α-Kleisin subunit of cohesin preserves the genome integrity of embryonic stem cells

Seobin Yoon,Eui-Hwan Choi,Seo Jung Park,김근필 생화학분자생물학회 2023 BMB Reports Vol.56 No.2

Cohesin is a ring-shaped protein complex that comprises theSMC1, SMC3, and α-kleisin proteins, STAG1/2/3 subunits, andauxiliary factors. Cohesin participates in chromatin remodeling,chromosome segregation, DNA replication, and gene expressionregulation during the cell cycle. Mitosis-specific α-kleisinfactor RAD21 and meiosis-specific α-kleisin factor REC8 are expressedin embryonic stem cells (ESCs) to maintain pluripotency. Here, we demonstrated that RAD21 and REC8 were involvedin maintaining genomic stability and modulating chromatinmodification in murine ESCs. When the kleisin subunits weredepleted, DNA repair genes were downregulated, thereby reducingcell viability and causing replication protein A (RPA) accumulation. This finding suggested that the repair of exposedsingle-stranded DNA was inefficient. Furthermore, the depletionof kleisin subunits induced DNA hypermethylation by upregulatingDNA methylation proteins. Thus, we proposed that thecohesin complex plays two distinct roles in chromatin remodelingand genomic integrity to ensure the maintenance of pluripotencyin ESCs.

아치 지지력 향상을 위한 기능형 인솔의 사용성 평가 연구

Misol Kim,Seobin Choi,Woojin Yoon,Donghyun Song,Eungee Kim,Gwanseob Shin 대한인간공학회 2018 대한인간공학회 학술대회논문집 Vol.2018 No.11

Cellular Dynamics of Rad51 and Rad54 in Response to Postreplicative Stress and DNA Damage in HeLa Cells

Choi, Eui-Hwan,Yoon, Seobin,Hahn, Yoonsoo,Kim, Keun P. Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.2

Homologous recombination (HR) is necessary for maintenance of genomic integrity and prevention of various mutations in tumor suppressor genes and proto-oncogenes. Rad51 and Rad54 are key HR factors that cope with replication stress and DNA breaks in eukaryotes. Rad51 binds to single-stranded DNA (ssDNA) to form the presynaptic filament that promotes a homology search and DNA strand exchange, and Rad54 stimulates the strand-pairing function of Rad51. Here, we studied the molecular dynamics of Rad51 and Rad54 during the cell cycle of HeLa cells. These cells constitutively express Rad51 and Rad54 throughout the entire cell cycle, and the formation of foci immediately increased in response to various types of DNA damage and replication stress, except for caffeine, which suppressed the Rad51-dependent HR pathway. Depletion of Rad51 caused severe defects in response to postreplicative stress. Accordingly, HeLa cells were arrested at the G2-M transition although a small amount of Rad51 was steadily maintained in HeLa cells. Our results suggest that cell cycle progression and proliferation of HeLa cells can be tightly controlled by the abundance of HR proteins, which are essential for the rapid response to postreplicative stress and DNA damage stress.

Elevated expression of exogenous RAD51 enhances the CRISPR/Cas9-mediated genome editing efficiency

Seo Jung Park,Seobin Yoon,Eui-Hwan Choi,Hana Hyeon,Kangseok Lee,김근필 생화학분자생물학회 2023 BMB Reports Vol.56 No.2

Genome editing using CRISPR-associated technology is widelyused to modify the genomes rapidly and efficiently on specificDNA double-strand breaks (DSBs) induced by Cas9 endonuclease. However, despite swift advance in Cas9 engineering,structural basis of Cas9-recognition and cleavage complex remainsunclear. Proper assembly of this complex correlates toeffective Cas9 activity, leading to high efficacy of genomeediting events. Here, we develop a CRISPR/Cas9-RAD51 plasmidconstitutively expressing RAD51, which can bind to singlestrandedDNA for DSB repair. We show that the efficiency ofCRISPR-mediated genome editing can be significantly improvedby expressing RAD51, responsible for DSB repair via homologousrecombination (HR), in both gene knock-out and knock-inprocesses. In cells with CRISPR/Cas9-RAD51 plasmid, expressionof the target genes (cohesin SMC3 and GAPDH) was reducedby more than 1.9-fold compared to the CRISPR/Cas9 plasmidfor knock-out of genes. Furthermore, CRISPR/Cas9-RAD51 enhancedthe knock-in efficiency of DsRed donor DNA. Thus, theCRISPR/Cas9-RAD51 system is useful for applications requiringprecise and efficient genome edits not accessible to HR-deficientcell genome editing and for developing CRISPR/Cas9-mediatedknockout technology.

Combined Ectopic Expression of Homologous Recombination Factors Promotes Embryonic Stem Cell Differentiation

Choi, Eui-Hwan,Yoon, Seobin,Kim, Keun P. Elsevier 2018 MOLECULAR THERAPY Vol.26 No.4

<P>Homologous recombination (HR), which ensures accurate DNA replication and strand-break repair, is necessary to preserve embryonic stem cell (ESC) self-renewal. However, little is known about how HR factors modulate ESC differentiation and replication stress-associated DNA breaks caused by unique cell-cycle progression. Here, we report that ESCs utilize Rad51-dependent HR to enhance viability and induce rapid proliferation through a replication-coupled pathway. In addition, ESC differentiation was shown to be enhanced by ectopic expression of a subset of recombinases. Abundant expression of HR proteins throughout the ESC cycle, but not during differentiation, facilitated immediate HR-mediated repair of single-stranded DNA (ssDNA) gaps incurred during S-phase, via amechanism that does not perturb cellular progression. Intriguingly, combined ectopic expression of two recombinases, Rad51 and Rad52, resulted in efficient ESC differentiation and diminished cell death, indicating that HR factors promote cellular differentiation by repairing global DNA breaks induced by chromatin remodeling signals. Collectively, these findings provide insight into the role of key HR factors in rapid DNA break repair following chromosome duplication during self-renewal and differentiation of ESCs.</P>

Software-Defined Radio 기반의 5G 모뎀에서 Cell Search 시간 감축을 위한 RSSI Sniffing 기법

김혜원(Hyewon Kim),한지윤(Ji Yoon Han),김빛나(BitNa Kim),정서빈(Seobin Jeong),김주엽(Juyeop Kim) 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.2

In this paper, we propose an RSSI sniffing function to reduce the time required for the cell search process. First we defined the RSSI measurement algorithm and then designed and implemented the protocol procedure between the PHY-RRC layers. In addition, to verify the performance, an experiment was conducted to find the ARFCN where the synchronization signal of the 5G commercial base station is located.

상품 사용기간에 따른 토픽별 사용자 평가의 변화 분석

안지예(Jiyea An),연진욱(Jinwook Yeon),윤서빈(Seobin Yoon),김남규(Namgyu Kim) 한국정보기술학회 2021 Proceedings of KIIT Conference Vol.2021 No.11

2016년 최저가 경쟁을 시작으로 국내 이커머스(E-commerce) 시장의 성장률은 꾸준히 상승했으며 경쟁 또한 치열해지고 있다. 특히 COVID-19로 인해 비대면 서비스들이 각광받기 시작하면서 온라인 쇼핑의 거래액도 급증하고 있다. 다양한 온라인 유통 채널들은 양질의 실구매 리뷰를 분석하여 소비자의 구매전환율을 높이고자, 다양한 유형의 리뷰를 남길 수 있는 기능을 제공하고 있다. 하지만 쇼핑 리뷰를 분석하는 연구들이 활발하게 이루어지고 있는 것에 비해 동일한 상품의 사용기간 차이에 따른 소비자 리뷰 변화를 분석한 연구는 상대적으로 부족하다. 이에 본 연구에서는 ‘네이버 쇼핑(스마트스토어)’의 ‘한 달 사용 리뷰’에 대해 토픽 모델링을 수행하여, 단기 사용 리뷰(Short-term Reviews)로부터 주요 토픽을 도출하고, 각 토픽에 해당하는 리뷰의 단기 평점과 장기 평점을 비교하고자 한다. 각 주제별 단기 평점과 장기 평점의 비교를 통해, 판매 전략 수립과 신상품 개발 및 개선에 도움이 되는 인사이트를 도출할 수 있을 것으로 기대한다. Starting with the bottom price competition in 2016, the growth rate of the domestic e-commerce market has been continuously increasing and competition in e-commerce market is also getting fiercer. Due to COVID-19, non-face-to-face services began to be in the spotlight and the transaction amount of online shopping is also increasing rapidly. So lots of online channels provide various services for acquiring various types of reviews in order to increase conversion rate by analyzing high-quality actual purchase reviews. However, while studies analyzing shopping reviews are being actively conducted, there are relative few studies on analyzing changes in consumer reviews according to the difference in usage period of the same product. Therefore, in this study, we perform topic modeling on the "monthly usage review" of "Naver Shopping (Smart Store)" to derive major topics from short-term reviews, and then compare the short-term and long-term star ratings of reviews for each topic. By comparing the short-term and long-term star ratings for each subject, we expect to be able to derive insights that help establish sales strategies and develop and improve new products.

SET7-mediated TIP60 methylation is essential for DNA double-strand break repair

( Song Hyun Kim ),( Junyoung Park ),( Jin Woo Park ),( Ja Young Hahm ),( Seobin Yoon ),( In Jun Hwang ),( Keun Pil Kim ),( Sang-beom Seo ) 생화학분자생물학회 2022 BMB Reports Vol.55 No.11

The repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) is crucial for maintaining genomic integrity and is involved in numerous fundamental biological processes. Post-translational modifications by proteins play an important role in regulating DNA repair. Here, we report that the methyltransferase SET7 regulates HR-mediated DSB repair by methylating TIP60, a histone acetyltransferase and tumor suppressor involved in gene expression and protein stability. We show that SET7 targets TIP60 for methylation at K137, which facilitates DSB repair by promoting HR and determines cell viability against DNA damage. Interestingly, TIP60 demethylation is catalyzed by LSD1, which affects HR efficiency. Taken together, our findings reveal the importance of TIP60 methylation status by SET7 and LSD1 in the DSB repair pathway. [BMB Reports 2022; 55(11): 541-546]