• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.585-590
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• 2008

Human tropic Porcine Endogenous Retroviruses (PERVs) are the major concern in zoonosis for xenotransplantation because PERVs cannot be eliminated by specific pathogen-free breeding. Recently, a PERV A/C recombinant with PERV-C bearing PERV-A gp70 showed a higher infectivity (approximately 500-fold) to human cells than PERV-A. Additionally, the chance of recombination between PERVs and HERVs is frequently stated as another risk of xenografting. Overcoming zoonotic barriers in xenotransplantation is more complicated by recombination. To achieve successful xenotransplantation, studies on the recombination in PERVs are important. Here, we cloned and sequenced proviral PERV env sequences from pig gDNAs to analyze natural recombination. The envelope is the most important element in retroviruses as a pivotal determinant of host tropisms. As a result, a total of 164 PERV envelope genes were cloned from pigs (four conventional pigs and two miniature pigs). Distribution analysis and recombination analysis of PERVs were performed. Among them, five A/B recombinant clones were identified. Based on our analysis, we determined the minimum natural recombination frequency among PERVs to be 3%. Although a functional recombinant envelope clone was not found, our data evidently show that the recombination event among PERVs may occur naturally in pigs with a rather high possibility.

• 미생물학회지
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• 제52권1호
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• pp.116-119
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• 2016

텔로미어를 안정적으로 유지하는 것은 세포의 증식과 생존에 필수적이다. 비록 텔로미어 유지에는 telomerase가 가장 중요한 수단이지만 재조합도 텔로미어 유지를 위한 또 다른 중요한 과정으로 작용한다. 본 연구에서는 효모의 텔로미어 내부에 존재하는 $TG_{1-3}$ 반복서열을 이용하여 텔로미어 재조합을 관찰할 수 있는 유전학적 방법을 개발하였다. 관찰된 재조합 빈도는 내부 $TG_{1-3}$ 반복서열의 존재 여부에 영향을 받았으며, 생성된 $FOA^rCan^r$ 콜로니로부터 추출한 유전체 DNA를 사용하여 URA3와 CAN1 marker 근처 부위를 PCR 증폭한 결과, 각 콜로니들은 marker를 포함한 염색체 말단 부위가 결손 된 것으로 나타났다. 뿐만 아니라, 더 긴 내부 $TG_{1-3}$ 반복서열을 사용하였을 때 재조합 빈도는 더 증가하였다. 이러한 결과는 $FOA^rCan^r$ 콜로니 형성이 내부와 말단의 $TG_{1-3}$ 반복서열 사이의 재조합에 기인한다는 것을 의미한다.

• BMB Reports
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• 제53권2호
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• pp.112-117
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• 2020

A recent study suggested that methylation of ubiquitin-like with PHD and RING finger domain 1 (UHRF1) is regulated by SET7 and lysine-specific histone demethylase 1A (LSD1) and is essential for homologous recombination (HR). The study demonstrated that SET7-mediated methylation of UHRF1 promotes polyubiquitination of proliferating cell nuclear antigen (PCNA), inducing HR. However, studies on mediators that interact with and recruit UHRF1 to damaged lesions are needed to elucidate the mechanism of UHRF1 methylation-induced HR. Here, we identified that poly [ADP-ribose] polymerase 1 (PARP1) interacts with damage-induced methylated UHRF1 specifically and mediates UHRF1 to induce HR progression. Furthermore, cooperation of UHRF1-PARP1 is essential for cell viability, suggesting the importance of the interaction of UHRF1-PARP1 for damage tolerance in response to damage. Our data revealed that PARP1 mediates the HR mechanism, which is regulated by UHRF1 methylation. The data also indicated the significant role of PARP1 as a mediator of UHRF1 methylation-correlated HR pathway.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 1991년도 춘계학술발표대회 논문집
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• pp.82-96
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• 1991

To understand the mechanism of illegitimate recombination in mammalian cells, we have examined the recombination role of DNA topoisomerase II (Topo II ). We found that purified calf thymus Topo II mediates recombination between two phage $\lambda$ DNA molecules in an in vitro system. The enzyme mainly produced a linear monomer recombinant DNA that can be packaged in vitro. Novobiocin and anti-calf thymus Topo II antibody inhibit this ATP-dependent recombination. The recombinant molecules contain duplications or deletion, and most crossovers take place between nonhomologous sequences of $\lambda$ DNA, as judged by the sequences of recombination junctions. In order to study the effects of Topo II on illegitimate recombination in mammalian cells, we have developed a new shuttle vector, pNKl, which contains three bacterial genes, amp(APR), galK and neo($Km^R$). Using this system, we have shown that a Topo II inhibitor, VM26, stimulated deletion formation in pNK1 DNA in monkey COS1 cells. Both in vitro and in vivo results suggest that Topo II participates in illegitimate recombination in mammalian cells.

• Molecules and Cells
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• 제22권3호
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• pp.360-363
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• 2006

Human endogenous retroviruses (HERVs) contribute to various kinds of genomic instability via rearrangement and retrotransposition events. In the present study the formation of a new human-specific solo-LTR belonging to the HERV-H family (AP001667; chromosome 21q21) was detected by a comparative analysis of human chromosome 21 and chimpanzee chromosome 22. The solo-LTR was formed as a result of an equal homologous recombination excision event. Several evolutionary processes have occurred at this locus during primate evolution, indicating that mammalian-wide interspersed repeat (MIR) and full-length HERV-H elements integrated into hominoid genomes after the divergence of Old World monkeys and hominoids, and that the solo-LTR element was created by recombination excision of the HERV-H only in the human genome.

• 통합자연과학논문집
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• 제9권4호
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• pp.275-280
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• 2016

Intensity modulated photovoltage spectroscopy (IMVS) analysis of organic solar cells (OSCs) with a bulk-heterojunction (BHJ) film composed of P3HT and $PC_{61}BM$ was performed. The dynamic response of charge recombination by the post-annealing approach in $P3HT/PC_{61}BM$ BHJ solar cells characterized by IMVS demonstrated that post-annealing reduced the recombination of electron carriers in the device. The recombination times of $P3HT/PC_{61}BM$ BHJ solar cells post-annealed at room temperature, 80, 120, and $140^{\circ}C$ were 0.009, 0.020, 0.024, and 0.030 ms, respectively, at a short-circuit current of 0.18 mA. The results indicated that the IMVS analysis can be effectively used as powerful.

• 식물병연구
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• 제29권2호
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• pp.193-199
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• 2023

The apple stem grooving virus (ASGV) is one of the most harmful latent viruses infecting pear orchards worldwide. To examine the genetic diversity of ASGV in Korean pear orchards, the complete coat protein (CP) gene of five ASGV isolates collected from various regions were identified. The five Korean ASGV isolates showed 88-96% nucleotide identity with the 11 isolates worldwide occurring elsewhere in the world. Phylogenetic analysis of five isolates, as well as the previously sequenced isolates, indicated that the ASGV clusters had no correlation with the host or geographical regions of origin. Recombination analysis showed that one of the five Korean isolates is a recombinant, with a recombination site in the CP gene region (nt 532-708). This study is the first report of natural recombination within the CP gene of ASGV isolates from pears grown in Korea.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2000년도 제29회 국제학술심포지움 및 추계학술대회
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• pp.81-81
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• 2000

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2000년도 제29회 국제학술심포지움 및 추계학술대회
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• pp.82-82
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• 2000

• Journal of Microbiology
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• 제37권4호
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• pp.248-255
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• 1999

We have analyzed the MRE3/REC114 gene of Saccharomyces cerevisiae, previously detected in isolation of mutants defective in meiotic recombination. We cloned the MRE3/REC114 gene by complementation of the meiotic recombination defect and it has been mapped to chormosome XIII. The DNA sequence analysis revealed that the MRE3 gene is identical to the REC114 gene. The upstream region of the MRE3/REC114 gene contains a T_4C site, a URS (upstream repression sequence) and a TR (T-rich) box-like sequence, which reside upstream of many meiotic genes. Coincidentally, northern blot analysis indicated that the three sizes of MRE3/REC114 transcripts, 3.4, 1.4 and 1.2 kb, are induced in meiosis. A less abundant transcript of 1.4 kb is detected in both mitotic and meiotic cells, suggesting that it is needed in mitosis as well as meiosis. To examine the role of the MRE3/REC114 gene, we constructed mre3 disruption mutants. Strains carrying an insertion or null deletion of the MRE3/REC114 gene showed slow growth in nutrient medium and the doubling time of these cells increased approximately by 2-fond compared to the wild-type strain. Moreover, the deletion mutant (${\delta}$mre3) displayed no meiotically induced recombination and no viable spores. The mre3/rec114 spore lethality can be suppressed by spo13, a mutation that causes cells to bypass reductional division. The double-stranded breaks (DSBs) which are involved in initiation of meiotic recombination were not detected in the analysis of meiotic chromosomal DNA from the mre3/rec114 disruptant. From these results we suggest that the MRE3/REC114 gene product is essential in normal growth and in early meiotic stages involved in meiotic recombination.