• Biomolecules & Therapeutics
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• 제25권4호
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• pp.396-403
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• 2017

Under normal, non-stressed conditions, intracellular p53 is continually ubiquitinated by MDM2 and targeted for degradation. However, in response to severe genotoxic stress, p53 protein levels are markedly increased and apoptotic cell death is triggered. Inhibiting the ubiquitination of p53 under conditions where DNA damage has occurred is therefore crucial for preventing the development of cancer, because if cells with severely damaged genomes are not removed from the population, uncontrolled growth can result. However, questions remain about the cellular mechanisms underlying the regulation of p53 stability. In this study, we show that p53-inducible gene 3 (PIG3), which is a transcriptional target of p53, regulates p53 stability. Overexpression of PIG3 stabilized both endogenous and transfected wild-type p53, whereas a knockdown of PIG3 lead to a reduction in both endogenous and UV-induced p53 levels in p53-proficient human cancer cells. Using both in vivo and in vitro ubiquitination assays, we found that PIG3 suppressed both ubiquitination- and MDM2-dependent proteasomal degradation of p53. Notably, we demonstrate that PIG3 interacts directly with MDM2 and promoted MDM2 ubiquitination. Moreover, elimination of endogenous PIG3 in p53-proficient HCT116 cells decreased p53 phosphorylation in response to UV irradiation. These results suggest an important role for PIG3 in regulating intracellular p53 levels through the inhibition of p53 ubiquitination.

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2001년도 Korean Environmental Mutagen Society
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• pp.9-9
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• 2001

• Molecules and Cells
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• 제40권5호
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• pp.339-345
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• 2017

Retroviral and lentiviral vectors are mostly pseudotyped and often purified and concentrated via ultracentrifugation. In this study, we quantified and compared the stabilities of retroviral [murine leukemia virus (MLV)-based] and lentiviral [human immunodeficiency virus (HIV)-1-based] vectors pseudotyped with relatively mechanically stable envelope proteins, vesicular stomatitis virus glycoproteins (VSVGs), and the influenza virus WSN strain envelope proteins against ultracentrifugation. Lentiviral genomic and functional particles were more stable than the corresponding retroviral particles against ultracentrifugation when pseudotyped with VSVGs. However, both retroviral and lentiviral particles were unstable when pseudotyped with the influenza virus WSN strain envelope proteins. Therefore, the stabilities of pseudotyped retroviral and lentiviral vectors against ultracentrifugation process are a function of not only the type of envelope proteins, but also the type of viral internal core (MLV or HIV-1 core). In addition, the fraction of functional viral particles among genomic viral particles greatly varied at times during packaging, depending on the type of envelope proteins used for pseudotyping and the viral internal core.

• Journal of Genetic Medicine
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• 제13권1호
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• pp.1-13
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• 2016

Although some mutations are beneficial and are the driving force behind evolution, it is important to maintain DNA integrity and stability because it contains genetic information. However, in the oxygen-rich environment we live in, the DNA molecule is under constant threat from endogenous or exogenous insults. DNA damage could trigger the DNA damage response (DDR), which involves DNA repair, the regulation of cell cycle checkpoints, and the induction of programmed cell death or senescence. Dysregulation of these physiological responses to DNA damage causes developmental defects, neurological defects, premature aging, infertility, immune system defects, and tumors in humans. Some human syndromes are characterized by unique neurological phenotypes including microcephaly, mental retardation, ataxia, neurodegeneration, and neuropathy, suggesting a direct link between genomic instability resulting from defective DDR and neuropathology. In this review, rare human genetic disorders related to abnormal DDR and damage repair with neural defects will be discussed.

• Molecules and Cells
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• 제46권1호
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• pp.57-64
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• 2023

In eukaryotic cells, a key RNA processing step to generate mature mRNA is the coupled reaction for cleavage and polyadenylation (CPA) at the 3' end of individual transcripts. Many transcripts are alternatively polyadenylated (APA) to produce mRNAs with different 3' ends that may either alter protein coding sequence (CDS-APA) or create different lengths of 3'UTR (tandem-APA). As the CPA reaction is intimately associated with transcriptional termination, it has been widely assumed that APA is regulated cotranscriptionally. Isoforms terminated at different regions may have distinct RNA stability under different conditions, thus altering the ratio of APA isoforms. Such differential impacts on different isoforms have been considered as post-transcriptional APA, but strictly speaking, this can only be considered "apparent" APA, as the choice is not made during the CPA reaction. Interestingly, a recent study reveals sequential APA as a new mechanism for post-transcriptional APA. This minireview will focus on this new mechanism to provide insights into various documented regulatory paradigms.

• Journal of Oral Medicine and Pain
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• 제31권1호
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• pp.1-16
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• 2006

최근 진단분야에 있어서의 가장 획기적인 진보로는 향상된 진단 술식의 민감도와 특이도를 들 수 있으며 이는 다양한 면역 화학물질과 분자생물학적 시약의 활용도가 증가되고 이와 더불어 진단용 기구의 수준 향상으로 가능해진 미세 술식의 발달에 따른 결과이다. 이러한 기술의 발전은 임상검사용 검체 뿐만 아니라 DNA의 공급원으로서의 타액의 진단학적 가치를 고려하게 되었다. 본 연구는 인체의 타액에서 genomic DNA를 분리하고 이를 혈액 및 협점막 swab에서 분리한 genomic DNA와 비교 검토해 봄으로써 타액 검체의 진단학적 활용도를 살펴보고, 타액 검체의 다양한 보관 과정이 genomic DNA의 분리에 미치는 영향을 살펴보고자 시행되었으며, 또한 분리된 genomic DNA의 안정도를 살펴보고자 중합효소 연쇄반응 분석법을 이용하여 $\beta$-globin 유전자의 증폭을 시행하였다. 10명의 피검자(평균 나이: $29.9{\pm}9.8$ 세)를 대상으로 혈액, 비자극성, 자극성 전타액 및 협점막 swab을 채취한 후 이로부터 genomic DNA를 분리하였다. 여러 다양한 보관조건이 genomic DNA에 미치는 영향을 알아보기 위하여 건강한 20명의 피검자(평균 나이: $32.3{\pm}6.6$ 세)를 대상으로 자극성 전타액을 채취하여 실온, $4^{\circ}C$, $-20^{\circ}C$, $-70^{\circ}C$, 자연 건조 및 동결 건조 상태에서 1, 3, 5 개월 동안 보관한 후 genomic DNA를 분리, 조사하였으며, 분리된 genomic DNA의 안정도를 살펴보고자 중합효소 연쇄반응 분석법을 이용하여 989-bp의 $\beta$-globin 유전자를 증폭한 후 전기영동 검사를 시행하여 다음과 같은 결론을 얻었다. 1. 타액으로부터 분리한 genomic DNA의 농도는 혈액의 경우에 비하여 유의하게 낮았으며(p<0.05), 타액군 간에는 유의한 차이가 없었다. 자극성 전타액과 이를 동결 건조한 검체에서 분리한 genomic DNA의 순도는 혈액의 경우에 비하여 유의하게 높았으며(p<0.05), 협점막 swab으로부터 분리한 genomic DNA 의 순도는 타액의 경우에 비하여 유의하게 낮게 나타났다(p<0.05). 2. 실온에서 보관한 타액 검체로부터 분리한 genomic DNA의 농도는 1 개월 후부터 점차적으로 감소되었으며, 3 개월과 5개월 동안 보관한 타액 검체에서는 유의하게 감소되었다(각각 p<0.05, p<0.01). DNA의 순도 또한 점차적으로 감소되어 3 개월과 5 개월 동안 보관한 타액 DNA의 순도는 신선한 타액과 1 개월 동안 보관된 타액 검체의 순도보다 낮게 나타났다(p<0.05). 3. 타액 검체를 $4^{\circ}C$와 $-20^{\circ}C$에서 보관한 후 분리한 genomic DNA의 농도는 3 개월의 보관 기간 동안 유의한 변화가 없었으나, 보관 기간 5 개월 후의 검체에서는 유의하게 감소되었다(p<0.05). 4. 타액을 $-70^{\circ}C$에서 보관한 검체와 동결 건조한 후 보관한 검체로부터 분리한 genomic DNA의 농도는 보관 기간에 따른 유의한 차이를 보이지 않았으나, 보관 후 5 개월 후의 검체에서는 DNA의 농도가 감소되는 경향을 보였다. 5. 타액을 자연 건조한 후 즉시 genomic DNA를 분리한 결과, 신선한 타액에 비하여 약 60%의 DNA를 얻을 수 있었다. 자연 건조한 후에 실온에서 보관한 타액 검체로부터 분리한 genomic DNA 농도는 보관 2 주 만에 급격하게 감소되었다(p<0.05). 6. 중합효소 연쇄반응 방법을 이용한 $\beta$-globin 유전자의 증폭은 동결 건조한 후 보관한 타액의 경우 보관 기간 5 개월까지의 모든 검체에서 가능하였으며, 보관 기간 1 개월을 기준으로 보았을 때 $-20^{\circ}C$와 $-70^{\circ}C$에서 보관한 타액의 경우 모든 검체에서, $4^{\circ}C$에서 보관한 타액의 경우 일부분의 검체에서만 증폭이 가능하였고, 실온에서 보관한 타액과 자연 건조 후 실온에서 보관한 타액의 경우는 증폭이 이루어지지 않았다.

• Molecules and Cells
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• 제38권9호
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• pp.750-758
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• 2015

Genomic instability and altered metabolism are key features of most cancers. Recent studies suggest that metabolic reprogramming is part of a systematic response to cellular DNA damage. Thus, defining the molecules that fine-tune metabolism in response to DNA damage will enhance our understanding of molecular mechanisms of tumorigenesis and have profound implications for the development of strategies for cancer therapy. Sirtuins have been established as critical regulators in cellular homeostasis and physiology. Here, we review the emerging data revealing a pivotal function of sirtuins in genome maintenance and cell metabolism, and highlight current advances about the phenotypic consequences of defects in these critical regulators in tumorigenesis. While many questions should be addressed about the regulation and context-dependent functions of sirtuins, it appears clear that sirtuins may provide a promising, exciting new avenue for cancer therapy.

• BMB Reports
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• 제56권2호
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• pp.108-113
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• 2023

Cohesin is a ring-shaped protein complex that comprises the SMC1, SMC3, and α-kleisin proteins, STAG1/2/3 subunits, and auxiliary factors. Cohesin participates in chromatin remodeling, chromosome segregation, DNA replication, and gene expression regulation during the cell cycle. Mitosis-specific α-kleisin factor RAD21 and meiosis-specific α-kleisin factor REC8 are expressed in embryonic stem cells (ESCs) to maintain pluripotency. Here, we demonstrated that RAD21 and REC8 were involved in maintaining genomic stability and modulating chromatin modification in murine ESCs. When the kleisin subunits were depleted, DNA repair genes were downregulated, thereby reducing cell viability and causing replication protein A (RPA) accumulation. This finding suggested that the repair of exposed single-stranded DNA was inefficient. Furthermore, the depletion of kleisin subunits induced DNA hypermethylation by upregulating DNA methylation proteins. Thus, we proposed that the cohesin complex plays two distinct roles in chromatin remodeling and genomic integrity to ensure the maintenance of pluripotency in ESCs.

• BMB Reports
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• 제51권10호
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• pp.500-507
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• 2018

Cell reprogramming has been considered a powerful technique in the regenerative medicine field. In addition to diverse its strengths, cell reprogramming technology also has several drawbacks generated during the process of reprogramming. Telomere shortening caused by the cell reprogramming process impedes the efficiency of cell reprogramming. Transcription factors used for reprogramming alter genomic contents and result in genetic mutations. Additionally, defective mitochondria functioning such as excessive mitochondrial fission leads to the limitation of pluripotency and ultimately reduces the efficiency of reprogramming. These problems including genomic instability and impaired mitochondrial dynamics should be resolved to apply cell reprograming in clinical research and to address efficiency and safety concerns. Sirtuin (NAD+-dependent histone deacetylase) has been known to control the chromatin state of the telomere and influence mitochondria function in cells. Recently, several studies reported that Sirtuins could control for genomic instability in cell reprogramming. Here, we review recent findings regarding the role of Sirtuins in cell reprogramming. And we propose that the manipulation of Sirtuins may improve defects that result from the steps of cell reprogramming.

• Journal of Microbiology and Biotechnology
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• 제26권3호
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• pp.511-520
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• 2016

The most energy-demanding step of wastewater treatment is the aeration-dependent elimination of organic carbon. Microbial fuel cells (MFCs) offer an alternative strategy in which carbon elimination is conducted by anaerobic microorganisms that transport respiratory electrons originating from carbon oxidation to an anode. Hence, chemical energy is directly transformed into electrical energy. In this study, the use and stability of barcode-containing exoelectrogenic model biofilms under non-axenic wastewater treatment conditions are described. Genomic barcodes were integrated in Shewanella oneidensis, Geobacter sulfurreducens, and G. metallireducens. These barcodes are unique for each strain and allow distinction between those cells and naturally occurring wild types as well as quantification of the amount of cells in a biofilm via multiplex qPCR. MFCs were pre-incubated with these three strains, and after 6 days the anodes were transferred into MFCs containing synthetic wastewater with 1% wastewater sludge. Over time, the system stabilized and the coulomb efficiency was constant. Overall, the initial synthetic biofilm community represented half of the anodic population at the end of the experimental timeline. The part of the community that contained a barcode was dominated by G. sulfurreducens cells (61.5%), while S. oneidensis and G. metallireducens cells comprised 10.5% and 17.9%, respectively. To the best of our knowledge, this is the first study to describe the stability of a synthetic exoelectrogenic consortium under non-axenic conditions. The observed stability offers new possibilities for the application of synthetic biofilms and synthetically engineered organisms fed with non-sterile waste streams.