Function of the pentose phosphate pathway and its key enzyme, transketolase, in the regulation of the meiotic cell cycle in oocytes / 대한생식의학회지

OBJECTIVE: Previously, we identified that transketolase (Tkt), an important enzyme in the pentose phosphate pathway, is highly expressed at 2 hours of spontaneous maturation in oocytes. Therefore, this study was performed to determine the function of Tkt in meiotic cell cycle regulation, especially at the point of germinal vesicle breakdown (GVBD). METHODS: We evaluated the loss-of-function of Tkt by microinjecting Tkt double-stranded RNAs (dsRNAs) into germinal vesicle-stage oocytes, and the oocytes were cultured in vitro to evaluate phenotypic changes during oocyte maturation. In addition to maturation rates, meiotic spindle and chromosome rearrangements, and changes in expression of other enzymes in the pentose phosphate pathway were determined after Tkt RNA interference (RNAi). RESULTS: Despite the complete and specific knockdown of Tkt expression, GVBD occurred and meiosis was arrested at the metaphase I (MI) stage. The arrested oocytes exhibited spindle loss, chromosomal aggregation, and declined maturation promoting factor and mitogen-activated protein kinase activities. The modified expression of two enzymes in the pentose phosphate pathway, Prps1 and Rbks, after Tkt RNAi and decreased maturation rates were amended when ribose-5-phosphate was supplemented in the culture medium, suggesting that the Tkt and pentose phosphate pathway are important for the maturation process. CONCLUSION: We concluded that Tkt and its associated pentose phosphate pathway play an important role in the MI-MII transition of the oocytes' meiotic cell cycle, but not in the process of GVBD.

Lin28 regulates the expression of neuropeptide Y receptors and oocyte-specific homeobox genes in mouse embryonic stem cells / 대한생식의학회지

OBJECTIVE: Lin28 has been known to control the proliferation and pluripotency of embryonic stem cells. The purpose of this study was to determine the downstream effectors of Lin28 in mouse embryonic stem cells (mESCs) by RNA interference and microarray analysis. METHODS: The control siRNA and Lin28 siRNA (Dharmacon) were transfected into mESCs. Total RNA was prepared from each type of transfected mESC and subjected to reverse transcription-polymerase chain reaction (RT-PCR) analysis to confirm the downregulation of Lin28. The RNAs were labeled and hybridized with an Affymetrix Gene-Chip Mouse Genome 430 2.0 array. The data analysis was accomplished by GenPlex 3.0 software. The expression levels of selected genes were confirmed by quantitative real-time RT-PCR. RESULTS: According to the statistical analysis of the cDNA microarray, a total of 500 genes were altered in Lin28-downregulated mESCs (up-regulated, 384; down-regulated, 116). After differentially expressed gene filtering, 31 genes were selected as candidate genes regulated by Lin28 downregulation. Among them, neuropeptide Y5 receptor and oocyte-specific homeobox 5 genes were significantly upregulated in Lin28-downregulated mESCs. We also showed that the families of neuropeptide Y receptor (Npyr) and oocyte-specific homeobox (Obox) genes were upregulated by downregulation of Lin28. CONCLUSION: Based on the results of this study, we suggest that Lin28 controls the characteristics of mESCs through the regulation of effectors such as the Npyr and Obox families.

Mechanisms of Granulosa Cell Transition from Proliferation to Differentiation During the Ovulatory Process in Rodents: Role of Interferon-alpha System / 대한불임학회지

No abstract available.

A Case of Anti-Thrombin III Deficiency Discovered by Myocardial Infarction

Anti-thrombin III deficiency is known as a disease of autosomal dominant trait and relatively common, but in Korea, exact incidence and mortality is not known, In general, Anti-thrombin III deficiency is expressed to venous thromboembolism like deep vein thrombosis or pulmonary embolism. But, arterial embolism is very rare. We experienced a case of Antithrombin III deficiency expressed as myocardial infarction of inferior wall by huge thrombosis in the mid and distal right coronary artery.