro.

• 한국발생생물학회지:발생과생식
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• 제1권1호
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• pp.45-56
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• 1997

Befor fertilization, mammalian oocytes undergo meiotic maturation, which consists of nuclear and cytoplasmic differentiation. In this study, changes of $Ca^{2+}$ stores in mouse oocytes were examined during meiotic maturation and the role of $Ca^{2+}$ in the regulation of the maturation was investigated by using monoclonal antibodies against smooth endoplasmic reticulum $Ca^{2+}$-ATPase(SERCA-ATPase) and calreticulin. Observations were made under epifluorescence microscope and/or confocal laser scanning microscope. In immature oocytes which did not resume meiotic maturation, SERCA-ATPases were mostly localized in the vicinity of the germinal vesicle and calreticulins were distributed evenly throughout the cytoplasm. In mature oocytes, SERCA-ATPases were observed throughout the cytoplasm, butwere absent from the nuclear region. In contrast, calreticulins were localized mostl in the cortex of the oocyte and were absent from the cytoplasm. However, bright fluoresence stainings were wbserved in the perimeiotic spindle region of mature oocyte when labeled with antibodies against calreticulin. These results indicate that mouse oocytes undergo distinct rearrangement of the localization of $Ca^{2+}$-ATPases and calreticulins during meiotic maturation. Thus it can be suggested that redistribution of the $Ca^{2+}$ stores, as revealed by differential fluorescence stainings, is deeply involved in the regulatory mechanism of mammalian oocyte maturation.

• 한국발생생물학회지:발생과생식
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• 제4권2호
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• pp.243-250
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• 2000

To find the mechanism underlying the ADP-induced increase in the outward current in ovulated mouse oocytes, we examined changes in voltage-dependent currents using the whole cell voltage clamp technique and the internal perfusion technique. Eggs were collected from the oviduct of superovulated mice with PMSG and hCG. Membrane potential was held at -60 mV (or -80 mV in the case of recording $Ca^{2＋}$ currents) and step depolarizations or hyperpolarizations were applied for 300 ms. By step depolarizations, outward currents comprising steady-state and time-dependent components were elicited. They were generated in response to the positive potential more than 20 mV with severe outward rectification and were blocked by external TEA, a specific $K^{＋}$ channel blocker, suggesting that they be carried via $K^{＋}$ channels. Internally-perused 5 mM ADP gradually increased outward $K^{＋}$ currents (IK) 1 min after perfusion of ADP and reached slowly to maximum (150~170％) 5 min later over the positive potential range, implying that ADP might not be acted directly to the $K^{＋}$ channels. IK were decreased by 5 mM ATP without affecting the steady-state component of outward current. In contrast to the effect of ADP and ATP on IK, both effect of ATP and ADP on inward $Ca^{2＋}$ currents (ICa) could not be detected due to the continuous decrease in current amplitudes with time-lapse ("run-down" phenomena). To check if there is a G protein-involved regulation in the ionic current of mouse oocytes, 1 mM GTP was applied to the cytoplasmic side, and the outward current and inward currents were recorded. ICa was promptly increased in the presence of GTP whereas IK was not changed. from these results, it is concluded that the ATP-dependent regulation is likely linked in the ADP-induced increase in the outward $K^{＋}$ current, and G protein-involved cellular signalling might affect ion channels carrying $Ca^{2＋}$ and $K^{＋}$ in mouse oocytes.

• 한국발생생물학회지:발생과생식
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• 제11권1호
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• pp.21-29
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• 2007

본 연구진은 선행 연구에서 progesterone receptor membrane component 2 (pgrmc2) 유전자가 미성숙 난자에서 높게 발현하는 것을 발견하였다. 본 연구는 pgrmc2와 pgrmc1 유전자가 쥐의 생식소와 배아의 발달 단계에 따라 어떻게 발현하는지 알아 보기 위해 수행하였다. 이들 유전자는 난소, 정소, 배아, 그리고 난자의 다양한 발달 단계에서 발현하는 것을 알 수 있었다. 쥐 난자 세포막에 프로게스테론 수용체가 존재하는 것은 progesterone-3-O-carboxymethyl oxime-BSA-fluorescein isothiocyanate (P4-BSA-FITC)의 결합을 이용하여 확인하였다. 본 결과는 프로게스테론 수용체의 세포막 구성 요소들이 생쥐의 난자, 배아, 그리고 생식소에서 발현함을 최초로 확인한 연구 결과다. 스테로이드 수용체의 세포막 구성 요소들의 기능, 특히 프로게스테론 수용체의 세포막 구성 요소들의 기능을 알아 보기 위해 추후 연구가 계속되어야 할 것이다.

• Reproductive and Developmental Biology
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• 제31권2호
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• pp.71-76
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• 2007

Previous studies have shown that BMI-1026 is a potent inhibitor of the cyclin-dependent kinases (cdk). In cell culture, the compound also arrests G2/M strongly and G1/S and S weakly. Two key kinases, cdk1 (p34cdc2 kinase) and mitogen-activated protein (MAP) kinase (erk1 and 2), perform crucial roles during oocyte maturation and, later, metaphase II (MII) arrest. In mammalian oocytes, both kinases are activated gradually around the time of germinal vesicle breakdown (GVBD) and maintain high activity in eggs arrested at metaphase II. In this study, we examined the effects of BMI-1026 on GVBD and MII arrest in mouse oocytes. BMI-1026 inhibited GVBD of immature oocytes and activated MII-arrested oocytes in a concentration-dependent manner, with more than 90% of oocytes exhibiting GVBD inhibition and MII activation at 100 nM This is approximately 500$\sim$1,000 times more potent than the activity reported for the cdk inhibitors roscovitine (${\sim}50{\mu}M$) and butyrolactone (${\sim}100{\mu}M$). Based on the results of previous in vitro kinase assays, we expected BMI-1026 to inhibit only cdk1 activation in oocytes and eggs, not MAP kinase. However, in our cell-based system, it inhibited the activity of both kinases. We also found that the effect of BMI-1026 is reversible. Our results suggest that BMI-1026 inhibits GVBD and activates MII-arrested oocytes efficiently and reversibly and that it also inhibits both cdk1/histone HI kinase and MAP kinase in mouse oocytes.

• 한국가축번식학회지
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• 제19권4호
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• pp.323-329
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• 1996

미성숙난자 성장과 핵성숙을 성공적으로 유도할 수 있는 체외 배양체계의 개발은 난자발생과정 등 기초 생리학 연구에 도움을 줄 뿐만 아니라, 산업적으로 필요한 난자를 공급해 줄 수 있다는 데 그 의의가 있다. 최근 보고에 따르면 성장 중에 있는 생쥐 난포란은 체외배양과 체외수정과정을 거쳐 산자 생산가지 가능하지만 돼지 난포란 성숙을 위해서는 좀더 고려해야 할 사항들이 있다. 즉, 난성숙 배양액에 낮은 농도의 FSH 첨가는 난자와 과립세포의 생존성을 유지시키고, Hypoxanthine의 첨가는 난성숙율의 향상에 도움을 준다고 한다. 따라서 금후 생쥐난자에서 얻어진 결과들을 기초로 하여 돼지 난포란의 성장과 성숙에 적합한 배양체계의 개발연구에서 괄목할만한 진전이 있다면 대가축들의 난포란 성숙기술을 개발하는데 큰 도움을 줄 것이라고 본다.

• 한국동물학회지
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• 제28권2호
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• pp.99-107
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• 1985

생쥐난자의 성숙을 억제하는 것으로 알려진 dbcAMP와 progesterone을 동시에 처리하였을 때의 영향을 알아보기 위하여 본 실험을 행한 결과는 다음과 같다. 1) 10 $\\muM$/ml의 dbcAMP 혹은 2 $\\muM$/ml의 progesterone을 단독처리하였을 때에는 난자의 성숙을 억제하지 못했다. 2) 그러나 dbcAMP(10 $\\mug$/ml)와 progesterone(2 \\mug$/ml)을 동시에 배양액에 처리하였을 때에는 난자의 성숙이 억제되었다. 3) 난자를 먼저 4시간동안 위의 두 억제제가 들어있는 배양액에서 배양한 뒤 다시 정상배양액에 옮겨 계속 배양하면 나자들은 대조군에서와 같은 비율로 성숙을 하였다. 위의 결과로 보아 dbcAMP와 progesterone이 동시에 배양액에 존재할 때에는 각각 단독 존재하였을 때 영향이 없는 농도의 dbcAMP와 progesterone으로도 능히 난자의 성숙을 억제 시킬 수 있었으며 이 같은 억제효과는 가역적임을 알게되었다.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.61-61
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• 2003

We have investigated the novel function of tissue transglutaminase (tTG) in the germinal vesicle breakdown (GVBD) of mouse oocyte. tTG was identified in ooplasm and germinal vesicle by immunostaining assay. Spontaneous maturation of the oocytes elevated in situ activity of tTG by over 2.5 fold at 3 hr, which was determined by a confocal microscopic assay. However, incubation with monodansylcadaverine (MDC), a tTG inhibitor, blocked the activation of tTG. The possible role of tTG in GVBD was investigated by the use of two tTG inhibitors, MDC and cystamine. MDC largely inhibited the GVBD by a concentration dependent manner. GV-stage oocytes were matured to the GVBD stage by 78% at 3 hr in BWW culture medium. However, in the oocytes incubated with MDC for 3 hr, the GVBD rates were 43 and 11% by 50 and 100 mM, respectively. MDC also blocked the entry of 70 kDa TRITC-dextran from the ooplasm to the compartment of germinal vesicle, indicating a possible inhibition of nuclear pore disassembly by MDC. The role of tTG in GVBD was further investigated by microinjection with cystamine. The control oocytes, injected with DPBS, showed about 80 % of GVBD at 3 hr. But the oocytes injected with cystamine showed 15% of GVBD at 3 hr and a little higher rate at 6 hr. In addition, the inhibition of GVBD maturation by MDC was reversible by washing. These results suggested that tTG was involved in the early event of mouse oocyte maturation

• 한국가축번식학회지
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• 제17권2호
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• pp.93-101
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• 1993

These experiments were carried out to investigate whether zona hardening affect the efficiency of in vitro fertilization in mouse oocytes. The soluble properties for zona pellucida of oocytes matured in vivo, aged oocytes, and ovarian oocytes matured in vitro have been analyzed with proteolytic enzyme, 3mg/ml of $\alpha$-chymotrypsin. The mean solubility(t50) for the zona of unfertilized oocytes, oocytes not fertilized at the first inseminati and in vitro produced zygotes were 10.1, 20.3 and 32.3min., respectively. The t50 for zona lysis of fertilized oocytes was significantly difference than those observed for unfertilized oocytes and oocytes not fertilized at the first insemination(P<0.01). In addition, the t50 of zona in ovulated oocytes with and without cumulus cells incubated for 0, 3, 6, 9 and 12 hr in vitro, t50 were 13.9, 11.1, 20.7 and 28.0min., and 22.3, 21.0, 30.0 and 33.5min., respectively. In these experiments, the zona pellucida showed a gradual increase in resistance to dissolution by $\alpha$-chyjotrypsin with in vitro aging for more than 6 hrs. This effect was greater in cumulus-free as compared to cumulus-intact oocytes. Finally, in cumulus-intact and cumulus-free ovarian oocytes matured for 0, 5, 10 and 15 hr in vitro the t50 of zona pellucida were 3.0, 10.6, 18.4 and 24.5 min., and 3.0, 14.0, 26.2 and 32.0 min., respectively. Clear differences in solubility between the zona pellucida of oocytes matured in vivo and in vitro. This data were found suggest that under in vitro conditions there is a gradual change in the soluble properties of the zona pellucida, particularly in the absence of the cumulus cells.