• Animal cells and systems
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• 제10권1호
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• pp.1-6
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• 2006

Previous studies showed that Cdc7 kinase of Schizosaccharomyces pombe phosphorylated the minichromosome maintenance (Mcm) complex efficiently in the presence of spMcm10 protein. The biochemical properties of the phosphorylated Mcm complexes were examined to understand the activation mechanism of the Mcm complex by Cdc7 kinase. The phosphorylation of Mcm complex in the presence of spMcm10 by Cdc7 kinase did not affect the stability of the Mcm complex containing all six subunits, and the changes in the sedimentation properties were not observed after the phosphorylation. The reconstitution of the Mcm complex using the purified proteins showed that the phosphorylation of Mcm2 proteins did not affect the interactions between Mcm proteins. The phosphorylation of the Mcm2-7 complex at the same condition also did not activate the other biochemical activities such as DNA helicase and single stranded (ss) DNA binding activities. On the other hand, spMcm10 protein that was used for the stimulation of Mcm phosphorylation showed single stranded DNA binding activity, and inhibited the DNA helicase activity of the Mcm4/6/7 complex. These inhibitory effects were reduced by the addition of Cdc7 kinase, suggesting that the phosphorylation by Cdc7 kinase decreased the interactions between spMcm10 and the Mcm complex. Taken together, these results suggested that the phosphorylation by Cdc7 kinase alone is not sufficient for the remodeling and the activation of the Mcm complex, and the additional factors or the phosphorylations might be required for the activation of the Mcm complex.

• BMB Reports
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• 제40권5호
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• pp.805-813
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• 2007

Although MCM2 is obviously important for the initiation of eukaryotic DNA replication, its role in $O_2$ dependent regulation of replicon initiation is poorly understood. In this report, I analysed the changes of MCM2 during the transition from hypoxically suppressed replicon initiation to the burst of initiation triggered by reoxygenation in T24 cells. A high level of chromatin bound and nucleosolic MCM2 was found under the hypoxic replicon arrest. In contrast low cytosolic MCM2 was noticed. Recovery of $O_2$ induced phosphorylation and diminution of chromatin bound MCM2, whereas cytosolic MCM2 increased. The level of chromatin bound Cdc7 did not change significantly upon reoxygenation. However, after reoxygenation, significant phosphorylation of Cdc7 and an increase of coimmunoprecipitation with its substrate (MCM2) were observed. This provides a hint that reoxygenation may promote the kinase activity of Cdc7. These changes might be the critical factors in $O_2$ dependent regulation of replicon initiation. Moreover, phosphorylation of Cdc7 by Cdk2 can be observed in vitro, but seems to fail to regulate the level of chromatin bound Cdc7 as well as the changes of MCM2 in response to reoxygenation of hypoxically suppressed cells.

• 혜화의학회지
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• 제14권1호
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• pp.201-211
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• 2005

Cdc2 kinase is a prototypical cyclin-dependent kinase critical for G2 to M phase cell cycle transition. Yet, its function in the nervous system is largely unknown. Here, we investigated possible role of Cdc2 in axonal regeneration using sciatic nerve system in rat. Cdc2 protein levels and activity were increased in the injured sciatic nerves 3 and 7 days after crush injury and then decreased to basal level 14 days later. Administration of Cdc2 kinase inhibitor roscovitine in vivo at the time of crush injury significantly inhibited axonal regeneration when regrowing axons were analyzed using retrograde tracers. Cdc2 protein levels in cultured Schwann cells which were prepared from sciatic nerves 7 days after crush injury were much higher compared with those from uninjured sciatic nerves, suggesting that Cdc2 protein expression was primarily induced in the Schwann cells. To further investigate Cdc2 function in Schwann cell, we examined changes in cultured Schwann cell proliferation and migration in culture system. Both the number of proliferating Schwann cells and the extent of neurite outgrowth from co-cultured DRG neurons were significantly decreased by Cdc2 inhibitor roscovitine treatment in DRG culture which was prepared from animals with sciatic nerve injury for 7 days. Also, Schwann cell migration in the injured sciatic nerve explant was significantly inhibited by roscovitine treatment. Taken together, the present data suggest that Cdc2 may be involved in peripheral nerve regeneration via Schwann cell proliferation and migration.

• 대한치위생과학회지
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• 제6권1호
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• pp.27-36
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• 2023

연구배경 및 목적: 본 연구의 목적은 미국질병관리센터(CDC) 치과감염관리 표준예방지침에 기준하여 감염관리 인식과 예방에 관한 인식을 알아보고자 하였다. 연구방법: CDC 치과감염관리 목록을 기준으로 'CDC 감염관리기준에 관한 표준 및 교육', 'CDC 감염관리 예방에 관한 사항', '연구대상자의 특성 및 감염관리 특성'에 관한 설문을 구성하였다. 총 222개의 설문을 빈도분석과 교차분석을 실시하여 분석에 활용하였다. 결과: 연구대상자의 특성은 대부분 대학병원이나 종합병원에 근무하고 있었으며 최근 1년이내 감염 예방 교육을 93.7%가 받은 것으로 나타났다. CDC 치과 감염관리 표준 및 교육 인식은 평균 77.2%로 이전 연구 결과와 비교해 더 높았다. 예방에 관한 인식은 평균 71.5%로 나타났으며 인증평가를 받은 그룹에서 통계적으로 유의한 차이로 예방에 관한 인식이 높았다(p<0.001). 결론: 본 연구 대상자는 감염관리 표준 및 교육 인식과 예방에 관한 인식이 이전연구 보다 높게 나타났다. 그러나 CDC 치과감염관리 표준예방지침에 비교하여 미흡한 수준이었다. 따라서 정부 부처와 관련 기관은 체계적인 감염관리 시스템을 구축하기 위한 노력이 필요하다.

• The Korean Journal of Physiology and Pharmacology
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• 제27권5호
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• pp.427-436
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• 2023

Mitotic arrest deficient 2 like 2 (Mad2L2, also known as Mad2B), the human homologue of the yeast Rev7 protein, is a regulatory subunit of DNA polymerase ζ that shares high sequence homology with Mad2, the mitotic checkpoint protein. Previously, we demonstrated the involvement of Mad2B in the cisplatin-induced DNA damage response. In this study, we extend our findings to show that Mad2B is recruited to sites of DNA damage in human cancer cells in response to cisplatin treatment. We found that in undamaged cells, Mad2B exists in a complex with Polζ-Rev1 and the APC/C subunit Cdc27. Following cisplatin-induced DNA damage, we observed an increase in the recruitment of Mad2B and Cdc20 (the activators of the APC/C), to the complex. The involvement of Mad2B-Cdc20-APC/C during DNA damage has not been reported before and suggests that the APC/C is activated following cisplatin-induced DNA damage. Using an in vitro ubiquitination assay, our data confirmed Mad2B-dependent activation of APC/C in cisplatin-treated cells. Mad2B may act as an accelerator for APC/C activation during DNA damage response. Our data strongly suggest a role for Mad2B-APC/C-Cdc20 in the ubiquitination of proteins involved in the DNA damage response.

• 생명과학회지
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• 제7권2호
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• pp.79-87
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• 1997

vibrio vulnificus의 균체내독소의 특성을 파악하여 비브리오 패혈증의 발병원인 구명을 위한 자료를 제공하고자 생균과 균체파쇄액의 치사독성과 내열성 및 혈관투과성항진작용을 실험한 결과는 다음과 같다. 1. 환자분리균(V.vulnificus CDC B3547)과 환경분리균(V.vulnificus B57)의 독력은 차이가 없었다. 2. V.vulnificus의 균수가 $10^{7}$/ml 이상일 때 강한 치사독력이 나타났다. 3. 균체파쇄액이 독성은 80$^{\circ}$C 20분에 완전히 불활성화 되었다. 4. 균체파쇄액은 용혈성은 없었으나 세포독성은 인정되었다. 5. V.vulnificus의 새앙주에 대한 주 치사독소는 균체 내에 존해했으나 LPS와 LPprotein complex는 기존의 방법으로 분리할 수 없었다.

• Journal of Korean Medical Science
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• 제33권47호
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• pp.303.1-303.10
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• 2018

Background: Cell division cycle 6 (CDC6) is an essential regulator of DNA replication and plays important roles in the activation and maintenance of the checkpoint mechanisms in the cell cycle. CDC6 has been associated with oncogenic activities in human cancers; however, the clinical significance of CDC6 in prostate cancer (PCa) remains unclear. Therefore, we investigated whether the CDC6 mRNA expression level is a diagnostic and prognostic marker in PCa. Methods: The study subjects included 121 PCa patients and 66 age-matched benign prostatic hyperplasia (BPH) patients. CDC6 expression was evaluated using real-time polymerase chain reaction and immunohistochemical (IH) staining, and then compared according to the clinicopathological characteristics of PCa. Results: CDC6 mRNA expression was significantly higher in PCa tissues than in BPH control tissues (P = 0.005). In addition, CDC6 expression was significantly higher in patients with elevated prostate-specific antigen (PSA) levels (> 20 ng/mL), a high Gleason score, and advanced stage than in those with low PSA levels, a low Gleason score, and earlier stage, respectively. Multivariate logistic regression analysis showed that high expression of CDC6 was significantly associated with advanced stage (${\geq}T3b$) (odds ratio [OR], 3.005; confidence interval [CI], 1.212-7.450; P = 0.018) and metastasis (OR, 4.192; CI, 1.079-16.286; P = 0.038). Intense IH staining for CDC6 was significantly associated with a high Gleason score and advanced tumor stage including lymph node metastasis stage (linear-by-linear association, P = 0.044 and P = 0.003, respectively). Conclusion: CDC6 expression is associated with aggressive clinicopathological characteristics in PCa. CDC6 may be a potential diagnostic and prognostic marker in PCa patients.

• BMB Reports
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• 제36권4호
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• pp.421-425
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• 2003

The serine/threonine protein kinase family is a large and diverse group of enzymes that are involved in the regulation of multiple cellular pathways. Elevated kinase activity has been implicated in many diseases and frequently targeted for the development of pharmacological inhibitors. Therefore, non-radioactive antibody-based kinase assays that allow high throughput screening of compound libraries have been developed. However, they require a generation of antibodies against the phosphorylated form of a specific substrate. We report here a time-resolved fluorescence assay platform that utilizes a commercially-available generic anti-phosphothreonine antibody and permits assaying kinases that are able to phosporylate threonin residues on protein substrates. Using this approach, we developed an assay for Cdc7/Dbf4 kinase activity, determined the $K_m$ for ATP, and identified rottlerin as a non-ATP competitive inhibitor of this enzyme.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제15권1호
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• pp.29-37
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• 2012

Purpose: To examine the prevalence of $Clostridium$ $difficile$ ($C.$ $difficile$) colonization (CDC) and potential neonatal determinants of CDC in hospitalized preterm infants. Methods: Fecal samples were serially collected within 72 h after birth and at 1, 2, and 4-6 weeks of age from preterm infants in the neonatal intensive care units (NICUs) of two different university hospitals. Total bacterial DNA was extracted from each fecal sample from 49 infants, and polymerase chain reaction (PCR) was performed with primers for the 16S gene of $C.$ $difficile$ and the toxin A and toxin B genes. The correlation between the results of $C.$ $difficile$ PCR assays and the clinical characteristics of the infants was analyzed. Results: The prevalence rates of CDC were 34.7, 37.2, 41.3, and 53.1% within 72 h after birth and at 1, 2, and 4.6 weeks of age, respectively. The toxin positivity rate was significantly higher in the infants with persistent CDC than in those with transient CDC (8/12 [66.7%] vs. 6/25 [24.5%] ($p$=0.001). Among the various neonatal factors, only the feeding method during the first week after birth was significantly associated with persistent CDC. Exclusive breast-milk feeding (EBMF) significantly decreased the risk of persistent CDC compared to formula or mixed feeding (adjusted odds ratio: 0.133, 95% confidence interval: 0.02-0.898, $p$=0.038). Conclusion: The prevalence of CDC increased with the duration of hospitalization in preterm infants in the NICU. EBMF during the first week after birth in hospitalized preterm infants may protect against persistent CDC.

• 한국임상수의학회지
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• 제22권4호
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• pp.322-327
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• 2005

보체의존성 세포독성반응(CDC)을 이용한 DLA class I교차 반응의 실험방법을 정립함으로써 개의 동종 신장이식 후 초기에 발생되는 초급성 거부반응을 억제하는데 응용하고자 븐 실험을 실시하였다. 체중(약 5kg)과 연령(약 1년령)이 유사한 잡종견을 대상으로 적혈구 교차 반응을 실시하여 상호 음성인 7마리를 실험에 사용하였다. 혈액형이 동일한 개체를 대상으로 CDC검사를 실시하였으며, Anti-dog serum, Hank's balanced salt solution (HBSS), 그리고 자가 혈청을 각각 양성 음성 그리고 자가 대조 혈청으로 이용하였다. Class I보체와 반응시킨 후 에오신으로 염색하여 고정한 다음 위상차 현미경 100배율에서 조사하였다. 국제 Cytotoxicity scoring system에 의하려 죽은 세포가 $20\%$ 이상이면 양성으로 평가하였다. CDC 결과 동일 혈액형 군에서 상호 음성이 나온 경우를 대상으로 상호 동종이식을 실시하여 초급성 거부반응의 발생 정도를 평가하였다. 혈액형이 1.2 B인 4두 중 1두는 자가항체를 가지고 있었다. CDC 결과 동일 혈액형 군에서 각각 1쌍이 상호 음성을 나타내었고, 혈액형이 다른 1쌍에서도 상호 음성이 관찰되었다. 혈액형이 동일하고 CDC음성인 2쌍 4두를 대상으로 상호 신장 이식을 한 결과 4마리 모두 초급성 거부반응이 나타나지 않았다. 이 실험에서 확립한 DLA교차 방법은 동종 이식에서 초급성 거부반응을 억제하는데 효과적인 방법이며, 향후 개의 동종 장기 이식에서 조직적합성 평가를 위해 응용될 수 있을 것이라 사료된다.