• 대한바이러스학회지
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• 제30권2호
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• pp.131-139
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• 2000

Bovine leukemia virus (BLV) is an etiological agent of chronic diseases in cows worldwide. The BLV is one of retroviruses that contain a multi-functional enzyme, reverse transcriptase produced from the pol gene in its genome. We have sequenced some regions in the pol gene of BLV proviruses found in the Southern province of Korea from samples that turned out to be BL V positives by a PCR analysis. On the 5' side of the BLV pol gene (polymerase region), it was found that there were four leucines located at every 7 amino acids. They can form a leucine zipper motif that was not same as the pol gene of Japanese BLV isolate. The sequencing result of the proviral pol gene in Korean-type BLV also revealed some mutations leading to amino acid changes such as $CCT(Pro){\to}CTC(Leu)$, $AAT(Asn){\to}AAA(Lys)$, and non-sensible variations i.e., $TCT(Ser){\to}TCC(Ser)$, $ATT(Ile){\to}ATC(I1e)$ and $ACG(Thr){\to}ACA(Thr)$. On the 3' side of the pol gene (integrase region), some nucleotide sequences were mutated and led to amino acid changes. Among them, a mutation, $GAA(Glu){\to}GAC(Asp)$ occurred in many Korean-type BLV proviruses was very interesting because the amino acid was regarded as one of the most conserved amino acids in the retroviral integrase. It was also notable that the mutation on any leucine residue did not occur, in spite of its frequent appearance.

• 미생물학회지
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• 제30권2호
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• pp.134-140
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• 1992

Teh $polA^{+}$ gene can be transducted in a multicopy mini-Mu plasmid, but not cloned because the product of this gene is lethal when overproduced. Although, we obtained one surviving cell, in which the ColEl-derived mini-Mu plasmid suffered a spontaneous deletion exactly at the region where the $polA^{+}$ gene was cloned. The $PolA^{+}$ unstream flanking sequence containing the promoter and pribnow-box was delected in vivo ; consequently this gene is not able to be expressed.

• Journal of Ginseng Research
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• 제43권4호
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• pp.684-691
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• 2019

Background: We have reported that defective nef and gag genes are induced in HIV-1-infected patients treated with Korean Red Ginseng (KRG). Methods: To investigate whether KRG treatment and highly active antiretroviral therapy (HAART) affect genetic defects in the pol gene, we amplified and sequenced a partial pol gene (p-pol) containing the integrase portion (1.2 kb) by nested PCR with sequential peripheral blood mononuclear cells over 20 years and compared it with those patients at baseline, in control patients, those taking ginseng-based combination therapy (GCT; KRG plus combinational antiretroviral therapy) and HAART alone. We also compared our findings to look for the full-length pol gene (pol) (3.0-kb) Results: Twenty-patients infected with subtype B were treated with KRG for $116{\pm}58months$ in the absence of HAART. Internal deletion in the pol gene (${\Delta}pol$) was significantly higher in the KRG group (11.9%) than in the control group and at baseline; its detection was significantly inhibited during GCT as much as during HAART. In addition, the ${\Delta}pol$ in p-pol significantly depended on the duration of KRG treatment. In pol, the proportion of ${\Delta}pol$ was significantly higher in the KRG group (38.7%) than in the control group, and it was significantly inhibited during GCT and HAART. In contrast, the proportion of stop codon appeared not to be affected by KRG treatment. The PCR success rate was significantly decreased with longer GCT. Conclusion: The proportion of ${\Delta}pol$ depends on template size as well as KRG treatment. HAART decreases the detection of ${\Delta}pol$.

• 대한의생명과학회지
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• 제10권1호
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• pp.55-63
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• 2004

Bovine leukemia virus (BLV) is a causative agent for lymphoma disease in cattle including cows worldwide. BLV shares similar virion structure and characteristics with other retroviruses. The pol gene of the BLV genome produced reverse transcriptase (RT) and integrase (IN) for important roles for BLV genome integration into host cell chromosomes that is known to be coded in the 3' side of the BLV pol gene (one third portion). In this study, we have sequenced 978 bp in the 3' side of the BLV pol gene from BLV 10C3 in order to determine the BLV IN region of it. And we compared it to the nucleotide sequences of an Australian BLV isolate. As a result, nucleotide sequences of the IN region of the Korean-type BLV pol gene were mutated at a rate of 3.7%. We can confirm that the typical mutations are such as Arg (AGG) $\rightarrow$ Lys (AAG), Thr (ACG) $\rightarrow$ Met (ATG), Ile (ATT) $\rightarrow$ Val (GTT), Asn (ACC) $\rightarrow$ His (CAC), Phe (TTT) $\rightarrow$ Leu (TTG) and Asn (ACC) $\rightarrow$ Asp (GAC). From the analysis of the sequencing data, we were able to determine the zinc-finger-like "HHCC" motif in the amino terminus of BLV IN, that was H-$X_3$-H-$X_{25}-C-X_2$-C. It was also found the DD35E motif in the IN catalytic domain as D-$X_{56}$-D-$X_{35}$-E. It fits very well to the consensus sequences of retroviral IN as well as HHCC motif.

• 미생물학회지
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• 제30권6호
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• pp.472-478
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• 1992

HTLV-1 이 pol 유전자산물을 합성하기 위해서는 genome-size mRNA 를 번역해 나아가는 ribosome 이 -1 방향으로 두차례 frame 을 바꾸어야 한다. 우리는 단 한차계의 frameshifting 만으로도 많은 양의 Gag-Pro-Pol polyprotein 의 합성어 가능하도록 gag 와 pro 유전자의 frame 을 연결시킨 mutant RNA 를 제작하였다. 이 돌연변이를 이용하여 ribosome 의 shift site 하류영역내에 형성이 예상되는 RNA 의 이차구조 또는 삼차 구조가 -1 frameshifting 을 결정하는 인자로서 작용하는지의 여부를 조사하였다. 결손변이주의를 해석한 결과 pro-pol 중첩영역에서 효율적으로 frameshifting 이 일어나기 위해서는 stem-loop 가 필수적으로 형성되어야 하지만 pseudoknot 의 형성은 그다지 중요하지 않다는 사실을 알았다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7375-7379
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• 2013

The main aim of this study was to investigate the roles of GST-${\pi}$ and $pol{\beta}$ genes in the chemoresistance of esophageal carcinoma cells. Eukaryotic expression vectors containing each gene were constructed and transfected into EC9706 cells, and the biological effects of the two genes assessed based on a resistance index. We additionally investigated the in vitro and in vivo anti-resistance effects of GST-${\pi}$ and $pol{\beta}$ genes using recombinant lentiviruses carrying siRNAs against the two genes. Our results showed that upregulation of GST-${\pi}$ and $pol{\beta}$ genes suppresses chemosensitivity of esophageal carcinoma cells to cisplatin, while downregulation of these two genes with RNAi technology reverses this chemoresistance. Multi-site injection of recombinant lentivirus targeting the GST-${\pi}$ gene into transplanted cDDP tumors effectively reversed their chemoresistant phenotype. However, the same treatment against the $pol{\beta}$ gene did not lead to significant efficacy against chemoresistance.

• BMB Reports
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• 제32권5호
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• pp.492-496
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• 1999

We have investigated the biochemical properties of the herpes simplex virus type 1 (HSV-1) DNA polymerase without the UL42 protein (Pol), purified from insect cells infected with a recombinant baculovirus containing the UL30 gene. BSA and DTT have inhibitory effects on dAMP incorporation. Pol showed a greater turnover rate of steady-state single nucleotide incorporation at 12 mM $MgCl_2$ than at 2 mM $MgCl_2$. However, it showed a greater processivity of DNA synthesis at lower $MgCl_2$ concentration (1 mM, 2 mM) than at a higher $MgCl_2$ concentration (12.5 mM). These results are consistent with a slow DNA dissociation at lower $MgCl_2$ concentrations. Pol does not incorporate a correct nucleotide into the primer with an incorrect nucleotide at the end; instead, it preferentially excises the incorrect nucleotide at the 3' end of the primer. Pol has DNA polymerase activity at pHs 6.5 and 7.5 but little at pHs 5.5, 8.5, and 9.5. It has exonuclease activity at pHs 6.5, 7.5, and 8.5 but little at pHs 4.5, 5.5, and 9.5. The finding that Pol has exonuclease activity but not DNA polymerase at pH 8.5 suggests that DNA binds to Pol, but deoxynucleotide binding or incorporation does not occur at pH 8.5.

• BMB Reports
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• 제41권5호
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• pp.358-362
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• 2008

RNA interference (RNAi) is the process of sequence-specific gene silencing. However, RNAi efficiency still needs to be improved for effective inhibition of target genes. We have developed an effective strategy to express multiple shRNAs (small hairpin RNA) simultaneously using multiple RNA Polymerase III (Pol III) promoters in a single vector. Our data demonstrate that multiple shRNAs expressed from Pol III promoters have a synergistic effect in repressing the target gene. Silencing of endogenous cyclophilin A (CypA) or key HIV viral genes by multiple shRNAs results in significant inhibition of the target gene.

• Genomics & Informatics
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• 제3권4호
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• pp.133-141
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• 2005

Most of the endogenous retroviral genes integrated into the primate genome after the split of New World monkeys in the Oligocene era, approximately 33 million years ago. Because they can change the structure of adjacent genes and move between and within chromosomes they may play important roles in evolutionas well as in many kinds of disease and the creation of genetic polymorphism. Comparative analysis of HERVs (human endogenous retroviruses) and their LTR (long terminal repeat) elements in the primate genomes will help us to understand the possible impact of HERV elements in the evolution and phylogeny of primates. For example, HERV-K LTR and SINE-R elements have been identified that have been subject to recent change in the course of primate evolution. They are specific elements to the human genome and could be related to biological function. The HERV-M element is related to the superfamily of HERV-K and is integrated into the periphilin gene as the truncated form, 5'LTR-gag-pol-3'LTR. PCR and RT-PCR approaches indicated that the insertion of various retrotransposable elements in a common ancestor genome may make different transcript variants in different primate species. Examination of the HERV-W elementrevealed that env fragments were detected on human chromosomes 1, 3-7, 12, 14, 17, 20, and X, whilst the pol fragments were detected on human chromosomes 2-8, 10-15, 20, 21, X, and Y. Bioinformatic blast search showed that almost full-length of the HERV-W family was identified on human chromosomes 1-8, 11-15, 17, 18, 21, and X. Expression analysis of HERV-W genes (gag, pol, and env) in human tissues by RT-PCR indicated that gag and pol were expressed in specific tissues, whilst env was constituitively expressed in all tissues examined. DNA sequence based phylogenetic analysis indicated that the gag, pol and env genes have evolved independently during primate evolution. It will thus be of considerable interest to expand the current HERV gene information of various primates and disease tissues.

• Journal of Microbiology and Biotechnology
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• 제31권1호
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• pp.16-24
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• 2021

Hepatitis B virus (HBV) genome P-encoded protein HBV DNA polymerase (Pol) has long been known as a reverse transcriptase during HBV replication. In this study, we investigated the impact of HBV Pol on host cellular processes, mainly apoptosis, and the underlying mechanisms. We showed a marked reduction in apoptotic rates in the HBV Pol-expressed HepG2 cells compared to controls. Moreover, a series of assays, i.e., yeast two-hybrid, GST pull-down, co-immunoprecipitation, and confocal laser scanning microscopy, identified the host factor eEF1A2 to be associated with HBV Pol. Furthermore, knockdown of eEF1A2 gene by siRNA abrogated the HBV Pol-mediated anti-apoptotic effect with apoptosis induced by endoplasmatic reticulum (ER) stress-inducer thapsigargin (TG), thus suggesting that the host factor eEF1A2 is essential for HBV Pol's anti-apoptosis properties. Our findings have revealed a novel role for HBV Pol in its modulation of apoptosis through integrating with eEF1A2.