• Asian-Australasian Journal of Animal Sciences
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• v.25 no.6
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• pp.789-793
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• 2012

Fertilization of the oocyte commences embryogenesis during which maternally inherited mRNAs are degraded and the embryonic genome is activated. Transcription of embryonic mRNA is initiated by embryonic genome activation (EGA). RNA polymerase II (RNA Pol II) is responsible for the synthesis of mRNAs and most small nuclear RNAs, and consists of 12 subunits, the largest of which characteristically harbors a unique C-terminal domain (CTD). Transcriptional activity of RNA Pol II is highly regulated, in particular, by phosphorylation of serine residues in the CTD. Here, we have shown the presence of RNA Pol II CTD phosphoisoforms in porcine oocytes and preimplantation embryos. The distribution pattern as well as phosphorylation dynamics in germinal vesicles and during embryogenesis differed in developmental stages with these isoforms, indicating a role of RNA Pol II CTD phosphorylation at the serine residue in transcriptional activation during both oocyte growth and embryonic genome activation. We additionally examined the effects of the RNA Pol II inhibitor, ${\alpha}$-amanitin, on embryo development. Our results show that inhibition of polymerase, even at very early stages and for a short period of time, dramatically impaired blastocyst formation. These findings collectively suggest that the functionality of maternal RNA Pol II, and consequently, expression of early genes regulated by this enzyme are essential for proper embryo development.

• YAKHAK HOEJI
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• v.28 no.1
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• pp.35-48
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• 1984

우리나라 사람들에게는 유달리 높은 간염 발병률이 나타나고 있고 더우기 바이러스성 간염의 경우 풍토병 내지 전염병이라고 할 정도의 양상을 띠고 있다. 현재까지는 이러한 간질환에 적절한 치료약이 없는 점을 감안하여 저자들은 생약으로 부터 간질환에 유효한 성분을 분리하여 치료약으로 사용할 수 있도록 하기위하여 집중적인 연구를 지난 5년간 계속하여 왔다. 연구의 내용은 동서양의 고전및 연구보문을 조사하여 간보호 및 치료학으로 사용한 생약에 관한 문헌적 조사, 이들 생약중 채집 및 구입이 가능한 식물을 구하여 생약엑기스 제조, 이들 엑기스를 간염 동물 모델의 하나인 $CCl_{4}$로 유발시킨 간독성에 대한 보호작용의 검색, 보호작용을 나타내는 생약중에서 자원적 측면을 고려하여 국내에서 많이 생산되는 차전자(Plantago asiatica seeds)를 선택하였고, 차전자로 부터 간보호 작용을 나타내는 유효성분으로 iridoid 계열물질인 aucubin을 분리하였다. 그러나 aucubin이 차전자에 소량 밖에 없으므로 aucubin이 다량 함유된 식나무(Aucuba japonica)로 aucubin 추출자료생약을 바꾼후 aucubin의 간보호 작용을 간염 동물모델인, $CCl_{4}$ D-galactosamine 및 $\alpha$-amanitin등으로 유발시킨 간독성에 대한 보호작용을 보여 주었기 때문에, 이러한 간보호작용의 기전을 규명하는 연구를 진행하였고, 다음은 aucubin 자체의 급성 독성 및 기타 독성 유발여부를 밝히는 연구 등으로 요약 될 수 있다.

• Development and Reproduction
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• v.2 no.2
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• pp.197-203
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• 1998

DNA methylation seems to play an important regulatory role in gene expression and cell differentiation during postimplantation embryonic development. However, the significance of DNA methylation which is maintained by the DNA MTase during preimplantation embryonic development, is not fully understood. In order to study the role of DNA methylation in the preimplantation embryos, the expression of DNA MTase transcripts was monitored in the oocytes and preimplantation embryos. The mRNA of DNA MTase was detected in the oocytes and pleimplantation embryos. The relative mRNA levels of DNA MTase were high from the stages of GV-oocytes and pronuclear embryos, and thereafter decreased gradually. By the treatment of $\alpha$-amanitin, it was confirmed that the transcripts presented in pronuclear embryos was derived from the maternal genome. The presence of transcripts of DNA MTase in the oocytes and pronuclear embryos suggests that the maintenance of DNA methylation may be necessary and seems to play an important role in gene expression and cell differentiation during preimplantation embryonic develop-ment in mouse.

• Korean Journal of Pharmacognosy
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• v.14 no.3
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• pp.95-101
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• 1983

Aucubin, an iridoid glucoside which was previously reported to exhibit liver-protective activities against $CCl_4$ and ${\alpha}-amanitin$ induced liver damages, was subject to toxicological studies. To measure the lethal dose, the doses of 100mg/kg, 300mg/kg, 600mg/kg and 900mg/kg were administered intraperitoneally to experimental mice. No death was observed 24 hrs later, but serum GOT and alkaline phosphatase activities were deceased slightly at the doses of 300mg to 900mg/kg, and the triglyceride contents were slightly increased. To investigate acute toxicity of aucubin itself, multiple dosages(20 mg/kg, 40 mg/kg and 80 mg/kg for four times a week) were injected intraperitoneally into mice, then serum enzymes activities and chemistries were assayed; no significant change of the enzyme activities of alkaline phosphatase, GPT, GOT in the test groups were observed in comparison with those of the control group, and the contents of triglyceride, glucose, urea nitrogen and total proteins in the test group serums appeared to be almost same levels as those of the control group were. Histological examiation on liver biopsy samples indicated no gross changes between the control group and the test group were noted. Therefore, aucubin appears to be apparently low toxic substance and its minimum lethal dose in mouse seems to be more than 0.9 g.