• 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.

• 농업과학연구
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• 제38권1호
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• pp.71-77
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• 2011

Pigs have anatomically and physiologically very similar to human and because of this, pigs are the possible xenotransplantation donors for human organs. PERVs (Porcine Endogenous Retroviruses) are known to be one of the possible obstacles for using porcine organs regardless of the immunological barriers. In order to understand the expression patterns of PERVs in Korean native pigs, we investigated PERV expressions in porcine liver, heart, spleen, and lung samples. After RNA extraction, two types of specific PERV envelope genes (ENV-A and ENV-B) were amplified using specific primers by RT-PCR. The results indicated that the variable PERV expressions were observed in inconsistent patterns among animals and tissues. The PERV expressions were verified with semi-quantitative real-time PCR with three replicates. Even though, these results confirm the previous findings that the PERVs were differentially expressed between animals and tissues. These results also give some valuable information for xenotransplantation when using the Korean native pigs as the organ donor.

• Journal of Animal Science and Technology
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• 제46권3호
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• pp.307-314
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• 2004

돼지를 이용한 이종간 장기 이식은 차세대 장기 공급 부족 문제를 해결해 줄 수 있는 가능성을 제공해준다. 그러나 돼지 장기를 이용한 이종간 장기 이식은 면역학적인 문제 외에도 가축 유래 전염성 병원균에 대한 안전성 문제가 심각하게 고려되어지고 있다. 대부분의 외인성 병원균은 무균 사육환경을 통해 제어되는 반면 내인성 레트로 바이러스(Endogenous Retrovirus, PERVs)는 germ line을 통해 전파됨으로 사육 조건으로 해결할 수는 없다. 본 연구는 이종간 장기 이식용 무균 돼지 생산시 가장 문제가 되는 PERVs에 대한 분포를 알아보고자 국내 돼지(Landrace, Berkshire, Yorkshire, Duroc)의 genome 내 PERVs 분포와 유전자 염기 서열을 비교하였다. 모든 공시 돼지(20두)의 genomic DNA로부터 PCR을 이용하여 PERV A/B/C와 PERV-E의 존재를 확인하였다. pol 유전자 일부 염기 서열 분석 결과 같은 품종내 개체간 또는 품종간 상동성이 99.1과 98.8%로 매우 높게 나왔다. 본 연구의 결과 모든 국내 돼지 유전자내에 PERV A/B/C와 PERV E가 provirus 형태로 많이 존재하며 바이러스간의 높은 상동성은 바이러스 제어에 많은 잇점으로 작용하리라 사료되며 아직 밝혀지지 않은 내인성바이러스에 대한 연구가 요구되어진다. 그러므로 본 연구의 자료는 이종간 장기 이식용 무균돼지 생산 시 PERVs 를 제어하기 위한 기초 자료로 활용될 수 있을 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제20권4호
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• pp.461-465
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• 2007

Porcine Endogenous Retroviruses (PERVs) are a major concern in relation to xenotransplantation. Previous research indicated that PERVs are present at about 50 copies in the pig genome and their chromosomal insertion sites are different among pig breeds. We examined nine Korean native pigs and seven Asian Wild Boars for the presence of a PERV-A at SSC 1q2.4 and a PERV-B at SSC 7p1.1-2 previously reported in a Large White pig. The PERV-B at locus 7p1.1-2 displayed insertional variability in Korean native pigs and Asian Wild Boars. Using the primers for the PERV-A at 1q2.4 from Large White pig, we only can amplify an unclassified 798 bp sequence, which showed insertional variability only in Korean native pigs. This study indicates that there are differences within and between Asian and European pigs in PERV insertions and suggests that selection could generate PERV-free lines of pigs more suitable for xenotransplantation.

• 농업과학연구
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• 제36권2호
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• pp.159-165
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• 2009

본 연구는 현재까지 발표된 돼지의 genomic sequence 정보를 이용하여 PERV들의 정확한 삽입 위치를 파악하고 그들의 특성을 분석하고자 실시하였으며 총 2.7 Gb인 돼지 genome 염기서열 중 4.2%인 114 Mb의 염기서열에서 PERV sequence를 확인한 결과 총 8개의 PERV sequence를 확인할 수 있었다. 확인된 PERV sequence중 7개는 유전자내에 deletion이 확인되었으며 나머지 한 개의 PERV도 gag와 env 유전자에 stop codon이 확인되어 정상적인 PERV로 발현되지 않을 것으로 추정되었다. 본 연구는 돼지를 이용한 이종장기이식과 관련하여 PERV를 제어하기 위한 중요한 기초 연구 자료를 제공할 것으로 사료된다.

• Journal of Animal Science and Technology
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• 제47권2호
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• pp.177-186
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• 2005

Xenotransplantation may help to overcome the critical shortage of human tissues and organs for human transplantation, Swine represents an ideal source of such organs owing to their anatomical and physiological similarities to human besides their plentiful supply, However, the use of organs across the species barrier may be associated with the risk of transmission of pathogens, specially porcine endogenous retroviruses (PERVs).• Although most of these potential pathogens could be eliminated by pathogen-free breeding, PERVs are not eliminated by this treatment. PERVs are integrated into the genome of all pigs and produced by normal pig cells and infect human cells. They belong to gamma retroviruses and are of three classes viruses: A, B and C. In the present study, PCR based cloning was performed with chromosomal DNA extracted from pigs from domestic pigs in Korea. Amplified PCR fragments of about 1.5 Kb, covering the partial env gene, were cloned into pCR2.l-TOPO vectors and sequenced. A total of 91 env clones were obtained from domestic pigs, Berkshire, Duroc, Landrace and Yorkshire in Korea. Phylogenetic analysis of these genes revealed the presence of only PERV class A and B in the proportion of 58 % and 42 %, respectively. Among these, 28 clones had the correct open reading frame: 18 clones in class A and 10 clones in class B. Since both these PERV classes are polytropic and have the capacity to infect human cells, our data suggest that proviral PERVs have the potential to generate infectious viruses during or after xenotransplantation in human.

• Asian-Australasian Journal of Animal Sciences
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• 제14권10호
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• pp.1497-1504
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• 2001

There is emerging interest in using xenotransplantation of porcine cells, tissues and organs for treatment of human illness. This article reviews the current status of xenotransplantation, with particular emphasis on the physiological and immunological barriers to xenotransplantation and genetic manipulations to overcome xenograft rejection. Preliminary success in xenotransplantation therapy for human Parkinson's disease using porcine foetal brain cells is described. Finally the zoonotic dangers of porcine xenotransplantation, most particularly porcine endogenous retroviruses (PERVs), are discussed.

• Molecules and Cells
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• 제24권1호
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• pp.148-151
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• 2007

Porcine endogenous retroviruses (PERVs) in the pig genome represent a potential risk of infection in pig-to-human transplantation and are transmitted vertically. The solitary long terminal repeat (LTR) elements of the PERVs affect the replication properties of the individual viruses via their repeat sequences and by encoding a set of specific transcription factors. We examined the promoter activities of solitary LTR elements belonging to the PERV-A and -B families of the Korean domestic pig (KDP) using luciferase reporters. Three of the LTR structures (of PERV-A5-KDP, PERV-A7-KDP, PERV-A8-KDP) had different promoter activities in human HCT116 cells and monkey Cos7 cells, and potential negatively and positively acting regions affecting transcription were identified by deletion analysis. These data suggest that specific sequences in the U3 region of a given LTR element can affect the activities of promoter or enhancer elements in the PERV.

• Journal of Microbiology and Biotechnology
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• 제24권4호
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• pp.577-583
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• 2014

Three major classes of retroviral restriction factors (APOBEC3G, Tetherin, and TRIM5${\alpha}$) have been identified in mammals. Restriction factors are cellular proteins that are able to limit viral replication by targeting specific steps of the viral life cycle. To evaluate which restriction factor is the most effective to inhibit the replication of porcine endogenous retroviruses (PERVs), the antiviral activity of each restriction factor was compared. In pseudotype assay, the antiviral activity of human tetherin against PERV pseudotype was slightly weaker than that of human APOBEC3G (hA3G). A combination of tetherin and hA3G was more potent than each individual restriction factor. We questioned whether a combination of tetherin and hA3G could also inhibit the spreading replication of PERV. In agreement with the pseudotype assay, two restriction factors inhibit infectious PERV replication in a spreading infection. In this study, hA3G could strongly inhibit the replication of PERV, but tetherin modestly restricted it. Based on these results, we concluded that a combination of tetherin and hA3G is the most effective way to restrict PERV. A combination of different restriction factors will encourage the development of a new approach to treat retroviral disease.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2004년도 제4회 발생공학 국제심포지움 및 학술대회
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• pp.96-96
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• 2004