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Kim BG, Yuk JS, Kim GS, Seo JK, Jin MN, Lee HY, Seo YS, Kim MH, Yang SW, Yoon SH, Byun YS, Kim BO. Effect of early hysterectomy on a risk of incident cardiovascular disease in women: a nationwide population-based cohort study. Eur Heart J 2022. [DOI: 10.1093/eurheartj/ehac544.2495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Aim
Women who inevitably underwent surgical hysterectomy before natural menopause may have an earlier increase in hematocrit and storage iron than women who continue menstruation, thereby increasing the risk of cardiovascular disease (CVD) early. We aimed to evaluate the association of women with hysterectomy vs. without hysterectomy before their 50s with the risk of incident CVD.
Methods
This was a retrospective-cohort study, 135,575 women aged 40 to 50 years in 2011–2014 were extracted from the Korean Health Insurance Review and Assessment Service data and after propensity score matching, 55,539 pairs were included in hysterectomy and non-hysterectomy group respectively. The primary endpoint was major adverse cardiac and cerebrovascular events (MACCE), a composite of cardiovascular death, myocardial infarction (MI), stroke, and coronary artery revascularization.
Results
After adjustment for confounding factors, hysterectomy group had an increased risk of MACCE compared with non-hysterectomy group (hazard ratio [HR], 1.25; 95% confidence interval [CI], 1.09–1.44). Regarding individual outcomes, cardiovascular death, MI, and coronary revascularization were comparable between the groups, whereas, the risk of stroke was significantly higher in hysterectomy group than non-hysterectomy group (HR, 1.31; 95% CI, 1.12–1.53). Even after excluding women who underwent oophorectomy, hysterectomy group had a higher risk of MACCE than non-hysterectomy group (HR, 1.24; 95% CI 1.06–1.44).
Conclusions
Early surgical menopause due to hysterectomy, not hormonal menopause, was associated with an increased risk for a composite of CVD, especially stroke. This suggest that the role of “uterus” as well as sex hormones may be important for the sharp increase in the risk of CVD in women after menopause.
Funding Acknowledgement
Type of funding sources: None.
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Affiliation(s)
- B G Kim
- Inje University Sanggye Paik Hospital, Cardiology , Seoul , Korea (Republic of)
| | - J S Yuk
- Sanggye Paik Hospital, Obstetrics and Gynecology , Seoul , Korea (Republic of)
| | - G S Kim
- Inje University Sanggye Paik Hospital, Cardiology , Seoul , Korea (Republic of)
| | - J K Seo
- Inje University Sanggye Paik Hospital, Cardiology , Seoul , Korea (Republic of)
| | - M N Jin
- Inje University Sanggye Paik Hospital, Cardiology , Seoul , Korea (Republic of)
| | - H Y Lee
- Inje University Sanggye Paik Hospital, Cardiology , Seoul , Korea (Republic of)
| | - Y S Seo
- Sanggye Paik Hospital, Obstetrics and Gynecology , Seoul , Korea (Republic of)
| | - M H Kim
- Sanggye Paik Hospital, Obstetrics and Gynecology , Seoul , Korea (Republic of)
| | - S W Yang
- Sanggye Paik Hospital, Obstetrics and Gynecology , Seoul , Korea (Republic of)
| | - S H Yoon
- Sanggye Paik Hospital, Obstetrics and Gynecology , Seoul , Korea (Republic of)
| | - Y S Byun
- Inje University Sanggye Paik Hospital, Cardiology , Seoul , Korea (Republic of)
| | - B O Kim
- Inje University Sanggye Paik Hospital, Cardiology , Seoul , Korea (Republic of)
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Yim HJ, Kim IH, Suh SJ, Jung YK, Kim JH, Seo YS, Yeon JE, Kim CW, Kwon SY, Park SH, Lee MS, Um SH, Byun KS. Switching to tenofovir vs continuing entecavir for hepatitis B virus with partial virologic response to entecavir: a randomized controlled trial. J Viral Hepat 2018; 25:1321-1330. [PMID: 29772084 DOI: 10.1111/jvh.12934] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 04/16/2018] [Indexed: 12/19/2022]
Abstract
Entecavir 0.5 mg (ETV) is widely used among treatment-naïve chronic hepatitis B (CHB) patients. However, 10%-30% of patients show partial virologic response (PVR) to the drug. If the hepatitis B virus (HBV) continues to replicate, the underlying liver disease may progress. Herein, we compared the efficacy of switching to tenofovir disoproxil fumarate (TDF) with that of continuing ETV in CHB patients with PVR to ETV. This was an open-label randomized controlled trial including CHB patients who had been receiving 0.5 mg of ETV for >12 months, but who still had detectable HBV DNA levels of >60 IU/mL without known resistance to ETV. Sixty patients were enrolled and 45 qualified for the study: Twenty-two patients were randomly assigned into the TDF group and 23 into the ETV group. After 12 months of treatment, the virologic response rate (HBV DNA <20 IU/mL) was significantly higher in the TDF group than in the ETV group, as measured using per-protocol analysis (55% vs 20%; P = .022) and intention-to-treat analysis (50% vs 17.4%; P = .020). The reduction in HBV DNA was greater (-1.13 vs -0.67 log10 IU/mL; P = .024), and the mean HBV DNA level was lower (1.54 vs 2.01 log10 IU/mL; P = .011) in the TDF group than in the ETV group. In conclusion, to achieve optimal response in CHB patients with PVR to ETV, switching to TDF would be a better strategy than continuing ETV. Appropriate modification of therapy would further improve the outcome of chronic HBV infection.
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Affiliation(s)
- H J Yim
- Department of Internal Medicine, Korea University Ansan Hospital, Ansan, South Korea
| | - I H Kim
- Department of Internal Medicine, Chonbuk National University Hospital, Jeonju, South Korea
| | - S J Suh
- Department of Internal Medicine, Korea University Ansan Hospital, Ansan, South Korea
| | - Y K Jung
- Department of Internal Medicine, Korea University Ansan Hospital, Ansan, South Korea.,Department of Internal Medicine, Gachon University Gil Hospital, Incheon, South Korea
| | - J H Kim
- Department of Internal Medicine, Korea University Guro Hospital, Seoul, South Korea
| | - Y S Seo
- Department of Internal Medicine, Korea University Anam Hospital, Seoul, South Korea
| | - J E Yeon
- Department of Internal Medicine, Korea University Guro Hospital, Seoul, South Korea
| | - C W Kim
- Department of Internal Medicine, Uijeongbu St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
| | - S Y Kwon
- Department of Internal Medicine, Konkuk University Hospital, Seoul, South Korea
| | - S H Park
- Department of Internal Medicine, Hallym University Kangnam Sacred Heart Hospital, Seoul, South Korea
| | - M S Lee
- Department of Internal Medicine, Hallym University Kangnam Sacred Heart Hospital, Seoul, South Korea
| | - S H Um
- Department of Internal Medicine, Korea University Anam Hospital, Seoul, South Korea
| | - K S Byun
- Department of Internal Medicine, Korea University Guro Hospital, Seoul, South Korea
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Lee HA, Cho EY, Kim TH, Lee Y, Suh SJ, Jung YK, Kim JH, An H, Seo YS, Kim DS, Yim HJ, Yeon JE, Byun KS, Um SH. Risk Factors for Dropout From the Liver Transplant Waiting List of Hepatocellular Carcinoma Patients Under Locoregional Treatment. Transplant Proc 2018; 50:3521-3526. [PMID: 30577230 DOI: 10.1016/j.transproceed.2018.08.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 08/29/2018] [Indexed: 12/23/2022]
Abstract
BACKGROUND In new organ allocation policy, patients with hepatocellular carcinoma (HCC) experience a 6-month delay in being granted Model for End-Stage Liver Disease exception points. However, it may not be fair for patients at risk of early progression of HCC. METHODS All patients who were diagnosed as United Network for Organ Sharing (UNOS) stage 1 or 2 of HCC between January 2004 and December 2012 were included. Patients who received surgical resection or liver transplant (LT) as a primary treatment and who did not receive any treatment for HCC were excluded. Patients with baseline Model for End-Stage Liver Disease score ≥22 were also excluded because they have a higher chance of receiving LT. Patients who developed extrahepatic progression within 1 year were considered as high-risk for early recurrence after LT. RESULTS A total of 586 patients were included. Mean (SD) age was 59.9 (10.3) years and 409 patients (69.8%) were men. The cumulative incidence of estimated dropout was 8.9% at 6 months; size of the maximum nodule (≥3 cm) and nonachievement of complete response were independent factors. Extrahepatic progression developed in 16 patients (2.7%) within 1 year; size of the maximum nodule (4 cm) and alpha-fetoprotein level (>100 ng/mL) were independent predictors. CONCLUSIONS The estimated dropout rate from the waiting list within 6 months was 8.9%. Advantage points might be needed for patients with maximum nodule size ≥3 cm or those with noncomplete response. However, in patients with maximum nodule size ≥4 cm or alpha-fetoprotein level >100 ng/mL, caution is needed.
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Affiliation(s)
- H A Lee
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - E Y Cho
- Department of Biostatistics, Korea University College of Medicine, Seoul, Korea
| | - T H Kim
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - Y Lee
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - S J Suh
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - Y K Jung
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - J H Kim
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - H An
- Department of Biostatistics, Korea University College of Medicine, Seoul, Korea
| | - Y S Seo
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
| | - D-S Kim
- Department of Surgery, Korea University College of Medicine, Seoul, Korea
| | - H J Yim
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
| | - J E Yeon
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - K S Byun
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - S H Um
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
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Seo YS, Ahn EY, Park J, Kim TY, Hong JE, Kim K, Park Y, Park Y. Catalytic reduction of 4-nitrophenol with gold nanoparticles synthesized by caffeic acid. Nanoscale Res Lett 2017; 12:7. [PMID: 28058640 PMCID: PMC5216008 DOI: 10.1186/s11671-016-1776-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/07/2016] [Indexed: 06/02/2023]
Abstract
In this study, various concentrations of caffeic acid (CA) were used to synthesize gold nanoparticles (CA-AuNPs) in order to evaluate their catalytic activity in the 4-nitrophenol reduction reaction. To facilitate catalytic activity, caffeic acid was removed by centrifugation after synthesizing CA-AuNPs. The catalytic activity of CA-AuNPs was compared with that of centrifuged CA-AuNPs (cf-CA-AuNPs). Notably, cf-CA-AuNPs exhibited up to 6.41-fold higher catalytic activity compared with CA-AuNPs. The catalytic activity was dependent on the caffeic acid concentration, and the lowest concentration (0.08 mM) produced CA-AuNPs with the highest catalytic activity. The catalytic activities of both CA-AuNPs and cf-CA-AuNPs decreased with increasing caffeic acid concentration. Furthermore, a conversion yield of 4-nitrophenol to 4-aminophenol in the reaction mixture was determined to be 99.8% using reverse-phase high-performance liquid chromatography. The product, 4-aminophenol, was purified from the reaction mixture, and its structure was confirmed by 1H-NMR. It can be concluded that the removal of the reducing agent, caffeic acid in the present study, significantly enhanced the catalytic activity of CA-AuNPs in the 4-nitrophenol reduction reaction.
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Affiliation(s)
- Yu Seon Seo
- College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 50834 Republic of Korea
| | - Eun-Young Ahn
- College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 50834 Republic of Korea
| | - Jisu Park
- College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 50834 Republic of Korea
| | - Tae Yoon Kim
- College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 50834 Republic of Korea
| | - Jee Eun Hong
- College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 50834 Republic of Korea
| | - Kyeongsoon Kim
- Department of Pharmaceutical Engineering, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 50834 Republic of Korea
| | - Yohan Park
- College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 50834 Republic of Korea
| | - Youmie Park
- College of Pharmacy and Inje Institute of Pharmaceutical Sciences and Research, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 50834 Republic of Korea
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Kim HS, Seo YS, Kim K, Han JW, Park Y, Cho S. Concentration Effect of Reducing Agents on Green Synthesis of Gold Nanoparticles: Size, Morphology, and Growth Mechanism. Nanoscale Res Lett 2016; 11:230. [PMID: 27119158 PMCID: PMC4848276 DOI: 10.1186/s11671-016-1393-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Accepted: 04/04/2016] [Indexed: 05/29/2023]
Abstract
Under various concentration conditions of reducing agents during the green synthesis of gold nanoparticles (AuNPs), we obtain the various geometry (morphology and size) of AuNPs that play a crucial role in their catalytic properties. Through both theoretical and experimental approaches, we studied the relationship between the concentration of reducing agent (caffeic acid) and the geometry of AuNPs. As the concentration of caffeic acid increases, the sizes of AuNPs were decreased due to the adsorption and stabilizing effect of oxidized caffeic acids (OXCAs). Thus, it turns out that optimal concentration exists for the desired geometry of AuNPs. Furthermore, we investigated the growth mechanism for the green synthesis of AuNPs. As the caffeic acid is added and adsorbed on the surface of AuNPs, the aggregation mechanism and surface free energy are changed and consequently resulted in the AuNPs of various geometry.
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Affiliation(s)
- Hyun-Seok Kim
- National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-744, Republic of Korea
| | - Yu Seon Seo
- College of Pharmacy, Inje University, 197 Inje-ro, Gimhae, 621-749, Republic of Korea
| | - Kyeounghak Kim
- Department of Chemical Engineering, University of Seoul, Seoul, 130-743, Republic of Korea
| | - Jeong Woo Han
- Department of Chemical Engineering, University of Seoul, Seoul, 130-743, Republic of Korea
| | - Youmie Park
- College of Pharmacy, Inje University, 197 Inje-ro, Gimhae, 621-749, Republic of Korea
| | - Seonho Cho
- National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-744, Republic of Korea.
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Jang SH, Seo YS. Injury of the Contralateral Lower Ascending Reticular Activating System by an Intracerebral Hemorrhage. AJNR Am J Neuroradiol 2015; 36:E58-9. [PMID: 26113072 DOI: 10.3174/ajnr.a4446] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- S H Jang
- Department of Physical Medicine and Rehabilitation College of Medicine, Yeungnam University Daegu, Republic of Korea
| | - Y S Seo
- Department of Physical Medicine and Rehabilitation College of Medicine, Yeungnam University Daegu, Republic of Korea
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Seo YS, Cha SH, Yoon HR, Kang YH, Park Y. Caffeic acid: potential applications in nanotechnology as a green reducing agent for sustainable synthesis of gold nanoparticles. Nat Prod Commun 2015; 10:627-630. [PMID: 25973494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023] Open
Abstract
The sustainable synthesis of gold nanoparticles from gold ions was conducted with caffeic acid as a green reducing agent. The formation of gold nanoparticles was confirmed by spectroscopic and microscopic methods. Spherical nanoparticles with an average diameter of 29.99 ± 7.43 nm were observed in high- resolution transmission electron microscopy and atomic force microscopy images. The newly prepared gold nanoparticles exhibited catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. This system enables the preparation of green catalysts using plant natural products as reducing agents, which fulfills the growing need for sustainability initiatives.
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Seo YS, Cha SH, Cho S, Yoon HR, Kang YH, Park Y. Caffeic Acid: Potential Applications in Nanotechnology as a Green Reducing Agent for Sustainable Synthesis of Gold Nanoparticles. Nat Prod Commun 2015. [DOI: 10.1177/1934578x1501000424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The sustainable synthesis of gold nanoparticles from gold ions was conducted with caffeic acid as a green reducing agent. The formation of gold nanoparticles was confirmed by spectroscopic and microscopic methods. Spherical nanoparticles with an average diameter of 29.99 ± 7.43 nm were observed in high-resolution transmission electron microscopy and atomic force microscopy images. The newly prepared gold nanoparticles exhibited catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. This system enables the preparation of green catalysts using plant natural products as reducing agents, which fulfills the growing need for sustainability initiatives.
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Affiliation(s)
- Yu Seon Seo
- College of Pharmacy, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 621-749, Republic of Korea
| | - Song-Hyun Cha
- National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744, Republic of Korea
| | - Seonho Cho
- National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744, Republic of Korea
| | - Hye-Ran Yoon
- College of Pharmacy, Duksung Women's University, 33 Samyangro 144-gil, Seoul, 132-714, Republic of Korea
| | - Young-Hwa Kang
- Division of Applied Biosciences, College of Agriculture & Life Sciences, Kyungpook National University, 1370 Sankyuk, Daegu 702-701, Republic of Korea
| | - Youmie Park
- College of Pharmacy, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 621-749, Republic of Korea
- National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744, Republic of Korea
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Kang OH, Kim SB, Seo YS, Joung DK, Mun SH, Choi JG, Lee YM, Kang DG, Lee HS, Kwon DY. Curcumin decreases oleic acid-induced lipid accumulation via AMPK phosphorylation in hepatocarcinoma cells. Eur Rev Med Pharmacol Sci 2013; 17:2578-2586. [PMID: 24142602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
BACKGROUND AND OBJECTIVES Non-alcoholic fatty liver disease (NAFLD) is one of the most common metabolic syndromes and is characterized by the accumulation of hepatic triglycerides (TG), which result from an imbalance between uptake, synthesis, export, and oxidation of fatty acids. Curcumin is a polyphenol derived from the herbal remedy and dietary spice turmeric, was found to prevent obesity and diabetes in mouse models. However, a hypolipidemic effect of curcumin in oleic acid- induced hepatocarcinoma cells has not been reported. In this study, we examined the effect of curcumin on reducing lipid accumulation in hepatic cells. MATERIALS AND METHODS Hepatocytes were treated with oleic acid (OA) containing with or without curcumin to observe the lipid accumulation by Oil Red O stain. We also tested the effects of curcumin on triglycerides (TG) and total cholesterol (TC) in HepG2 cells. Western blot and reverse transcription polymerase chain reaction (RT-PCR) was used to measure sterol regulatory element binding proteins-1 (SREBP-1), fatty acid synthase (FAS), peroxisome proliferator-activated receptor (PPAR)-α, and adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) expression. RESULTS Curcumin suppressed OA-induced lipid accumulation and TG and TC levels. Also, curcumin decreased hepatic lipogenesis such as SREBP-1, and FAS. Besides, we also found out the antioxidative effect of curcumin by increasing the expression of PPARα. Curcumin increased AMPK phosphorylation in hepatocytes. CONCLUSIONS These results indicated that curcumin has the same ability to activate AMPK and then reduce SREBP-1, and FAS expression, finally leading to inhibit hepatic lipogenesis and hepatic antioxidative ability. In this report, we found curcumin exerted a regulatory effect on lipid accumulation by decreasing lipogenesis in hepatocyte. Therefore, curcumin extract may be active in the prevention of fatty liver.
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Affiliation(s)
- O H Kang
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Iksan, Jeonbuk, Republic of Korea.
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Chae HS, Kang OH, Keum JH, Kim SB, Mun SH, Seo YS, Kim MR, Choi JG, Shin DW, Oh YC, Ma JY, Kwon DY. Anti-inflammatory effects of Hylomecon hylomeconoides in RAW 264.7 cells. Eur Rev Med Pharmacol Sci 2012; 16 Suppl 3:121-125. [PMID: 22957426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND AND OBJECTIVES Papaveraceae serve as a rich source of various alkaloids which have anti-inflammatory effect. MATERIALS AND METHODS In this study, we investigated the effect of Hylomecon hylomeconoides ethanol extract (HHE) on lipopolysaccharide (LPS)-induced NO and interleukin-6 (IL-6) production in RAW 264.7 cells. RESULTS HHE inhibited LPS-induced NO and IL-6 production. Moreover, HHE suppressed the phosphorylation of ERK1/2 and p38 in LPS-induced RAW 264.7 in a dose-dependent manner. Furthermore, major constituents, dihydrosanguinarine and 6-methoxydihydrosanguinarine, of the chloroform-soluble extract were analyzed. CONCLUSIONS Taken together, the results of this study indicate that the anti-inflammatory effects of HHE may occur via the inhibition of NO and IL-6 expression through the down-regulation of MAP kinase (ERK1/2, p38) phosphorylation in RAW 264.7 cells.
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Affiliation(s)
- H S Chae
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang, Republic of Korea
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Yun MH, Seo YS, Kang HS, Lee KG, Kim JH, An H, Yim HJ, Keum B, Jeen YT, Lee HS, Chun HJ, Um SH, Kim CD, Ryu HS. The effect of the respiratory cycle on liver stiffness values as measured by transient elastography. J Viral Hepat 2011; 18:631-6. [PMID: 21029256 DOI: 10.1111/j.1365-2893.2010.01376.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The findings of several studies suggest that liver stiffness values can be affected by the degree of intrahepatic congestion respiration influence intrahepatic blood volume and may affect liver stiffness. We evaluated the influence of respiration on liver stiffness. Transient elastography (TE) was performed at the end of inspiration and at the end of expiration in patients with chronic liver disease. The median values obtained during the inspiration set and during the expiration set were defined as inspiratory and expiratory liver stiffness, respectively. A total of 123 patients with chronic liver disease were enrolled (mean age 49years; 64.2% men). Liver cirrhosis coexisted in 29 patients (23.6%). Expiratory liver stiffness was significantly higher than inspiratory liver stiffness (8.7 vs 7.9kPa, P=0.001), while the expiratory interquartile range/median ratio (IQR ratio) did not differ from the inspiratory IQR ratio. Expiratory liver stiffness was significantly higher than inspiratory liver stiffness in 49 (39.8%) patients (HE group), expiratory liver stiffness was significantly lower than inspiratory stiffness in 15 (12.2%) patients, and there was no difference in 59 (48.0%) patients. Liver cirrhosis was more frequent in those who had a lower liver stiffness reading in expiration, and only the absence of liver cirrhosis was significantly associated with a higher reading in expiration in multivariate analysis. In conclusion, liver stiffness was significantly elevated during expiration especially in patients without liver cirrhosis. The effect of respiration should be kept in mind during TE readings.
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Affiliation(s)
- M H Yun
- Departments of Internal Medicine, Korea University College of Medicine, Seoul, Korea
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Park S, Chun HJ, Keum B, Lee BJ, Seo YS, Kim YS, Park JJ, Jeen YT, Lee HS, Um SH, Kim CD, Ryu HS. Successful salvage treatment of peptic duodenal stenosis with repeat insertion of self-expanding stent after failed balloon dilation. Endoscopy 2011; 43 Suppl 2 UCTN:E187-8. [PMID: 21590595 DOI: 10.1055/s-0030-1256323] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- S Park
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Hanil General Hospital, KEPCO Medical Foundation, Seoul, Korea
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Kim ES, Chun HJ, Keum B, Seo YS, Kim YS, Jeen YT, Lee HS, Um SH, Kim CD, Ryu HS. Endoscopic retrieval of a metal stent embedded in the colon wall. Endoscopy 2011; 43 Suppl 2 UCTN:E139-40. [PMID: 21425015 DOI: 10.1055/s-0030-1256206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Affiliation(s)
- E S Kim
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
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Kim JH, Yim HJ, Jung ES, Jung YK, Kim JH, Seo YS, Yeon JE, Lee HS, Um SH, Byun KS. Virologic and biochemical responses to clevudine in patients with chronic HBV infection-associated cirrhosis: data at week 48. J Viral Hepat 2011; 18:287-93. [PMID: 20367793 DOI: 10.1111/j.1365-2893.2010.01304.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Clevudine shows high rates of virologic and biochemical responses in patients with chronic hepatitis B. However, the efficacy and safety of clevudine in patients with cirrhosis are unknown. The aims of this study were to evaluate the safety and to assess the virologic and the biochemical responses to clevudine in patients with cirrhosis with chronic hepatitis B virus (HBV) infection. We reviewed data from treatment-naïve patients with chronic hepatitis B with and without cirrhosis who started clevudine between April 2007 and March 2008 (n = 52, hepatitis B without cirrhosis n = 21 and chronic hepatitis B with cirrhosis n = 31) at Korea University Ansan/Guro Hospital. All of the patients were treated for more than 48 weeks. The mean age was older in the patients with cirrhosis. Baseline HBV DNA levels were 6.9 and 7.78 log copies/mL (P = 0.042), and alanine aminotransferase (ALT) levels were 104.9 and 147.4 IU/L (P = 0.204), for those with and without cirrhosis, respectively. Virologic response (HBV DNA <1000 copies/mL) (87.1%vs 71.4%, P = 0.24) and biochemical response (83.9%vs 80.9%, P = 0.99) at week 48 were not significantly different between the two groups. Early virologic response at week 12 was even higher in the patients with cirrhosis (61.3%vs 28.6%, P = 0.026). Neither ALT flare nor newly onset hepatic decompensation was found in the patients with cirrhosis, whereas ALT flare was transiently observed in 14.3% of the chronic hepatitis group. In conclusion, although clevudine may produce a transient elevation of ALT during the early treatment period, such findings were not observed in patients with cirrhosis and the virologic and biochemical responses of the groups were comparable.
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Affiliation(s)
- J H Kim
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
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Affiliation(s)
- J J Hyun
- Department of Internal Medicine, Institute of Digestive Disease and Nutrition, Korea University College of Medicine, Seoul, Korea
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Park S, Chun HJ, Keum B, Seo YS, Kim YS, Jeen YT, Lee HS, Um SH, Kim CD, Ryu HS. Anaphylactic shock-induced ischemic proctocolitis following bee stings: first case report. Endoscopy 2010; 42 Suppl 2:E153-4. [PMID: 20556709 DOI: 10.1055/s-0029-1244101] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- S Park
- Department of Internal Medicine, Institute of Digestive Disease and Nutrition, Korea University College of Medicine, Seoul, Korea
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17
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Kim SU, Seo YS, Cheong JY, Kim MY, Kim JK, Um SH, Cho SW, Paik SK, Lee KS, Han KH, Ahn SH. Factors that affect the diagnostic accuracy of liver fibrosis measurement by Fibroscan in patients with chronic hepatitis B. Aliment Pharmacol Ther 2010; 32:498-505. [PMID: 20491742 DOI: 10.1111/j.1365-2036.2010.04353.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Interquartile range/median value (IQR/M) of liver stiffness measurement (LSM) is a factor in chronic hepatitis C (CHC) leading to over estimation of fibrosis by Fibroscan. AIM To investigate factors that affect the accuracy of LSM in chronic hepatitis B (CHB). METHODS One hundred and ninety-nine patients were enrolled. Only procedures yielding > or =10 valid measurements were considered reliable. Liver fibrosis was evaluated using the Batts and Ludwig system. Liver biopsy (LB) specimens <15 mm were considered ineligible. RESULTS The mean age (142 men and 57 women) was 40.1 years. A significant discordance (discordance of at least two stages between LB and LSM) was identified in 38 (19.1%) and 47 (23.6%) patients respectively, according to Marcellin et al. and Chan et al.'s cutoff values. In multivariate analyses, BMI and fibrosis stage (F0-2 vs. F3-4) were identified as independent predictors for significant discordance (P = 0.040; hazard ratio [HR], 1.126; 95% confidence interval [CI], 1.005-1.261 and P = 0.036; HR, 0.450; 95% CI, 0.213-0.949 respectively) with Marcellin et al.'s cutoffs, whereas fibrosis stage was the only independent predictor (P = 0.004; HR, 0.300; 95% CI, 0.131-0.685) with Chan's cutoffs. CONCLUSIONS Success rate and IQR/M were not predictive factors of the accuracy for diagnosing liver fibrosis by Fibroscan in CHB. Fibrosis stage (F0-2) was the only factor to predict significant discordance between LB and LSM.
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Affiliation(s)
- S U Kim
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
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18
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Kim J, Chun HJ, Hyun JJ, Keum B, Seo YS, Kim YS, Jeen YT, Lee HS, Um SH, Kim CD, Ryu HS. Splenic infarction after cyanoacrylate injection for fundal varices. Endoscopy 2010; 42 Suppl 2:E118. [PMID: 20306402 DOI: 10.1055/s-0029-1243984] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- J Kim
- Department of Internal Medicine, Korea University College of Medicine, Institute of Digestive Disease and Nutrition, Seoul, Republic of Korea.
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Hyun JJ, Chun HJ, Keum B, Seo YS, Kim YS, Jeen YT, Lee HS, Um SH, Kim CD, Ryu HS. Weblike stenosis due to gastroesophageal reflux disease, treated with an insulation-tipped diathermic knife-2 (IT-2). Endoscopy 2010; 42 Suppl 2:E110. [PMID: 20306396 DOI: 10.1055/s-0029-1243946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Affiliation(s)
- J J Hyun
- Department of Internal Medicine, Institute of Digestive Disease and Nutrition, Korea University College of Medicine, Seoul, Korea
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Kim J, Keum B, Seo YS, Kim YS, Jeen YT, Chun HJ, Um SH, Kim CD, Ryu HS. Primary malignant melanoma with surrounding melanosis in the anorectum. Endoscopy 2010; 42 Suppl 2:E47. [PMID: 20157885 DOI: 10.1055/s-0029-1215416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Affiliation(s)
- J Kim
- Department of Internal Medicine, Institute of Digestive Disease and Nutrition, Korea University College of Medicine, Seoul, Korea
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Park SC, Jeen YT, Keum B, Seo YS, Kim YS, Chun HJ, Um SH, Kim CD, Ryu HS. Education and Imaging. Gastrointestinal: a retroperitoneal liposarcoma that formed a fistula into the descending colon. J Gastroenterol Hepatol 2010; 25:1013. [PMID: 20546457 DOI: 10.1111/j.1440-1746.2010.06344.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Affiliation(s)
- S C Park
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
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Park S, Chun HJ, Keum B, Seo YS, Jeen YT, Um SH, Kim CD, Ryu HS, Park SS, Kim J. Successful hybrid NOTES resection of early gastric cancer in a patient with concomitant advanced colon cancer. Endoscopy 2010; 42 Suppl 2:E1-2. [PMID: 20066601 DOI: 10.1055/s-0029-1215255] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Affiliation(s)
- S Park
- Department of Internal Medicine, Institute of Digestive Disease and Nutrition, Korea University College of Medicine, Seoul, Korea
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Affiliation(s)
- E S Kim
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
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Park S, Jeen YT, Kwon YD, Keum B, Seo YS, Kim YS, Chun HJ, Um SH, Kim CD, Ryu HS. Successfully cured primary esophageal lymphoma in a patient with acquired immune deficiency syndrome (AIDS). Endoscopy 2009; 41 Suppl 2:E148-9. [PMID: 19544273 DOI: 10.1055/s-0028-1119723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Affiliation(s)
- S Park
- Department of Internal Medicine, Institute of Digestive Disease and Nutrition, Korea University College of Medicine, Seoul, Korea
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25
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Jing HY, Hong DH, Kwak BD, Choi DJ, Shin K, Yu CJ, Kim JW, Noh DY, Seo YS. X-ray reflectivity study on the structure and phase stability of mixed phospholipid multilayers. Langmuir 2009; 25:4198-4202. [PMID: 19714836 DOI: 10.1021/la802868r] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Vertically oriented multilayers composed of two saturated phospholipids, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphoserine (DPPS), were deposited on silicon. X-ray reflectivity was used to investigate the structures of the variously mixed phospholipid multilayers as a function of composition. Then, the phase stability was investigated at various annealing temperatures under humid conditions. The results indicated that the lipid spacing of the mixed phospholipid multilayers varied systematically as a function of the DPPC/DPPS ratio and that no macroscopic phase separation occurred during the annealing process under both dry and humid conditions.
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Affiliation(s)
- H Y Jing
- Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology, Sogang-HANARO Joint Center for Biological Interfaces, Sogang University, Seoul 121-742, Korea
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26
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Yeon JE, Yoo W, Hong SP, Chang YJ, Yu SK, Kim JH, Seo YS, Chung HJ, Moon MS, Kim SO, Byun KS, Lee CH. Resistance to adefovir dipivoxil in lamivudine resistant chronic hepatitis B patients treated with adefovir dipivoxil. Gut 2006; 55:1488-95. [PMID: 16461777 PMCID: PMC1856440 DOI: 10.1136/gut.2005.077099] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Adefovir dipivoxil (ADV) is a potent nucleotide analogue against both the wild-type and lamivudine (LMV) resistant hepatitis B virus (HBV). The cumulative incidence of ADV resistant mutations in the nucleoside/-tide treatment naive chronic hepatitis B patient (CHB) at weeks 48, 96, and 144 was 0, 0.8-3%, and approximately 5.9%, respectively. AIMS The aim of this study was to characterise the genotypic and phenotypic mutation profiles to ADV in 67 LMV resistant CHB patients who were treated with ADV. METHODS Serum HBV DNA was quantified by real time polymerase chain reaction. The ADV mutant was detected using matrix assisted laser desorption/ionisation time of flight mass spectrometry based genotyping assays, termed restriction fragment mass polymorphism (RFMP). RESULTS RFMP analysis revealed that a total of 11 amino acid substitutions developed in the rt domain of the HBV polymerase in nine patients. The cumulative incidence of genotypic ADV resistance at months 12 and 24 was 6.4% and 25.4%, respectively. The rtA181V, rtN236T, and rtA181T mutations were detected in five, four, and two of the 67 patients at treatment months 12-17, 3-19, and 7-20, respectively. Serial quantification of serum HBV DNA revealed that two patients with the rtA181V mutation, with or without the rtN236T mutation, and one patient with the rtA181T mutation displayed HBV DNA rebound. CONCLUSION Emergence of the ADV mutation in LMV resistant patients who are treated with ADV appeared to present earlier and more frequently than was reported in previous studies on nucleoside/-tide treatment naive patients.
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Affiliation(s)
- J E Yeon
- Korea University Medical College Guro Hospital, Department of Internal Medicine, Division of Gastroenterology and Hepatology, Guro-gu Guro-dong gil 97, Seoul, Korea
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Yang SH, Seo YS, Lee YS, Choi SJ, Kim YA, Kim JH. Prenatal sonographic diagnosis of isolated agnathia: a case report. Ultrasound Obstet Gynecol 2003; 22:190-193. [PMID: 12905517 DOI: 10.1002/uog.195] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Agnathia is a rare malformation characterized by the absence of the mandible, microstomia, aplasia or hypoplasia of the tongue, and low-set or medially fused ears. It occurs alone or in combination with a variety of malformations such as holoprosencephaly. All previous cases of the prenatal diagnosis of agnathia have been accompanied with fatal anomalies. We report here the first case of isolated agnathia, which was diagnosed by prenatal sonography at 32 weeks of gestation. In this case, prenatal sonographic examination showed the severe defect of the chin, small opening of the mouth and severe polyhydramnios. There was no sonographic evidence of holoprosencephaly or anomalies in other organ systems. The diagnosis was confirmed postnatally.
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Affiliation(s)
- S H Yang
- Department of Obstetrics and Gynecology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea.
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Abstract
Using the 10-item Spielberger Trait Anger Scale, the authors interviewed 145 patients with stroke regarding inability to control anger or aggression (ICAA). Poststroke depression and emotional incontinence were also assessed. ICAA was present in 47 patients (32%) and was closely related to motor dysfunction, dysarthria, emotional incontinence, and lesions affecting frontal-lenticulocapsular-pontine base areas. ICAA seems to be one of the major behavioral symptoms in patients with stroke.
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Affiliation(s)
- J S Kim
- Department of Neurology, University of Ulsan, Asan Medical Center, Seoul, Korea.
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Hübscher U, Seo YS. Replication of the lagging strand: a concert of at least 23 polypeptides. Mol Cells 2001; 12:149-57. [PMID: 11710514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
DNA replication is one of the most important events in living cells, and it is still a key problem how the DNA replication machinery works in its details. A replication fork has to be a very dynamic apparatus since frequent DNA polymerase switches from the initiating DNA polymerase alpha to the processive elongating DNA polymerase delta occur at the leading strand (about 8 x 10(4) fold on both strands in one replication round) as well as at the lagging strand (about 2 x 10(7) fold on both strands in one replication round) in mammalian cells. Lagging strand replication involves a very complex set of interacting proteins that are able to frequently initiate, elongate and process Okazaki fragments of 180 bp. Moreover, key proteins of this important process appear to be controlled by S-phase check-point proteins. It became furthermore clear in the last few years that DNA replication cannot be considered uncoupled from DNA repair, another very important event for any living organism. The reconstitution of nucleotide excision repair and base excision repair in vitro with purified components clearly showed that the DNA synthesis machinery of both of these macromolecular events are similar and do share many components of the lagging strand DNA synthesis machinery. In this minireview we summarize our current knowledge of the components involved in the execution and regulation of DNA replication at the lagging strand of the replication fork.
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Affiliation(s)
- U Hübscher
- Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich, Switzerland.
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Abstract
Extensive work on the maturation of lagging strands during the replication of simian virus 40 DNA suggests that the initiator RNA primers of Okazaki fragments are removed by the combined action of two nucleases, RNase HI and Fen1, before the Okazaki fragments join. Despite the well established in vitro roles of these two enzymes, genetic analyses in yeast revealed that null mutants of RNase HI and/or Fen1 are not lethal, suggesting that an additional enzymatic activity may be required for the removal of RNA. One such enzyme is the Saccharomyces cerevisiae Dna2 helicase/endonuclease, which is essential for cell viability and is well suited to removing RNA primers of Okazaki fragments. In addition, Dna2 interacts genetically and physically with several proteins involved in the elongation or maturation of Okazaki fragments. Here we show that the endonucleases Dna2 and Fen1 act sequentially to facilitate the complete removal of the primer RNA. The sequential action of these enzymes is governed by a single-stranded DNA-binding protein, replication protein-A (RPA). Our results demonstrate that the processing of Okazaki fragments in eukaryotes differs significantly from, and is more complicated than, that occurring in prokaryotes. We propose a novel biochemical mechanism for the maturation of eukaryotic Okazaki fragments.
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Affiliation(s)
- S H Bae
- National Creative Research Initiative Center for Cell Cycle Control, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 300 Chunchun-Dong, Changan-Ku, Suwon, Kyunggi-Do 440-746, Korea
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Bae SH, Kim JA, Choi E, Lee KH, Kang HY, Kim HD, Kim JH, Bae KH, Cho Y, Park C, Seo YS. Tripartite structure of Saccharomyces cerevisiae Dna2 helicase/endonuclease. Nucleic Acids Res 2001; 29:3069-79. [PMID: 11452032 PMCID: PMC55803 DOI: 10.1093/nar/29.14.3069] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In order to gain insights into the structural basis of the multifunctional Dna2 enzyme involved in Okazaki fragment processing, we performed biochemical, biophysical and genetic studies to dissect the domain structure of Dna2. Proteolytic digestion of Dna2 using subtilisin produced a 127 kDa polypeptide that lacked the 45 kDa N-terminal region of Dna2. Further digestion generated two subtilisin-resistant core fragments of approximately equal size, 58 and 60 kDa. Surprisingly, digestion resulted in a significant (3- to 8-fold) increase in both ATPase and endonuclease activities compared to the intact enzyme. However, cells with a mutant DNA2 allele lacking the corresponding N-terminal region were severely impaired in growth, being unable to grow at 37 degrees C, indicating that the N-terminal region contains a domain critical for a cellular function(s) of Dna2. Analyses of the hydrodynamic properties of and in vivo complex formation by wild-type and/or mutant Dna2 lacking the N-terminal 45 kDa domain revealed that Dna2 is active as the monomer and thus the defect in the mutant Dna2 protein is not due to its inability to multimerize. In addition, we found that the N-terminal 45 kDa domain interacts physically with a central region located between the two catalytic domains. Our results suggest that the N-terminal 45 kDa domain of Dna2 plays a critical role in regulation of the enzymatic activities of Dna2 by serving as a site for intra- and intermolecular interactions essential for optimal function of Dna2 in Okazaki fragment processing. The possible mode of regulation of Dna2 is discussed based upon our recent finding that replication protein A interacts functionally and physically with Dna2 during Okazaki fragment processing.
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Affiliation(s)
- S H Bae
- National Creative Research Initiative Center for Cell Cycle Control, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 300 Chunchun-Dong, Changan-Ku, Suwon, Kyunggi-Do 440-746, Korea
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Bae SH, Seo YS. Characterization of the enzymatic properties of the yeast dna2 Helicase/endonuclease suggests a new model for Okazaki fragment processing. J Biol Chem 2000; 275:38022-31. [PMID: 10984490 DOI: 10.1074/jbc.m006513200] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Saccharomyces cerevisiae Dna2, which contains single-stranded DNA-specific endonuclease activity, interacts genetically and physically with Fen-1, a structure-specific endonuclease implicated in Okazaki fragment maturation during lagging strand synthesis. In this report, we investigated the properties of the Dna2 helicase/endonuclease activities in search of their in vivo physiological functions in eukaryotes. We found that the Dna2 helicase activity translocates in the 5' to 3' direction and uses DNA with free ends as the preferred substrate. Furthermore, the endonucleolytic cleavage activity of Dna2 was markedly stimulated by the presence of an RNA segment at the 5'-end of single-stranded DNA and occurred within the DNA, ensuring the complete removal of the initiator RNA segment on the Okazaki fragment. In addition, we demonstrated that the removal of pre-existing initiator 5'-terminal RNA segments depended on a displacement reaction carried out during the DNA polymerase delta-catalyzed elongation of the upstream Okazaki fragments. These properties indicate that Dna2 is well suited to remove the primer RNA on the Okazaki fragment. Based op this information, we propose a new model in which Dna2 plays a direct role in Okazaki fragment maturation in conjunction with Fen-1.
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Affiliation(s)
- S H Bae
- National Creative Research Initiative Center for Cell Cycle Control, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 300 Chunchun-Dong, Changan-Ku, Suwon-Si, Kyunggi-Do, 440-746, Korea
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Suk K, Hwang DY, Kim S, Kim YH, Kim KA, Seo YS, Suh Y, Lee SB, Namkung Y, Shin HS, Lee MS. Identity of mouse IA-2 and PTP35 genes of the tyrosine phosphatase family, and their expression in neuroendocrine tissues. Diabetes Res Clin Pract 2000; 50:17-26. [PMID: 10936665 DOI: 10.1016/s0168-8227(00)00162-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Recently, IA-2, one of the major diabetic autoantigens, and PTP35 cDNA were independently isolated by subtraction cloning using insulinoma cells and a polymerase chain reaction (PCR)-based search for conserved sequences using NIH3T3 fibroblast cell line, respectively. By Southern blot analysis and nucleotide sequence determination of reverse transcription PCR products, we showed that IA-2 and PTP35 are identical and exist as a single gene in a mouse genome. The expression of IA-2/PTP35 messages was detected by northern blot analysis in MIN6N8 cells, an insulinoma cell line derived from non-obese diabetic mice, but its expression level was not affected by the ambient glucose level, phorbol-12-myristate 13-acetate or tumour necrosis factor-alpha. We also generated polyclonal antibodies to murine IA-2/PTP35 by immunization with recombinant proteins. Subsequent immunohistochemical analysis using these polyclonal antibodies disclosed that IA-2/PTP35 is strongly expressed in mouse neuroendocrine tissues such as pancreatic islets and the hypothalamus-pituitary gland. These results suggest that IA-2/PTP35 functions primarily in neuroendocrine tissues.
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Affiliation(s)
- K Suk
- Clinical Research Center, Samsung Biomedical Research Institute, Seoul, South Korea
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Lee AH, Hong JH, Seo YS. Tumour necrosis factor-alpha and interferon-gamma synergistically activate the RANTES promoter through nuclear factor kappaB and interferon regulatory factor 1 (IRF-1) transcription factors. Biochem J 2000; 350 Pt 1:131-8. [PMID: 10926836 PMCID: PMC1221234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Inflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) synergistically activate expression of the RANTES (regulated upon activation, normal T-cell expressed and secreted) gene, which plays a crucial role in the chemoattraction of leukocytes during the inflammatory response. To understand at the molecular level the mechanism by which the two cytokines activate RANTES gene expression, we determined the requirement of cis-acting elements in the RANTES promoter and trans-acting factors. The murine RANTES promoter contained one putative interferon regulatory factor, IRF, and three putative nuclear factor kappaB (NF-kappaB) binding sites. Specific destruction of the IRF binding site and one of the three NF-kappaB binding sites abolished the inducibility of promoter activity by IFN-gamma and TNF-alpha, respectively. In contrast, mutation of the other two putative NF-kappaB binding sites did not affect RANTES promoter activity significantly. In addition, the RANTES promoter was stimulated by co-transfection of plasmids that expressed either p65, an NF-kappaB family protein, or the IRF-1 transcription factor. RANTES promoters with mutations in the NF-kappaB or IRF binding sites were not stimulated by p65 or IRF-1 expression, respectively. In electrophoretic mobility-shift and immunologic assays, we showed that IRF-1 was induced after cells were treated with IFN-gamma and that NF-kappaB was activated by TNF-alpha treatment. These results demonstrate that both NF-kappaB and IRF-1 transcription factors mediate the induction of RANTES expression via their cognate cis-acting elements when cells are stimulated by TNF-alpha and IFN-gamma.
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Affiliation(s)
- A H Lee
- National Creative Research Initiative Center for Cell Cycle Control, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 300 Chunchun-Dong, Changan-Ku, Suwon-Si, Kyunggi-Do, 440-746, South Korea
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Lee KH, Kim DW, Bae SH, Kim JA, Ryu GH, Kwon YN, Kim KA, Koo HS, Seo YS. The endonuclease activity of the yeast Dna2 enzyme is essential in vivo. Nucleic Acids Res 2000; 28:2873-81. [PMID: 10908349 PMCID: PMC102684 DOI: 10.1093/nar/28.15.2873] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2000] [Accepted: 06/14/2000] [Indexed: 11/12/2022] Open
Abstract
Dna2 is a multifunctional enzyme in yeast that possesses endonuclease activity well suited to remove RNA-DNA primers of Okazaki fragments, raising the question of whether endonuclease activity is essential for in vivo Dna2 function. Systematic site-directed mutations of amino acid residues in Saccharomyces cerevisiae DNA2 conserved in the central region of many eukaryotic DNA2 homologs allowed us to identify mutant dna2 alleles that were divided into three groups based on the viability of the mutant cells: (i) viable; (ii) inviable only when expression was repressed; (iii) inviable. Biochemical analyses of recombinant mutant Dna2 proteins isolated from the latter two groups revealed that they possessed normal ATPase/helicase activity, but were impaired in their endonuclease activity. Cells expressing mutant Dna2 enzymes partially impaired in endonuclease activity were viable, but were unable to grow when expression of their mutant Dna2 enzymes was further reduced. Their growth was restored when the mutant Dna2 proteins decreased in nuclease activity were induced to overexpress. In contrast, mutant Dna2 proteins lacking endonuclease activity did not allow cells to grow under any conditions tested. These in vivo and in vitro results demonstrate that the endonuclease activity of Dna2 is essential for Okazaki fragment processing.
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Affiliation(s)
- K H Lee
- National Creative Research Initiative Center for Cell Cycle Control, Sungkyunkwan University School of Medicine, 300 Chunchun-Dong, Changan-Ku, Suwon-Si, Kyunggi-Do 440-746, Korea
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36
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Kang HY, Choi E, Bae SH, Lee KH, Gim BS, Kim HD, Park C, MacNeill SA, Seo YS. Genetic analyses of Schizosaccharomyces pombe dna2(+) reveal that dna2 plays an essential role in Okazaki fragment metabolism. Genetics 2000; 155:1055-67. [PMID: 10880469 PMCID: PMC1461167 DOI: 10.1093/genetics/155.3.1055] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In this report, we investigated the phenotypes caused by temperature-sensitive (ts) mutant alleles of dna2(+) of Schizosaccharomyces pombe, a homologue of DNA2 of budding yeast, in an attempt to further define its function in vivo with respect to lagging-strand synthesis during the S-phase of the cell cycle. At the restrictive temperature, dna2 (ts) cells arrested at late S-phase but were unaffected in bulk DNA synthesis. Moreover, they exhibited aberrant mitosis when combined with checkpoint mutations, in keeping with a role for Dna2 in Okazaki fragment maturation. Similarly, spores in which dna2(+) was disrupted duplicated their DNA content during germination and also arrested at late S-phase. Inactivation of dna2(+) led to chromosome fragmentation strikingly similar to that seen when cdc17(+), the DNA ligase I gene, is inactivated. The temperature-dependent lethality of dna2 (ts) mutants was suppressed by overexpression of genes encoding subunits of polymerase delta (cdc1(+) and cdc27(+)), DNA ligase I (cdc17(+)), and Fen-1 (rad2(+)). Each of these gene products plays a role in the elongation or maturation of Okazaki fragments. Moreover, they all interacted with S. pombe Dna2 in a yeast two-hybrid assay, albeit to different extents. On the basis of these results, we conclude that dna2(+) plays a direct role in the Okazaki fragment elongation and maturation. We propose that dna2(+) acts as a central protein to form a complex with other proteins required to coordinate the multienzyme process for Okazaki fragment elongation and maturation.
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Affiliation(s)
- H Y Kang
- National Creative Research Initiative Center for Cell Cycle Control, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Changan-Ku Suwon, Kyunggi-Do, 440-746, Korea
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Choi D, Park JA, Seo YS, Chun YJ, Kim WT. Structure and stress-related expression of two cDNAs encoding proteinase inhibitor II of Nicotiana glutinosa L. Biochim Biophys Acta 2000; 1492:211-5. [PMID: 11004491 DOI: 10.1016/s0167-4781(00)00073-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Two cDNAs, pNGPI-1 and pNGPI-2, encoding Nicotiana glutinosa proteinase inhibitor II (PI-II) have been cloned, sequenced and identified. The deduced amino acid sequences are 54-82% identical to those of other plant PI-II. The NGPI-1 protein is composed of eight repeated domains, while NGPI-2 contains six repeated regions, each with a putative reactive site. The expression of NGPI-1 is highly regulated in a developmental- and tissue-specific manner, with the transcript being detected in young leaves and floral organs of N. glutinosa plants. In mature leaves, the NGPI-1 gene is rapidly activated by distinct temporal induction patterns in response to pathogen-related (biotic) and wound-related (abiotic) stresses.
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Affiliation(s)
- D Choi
- Plant Cell Biotechnology Laboratory, Korea Research Institute of Bioscience and Biotechnology, Taejeon, South Korea
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38
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Suk K, Kim S, Kim YH, Oh SH, Lee MK, Kim KW, Kim HD, Seo YS. Identification of a novel human member of the DEAD box protein family. Biochim Biophys Acta 2000; 1501:63-9. [PMID: 10727850 DOI: 10.1016/s0925-4439(00)00010-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The cDNA library of human pancreatic islets was screened with sera from patients with insulin-dependent diabetes mellitus (IDDM). From the library screening, we isolated a novel cDNA, RNA helicase-like protein (RHELP), which exhibited strong sequence homology to p68 RNA helicase, a prototypic member of the DEAD (Asp-Glu-Ala-Asp) box protein family. Sequence analysis of the cDNA revealed that RHELP contained DEAD sequence motif and other conserved motifs of the DEAD box protein family, indicating that RHELP is a new member of this family. DEAD box-containing proteins are involved in the RNA processing, ribosome assembly, spermatogenesis, embryogenesis, and cell growth and division. RHELP showed 42% and 44% amino acid sequence identity to human p68 RNA helicase and yeast DBP2 RNA helicase, respectively, among the DEAD box protein family. Northern blot analysis revealed that RHELP is expressed in most tissues including the liver, lung, tonsil, thymus, and muscle in addition to the pancreatic islets. In vivo or in vitro functions of RHELP as a putative RNA helicase and its potential role as a diabetic autoantigen need to be further investigated.
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Affiliation(s)
- K Suk
- Clinical Research Center, Samsung Biomedical Research Institute, Seoul, South Korea
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39
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Kim HD, Choe J, Seo YS. The sen1(+) gene of Schizosaccharomyces pombe, a homologue of budding yeast SEN1, encodes an RNA and DNA helicase. Biochemistry 1999; 38:14697-710. [PMID: 10545196 DOI: 10.1021/bi991470c] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two polynucleotide-dependent ATPases, 95 and 181 kDa in size, have been purified to near homogeneity from cell-free extracts of Schizosaccharomyces pombe. Despite their size differences, their biochemical properties were strikingly similar. Both enzymes were capable of unwinding RNA and DNA duplexes in keeping with their ability to hydrolyze ATP in the presence of either ribo- or deoxyribopolynucleotide. In addition, they were capable of unwinding DNA/RNA or RNA/DNA hybrid duplexes and translocated in the 5' to 3' direction. These results strongly indicate that they are closely related to each other. Determination of the partial amino acid sequence of the 95-kDa enzyme revealed that it is encoded by the sen1(+)() gene, an S. pombe homologue of yeast SEN1, a protein essential for the processing of small nucleolar RNA, transfer RNA, and ribosomal RNA. The molecular weight of the S. pombe Sen1 protein (SpSen1p) predicted from the sen1(+)() open reading frame was 192.5 kDa, suggesting that the 181-kDa enzyme is likely to be a full-length protein, whereas the 95-kDa polypeptide has arisen by proteolysis. In accord with this possibility, polyclonal antibodies specific to the C-terminal region of sen1(+)() cross-reacted with both 95- and 181-kDa polypeptides. We discuss the biochemical activities associated with SpSen1p and their relevance to the apparently divergent functions ascribed to the yeast Sen1 protein in RNA metabolism.
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Affiliation(s)
- H D Kim
- Center for Cell Cycle Control, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 300 Chunchun-dong, Jangan-gu, Suwon, Kyounggi, 440-746, Korea
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40
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Bae SH, Choi E, Lee KH, Park JS, Lee SH, Seo YS. Dna2 of Saccharomyces cerevisiae possesses a single-stranded DNA-specific endonuclease activity that is able to act on double-stranded DNA in the presence of ATP. J Biol Chem 1998; 273:26880-90. [PMID: 9756935 DOI: 10.1074/jbc.273.41.26880] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To gain further insights into the biological functions of Dna2, previously known as a cellular replicative helicase in Saccharomyces cerevisiae, we examined biochemical properties of the recombinant Dna2 protein purified to homogeneity. Besides the single-stranded (ss) DNA-dependent ATPase activity as reported previously, we were able to demonstrate that ssDNA-specific endonuclease activity is intrinsically associated with Dna2. Moreover, Dna2 was capable of degrading duplex DNA in an ATP-dependent fashion. ATP and dATP, the only nucleotides hydrolyzed by Dna2, served to stimulate Dna2 to utilize duplex DNA, indicating their hydrolysis is required. Dna2 was able to unwind short duplex only under the condition where the endonuclease activity was minimized. This finding implies that Dna2 unwinds only partially the 3'-end of duplex DNA and generates a stretch of ssDNA of limited length, which is subsequently cleaved by the ssDNA-specific endonuclease activity. A point mutation at the conserved ATP-binding site of Dna2 inactivated concurrently ssDNA-dependent ATPase, ATP-dependent nuclease, and helicase activities, indicating that they all reside in Dna2 itself. By virtue of its nucleolytic activities, the Dna2 protein may function in the maintenance of chromosomal integrity, such as repair or other related process, rather than in propagation of cellular replication forks.
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Affiliation(s)
- S H Bae
- Nucleic Acid Biochemistry Laboratory, Basic Research Center, Samsung Biomedical Research Institute, 50 Ilwon-Dong, Kangnam-Ku, Seoul 135-230, Korea
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41
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Lee C, Seo YS. Isolation and characterization of a processive DNA helicase from the fission yeast Schizosaccharomyces pombe that translocates in a 5'-to-3' direction. Biochem J 1998; 334 ( Pt 2):377-86. [PMID: 9716495 PMCID: PMC1219699 DOI: 10.1042/bj3340377] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We report here the isolation and characterization of a novel DNA helicase from extracts of the fission yeast Schizosaccharomyces pombe. The enzyme, called DNA helicase II, also contains an intrinsic DNA-dependent ATPase activity. Both the helicase and ATPase activities co-purified with a 63 kDa polypeptide on an SDS/polyacrylamide gel. The protein has a sedimentation coefficient of 4.8 S and a Stokes radius of 36 A (3.6 nm); from these data the native molecular mass was calculated to be 65 kDa. The enzyme translocates in a 5'-to-3' direction with respect to the substrate strand to which it is bound. Unwinding reactions carried out in the presence of increasing enzyme showed a sigmoidal curve, suggesting either co-operative interactions between monomers or multimerization of DNA helicase II in the presence of single-stranded DNA and/or ATP. This enzyme favoured adenosine nucleotides (ATP and dATP) as its energy source, but utilized to limited extents GTP, CTP, dGTP and dCTP. Non-hydrolysable ATP analogues did not support helicase activity. Kinetic analyses showed that the unwinding reaction was rapid, being complete after 50-100 s of incubation. Addition of unlabelled substrates to the helicase reaction after preincubation of the enzyme with substrate did not significantly diminish unwinding. The ATPase activity of DNA helicase II increased proportionally with increasing lengths of single-stranded DNA cofactor. In the presence of circular DNA, ATP hydrolysis continued to increase up to the longest time tested (3 h), whereas it ceased to increase after 5-10 min in the presence of shorter oligonucleotides. The initial rate of ATP hydrolysis during the first 5 min of incubation time was not affected by DNA species used. These data indicate that the enzyme does not dissociate from the single-stranded DNA once it is bound and is therefore highly processive.
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Affiliation(s)
- C Lee
- Nucleic Acid Biochemistry Laboratory, Basic Research Center, Samsung Biomedical Research Institute, 50 Ilwon-Dong, Kangnam-Ku, Seoul, 135-230, Korea
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42
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Petrov AP, Maximov VV, Maximov PV, Orlov OY, Kim CY, Seo YS. A Method for Measuring Apparent Illumination. Perception 1997. [DOI: 10.1068/v970345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Knowledge of perceived illumination is very important for almost all experimental investigations in colour science. We consider here a method for measuring apparent illumination based on the perceptual phenomenon of fluorescence. The underlying hypothesis is that the minimal illumination level at which a patch begins to look fluorescent exactly corresponds to the respective chromatic component of the apparent illumination in the scene. We report results of three experimental studies: (1) measurements of apparent illumination for a flat mondrian presented on a screen and mondrians made of paper presented in a specially designed box with controlled illumination observed monocularly; (2) measurements of apparent illumination in a ‘rich’ 3-D scene; (3) measurements to test the linearity of the subjective illumination space. The results confirm the basic hypothesis of the relation between fluorescence phenomena and perceived illumination and demonstrate that the proposed method gives reliable and accurate values for each of its chromatic components (errors were in the range 4% – 10%), eg for paper mondrians there was a strong correlation between the level and colour of illumination and the fluorescence. In the case of mondrians presented on a screen in darkness the measured apparent illumination was found unstable, however, as would be expected given that the context of such a scene is insufficient for a unique solution of the photometric problem. In the second experiment we found that the measurement results remain constant when the context of a ‘rich’ 3-D scene is changed and that they follow the changes in illumination conditions. In the third experiment we found that the linear relation f = f1+ f2 holds for the measured apparent illumination ( f) produced by combining of two other apparent illuminations ( f1, f2).
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Park JS, Choi E, Lee SH, Lee C, Seo YS. A DNA helicase from Schizosaccharomyces pombe stimulated by single-stranded DNA-binding protein at low ATP concentration. J Biol Chem 1997; 272:18910-9. [PMID: 9228070 DOI: 10.1074/jbc.272.30.18910] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A DNA helicase named DNA helicase I was isolated from cell-free extracts of the fission yeast Schizosaccharomyces pombe. Both DNA helicase and single-stranded DNA-dependent ATPase activities copurified with a polypeptide of 95 kDa on an SDS-polyacrylamide gel. The helicase possessed a sedimentation coefficient of 6.0 S and a Stokes radius of 44.8 A determined by glycerol gradient centrifugation and gel filtration analysis, respectively. From these data the native molecular mass was calculated to be 110 kDa, indicating that the active enzyme is a monomer. The DNA-unwinding and ATP hydrolysis activities associated with DNA helicase I have been examined. One notable property of the enzyme was its relatively high rate of ATP turnover (35-50 molecules of ATP hydrolyzed/s/enzyme molecule) that may contribute to its inefficient unwinding activity at low concentrations of ATP (<0.2 mM). Addition of an ATP-regenerating system to the reaction mixture restored the DNA-unwinding activity of the enzyme. S. pombe single-stranded DNA-binding protein (SpSSB, also called SpRPA) stimulated the DNA helicase activity significantly at low levels of ATP (0.025-0.2 mM) even in the absence of an ATP-regenerating system. In contrast, SpRPA had no effect on ATP hydrolysis at any ATP concentration examined. These observations suggest that the stimulation of DNA unwinding by SpRPA is not simply a result of suppression of nonproductive ATP hydrolysis. Rather, the role of SpRPA is to lower the Km for ATP in the unwinding reaction, allowing the helicase to function efficiently at low ATP concentrations.
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Affiliation(s)
- J S Park
- Basic Research Center, Nucleic Acid Biochemistry, Samsung Biomedical Research Institute, 50 Ilwon-Dong, Kangnam-Ku, Seoul 135-230, Korea
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44
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Lusky M, Hurwitz J, Seo YS. The bovine papillomavirus E2 protein modulates the assembly of but is not stably maintained in a replication-competent multimeric E1-replication origin complex. Proc Natl Acad Sci U S A 1994; 91:8895-9. [PMID: 8090740 PMCID: PMC44713 DOI: 10.1073/pnas.91.19.8895] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Initiation of bovine papillomavirus (BPV) DNA synthesis in vivo and in vitro depends on the interaction of the viral initiator protein E1 with the replication origin (ori+ DNA). The viral E2 protein assists this interaction, resulting in a cooperative assembly of both proteins on the replication origin. Using gel mobility-shift experiments, we demonstrate that in the presence of both E1 and E2 proteins two classes of ori+ DNA complexes were formed: complex 1 (c1) and complex 2 (c2). Formation of c1 depended on both the E1 and E2 proteins and both proteins were contained within c1. The generation of c2 was dependent on the E1 protein and could be enhanced by E2, but the E2 protein was not detected within c2. At high E2/E1 ratios, c1 was the dominant complex formed. Under these conditions, E1-dependent BPV DNA synthesis in vitro was inhibited. At low E2/E1 ratios, the stimulation of c2 was correlated with the stimulation of BPV DNA replication by E2 in vitro. These data suggest that E2 assists E1 in the formation of an intermediate c1 complex, which is replication inactive. The c1 complex is converted in turn to the replication-active c2 complex, which contains E1 but lacks E2. We propose that the ratios of c1 and c2 formed in response to the levels of E1 and E2 protein determine the potential for BPV DNA synthesis in vitro and in vivo and may contribute to copy number regulation of BPV plasmids within the cell.
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Affiliation(s)
- M Lusky
- Hearst Microbiology Research Center, Department of Microbiology, Cornell University Graduate School of Medical Sciences, New York, NY 10021
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45
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Müller F, Seo YS, Hurwitz J. Replication of bovine papillomavirus type 1 origin-containing DNA in crude extracts and with purified proteins. J Biol Chem 1994; 269:17086-94. [PMID: 8006013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The in vitro replication of DNA containing the bovine papillomavirus (BPV-1) origin has been carried out with cell-free extracts from mouse FM3A and human HeLa cells. DNA synthesis required the E1 protein, the minimal origin of replication (nucleotides 7911-22 of the BPV-1 genome), and, at low levels of FM3A extract, the addition of the human single-stranded DNA-binding protein (also called RP-A or RF-A). The E2 protein was not absolutely required, but could stimulate DNA synthesis at low levels of E1. DNA synthesis was also reconstituted using purified proteins from HeLa cells. These protein factors included human single-stranded DNA-binding protein, topoisomerase I, and DNA polymerase (pol) alpha-primase complex. At low concentrations of pol alpha-primase complex, the formation of high molecular weight products was dependent on the addition of DNA polymerase delta holoenzyme containing proliferating cell nuclear antigen and activator 1, also called RF-C. We have overexpressed and isolated the E1 protein from bacteria. This protein also supported BPV DNA synthesis, both in crude extracts and with purified proteins suggesting that E1 phosphorylation is not required for BPV DNA replication in vitro.
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Affiliation(s)
- F Müller
- Graduate Program in Molecular Biology, Memorial Sloan-Kettering Cancer Center, Sloan-Kettering Institute, New York, New York 10021
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46
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Lusky M, Hurwitz J, Seo YS. Cooperative assembly of the bovine papilloma virus E1 and E2 proteins on the replication origin requires an intact E2 binding site. J Biol Chem 1993; 268:15795-803. [PMID: 8393453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Using quantitative gel retardation assays the properties of the bovine papilloma virus (BPV) origin recognition protein E1 and the effect of the viral E2 protein on the binding of E1 to BPV origin DNA were examined. As reported previously (Seo, Y.S., Mueller, F., Lusky, M., Gibbs, E., Kim, H.-Y., Phillips, B. and J. Hurwitz (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 2865-2869), the E1 protein binds specifically to DNA sequences within the BPV origin (ori+) of replication. We also show that the presence of MgCl2 and ATP could stabilize the E1 ori+ DNA complex. At low levels of E1, ori+ DNA binding was greatly stimulated by the viral E2 protein when the intact E2 binding site 12 was present on the DNA. In addition DNA-protein complexes formed in the presence of both E1 and E2 were more stable than those formed with E1 alone. In the absence of an E2 binding site the E2 protein inhibited the binding of E1 to the BPV origin. Spacing of 0 or 9 base pairs between the E1 binding site and the E2 binding site 12 abolished the stimulation of E1-DNA binding by E2, whereas spacing of 6 base pairs between the two binding sites allowed for efficient stimulation. The data presented account for a direct role of E2 in BPV DNA replication. We propose that the cooperative binding of both the E1 and E2 proteins to BPV ori+ DNA is mediated by protein-protein interactions and by protein-DNA interactions, which include the formation of specific contacts of E2 with DNA.
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Affiliation(s)
- M Lusky
- Cornell University Graduate School of Medical Sciences, Hearst Microbiology Research Center, Department of Microbiology New York, New York 10021
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47
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Seo YS, Hurwitz J. Isolation of helicase alpha, a DNA helicase from HeLa cells stimulated by a fork structure and signal-stranded DNA-binding proteins. J Biol Chem 1993; 268:10282-95. [PMID: 8387516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
A DNA helicase, called DNA helicase alpha, was purified from HeLa cells to apparent homogeneity. The helicase and its single-stranded DNA-dependent ATPase activities cosedimented in glycerol gradients with two polypeptides of 110 and 90 kDa with a sedimentation coefficient of 7.4 S. The DNA helicase was markedly stimulated by DNA substrates with a 5'-tailed fork. A DNA substrate with a 3'-tailed fork structure was less stimulatory, although it was more active than substrates without a fork. The directionality of unwinding is 3'-->5' with respect to the single-stranded DNA to which the enzyme was bound. The helicase activity also required a single-stranded DNA-binding protein (SSB) for unwinding activity. The stimulation by SSBs was nonspecific; all SSBs tested, such as human SSB, bacteriophage T4 gene 32, and Escherichia coli SSB, stimulated the DNA helicase activity to a varying extent in the presence of a fork structure. With long duplex substrates (> 500 base pairs), the presence of a fork substantially stimulated the DNA helicase activity in the presence of E. coli SSB. Human SSB stimulated the DNA helicase activity to the greatest extent (> 10-fold) with a substrate containing a fork compared with substrates without a fork. DNA helicase activity required ATP hydrolysis and could be supported by all eight nucleoside triphosphates. The Km values for ATP and dATP in unwinding were 28 and 48 microM, respectively. In general, ribonucleoside triphosphates were better effectors than deoxyribonucleoside triphosphates. The properties of this DNA helicase make it a candidate for a DNA replicative helicase in human cells.
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Affiliation(s)
- Y S Seo
- Graduate Program in Molecular Biology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10021
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48
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Seo YS, Müller F, Lusky M, Gibbs E, Kim HY, Phillips B, Hurwitz J. Bovine papilloma virus (BPV)-encoded E2 protein enhances binding of E1 protein to the BPV replication origin. Proc Natl Acad Sci U S A 1993; 90:2865-9. [PMID: 8385347 PMCID: PMC46197 DOI: 10.1073/pnas.90.7.2865] [Citation(s) in RCA: 137] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The replication of bovine papilloma virus (BPV) DNA in vivo requires two viral-encoded proteins, E1 and E2, while all other proteins are derived from the host. We described previously the isolation of the E1 protein and showed that it contains multiple functions required for BPV DNA replication. The BPV transcription factor E2 was shown by others to stimulate BPV DNA replication in vitro. Here, we present results that account for the role of the E2 protein. The E1 protein bound selectively to the BPV minimal origin of replication. This process required MgCl2 and ATP for maximal efficiency. The E1 protein also catalyzed a BPV origin-dependent DNA unwinding reaction. In this report, we show that at low levels of E1 protein, origin binding could be stimulated up to 40-fold by the E2 protein, provided that the DNA contained an E2 binding site. Consistent with this result, the E2 protein stimulated the origin-specific unwinding reaction catalyzed by E1, but it had no effect on the nonspecific E1-catalyzed helicase activity. In the absence of an E2 binding site, both origin-dependent binding and unwinding reactions with the E1 protein were unaffected by the E2 protein. These results suggest that E2 participates in the initiation of BPV DNA replication by enhancing E1 binding to the BPV origin via DNA-protein and protein-protein interactions.
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Affiliation(s)
- Y S Seo
- Graduate Program in Molecular Biology, Sloan-Kettering Cancer Center, New York, NY 10021
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49
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Seo YS, Müller F, Lusky M, Hurwitz J. Bovine papilloma virus (BPV)-encoded E1 protein contains multiple activities required for BPV DNA replication. Proc Natl Acad Sci U S A 1993; 90:702-6. [PMID: 8380645 PMCID: PMC45733 DOI: 10.1073/pnas.90.2.702] [Citation(s) in RCA: 156] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Replication of bovine papilloma virus (BPV) DNA requires two virus-encoded proteins, E1 and E2, while all other proteins are supplied by the host cell. Here, we describe the isolation of the E1 protein and show that it is a multifunctional protein. Purified E1 protein was required for the in vitro replication of BPV origin-containing DNA by extracts of mouse cells, as reported [Yang, L., Li, R., Mohr, I. J., Clark, R. & Botchan, M. R. (1991) Nature (London) 353, 628-632]. In addition, the E1 protein cosedimented with a number of other activities including (i) DNA helicase activity, (ii) BPV origin-containing DNA-specific binding activity, (iii) DNA-dependent ATPase activity, and (iv) BPV origin-specific unwinding of superhelical DNA. The E1 protein, acting as a helicase, moved in the 3'-->5' direction, like simian virus 40 (SV40) large tumor antigen, which plays a pivotal role in SV40 DNA replication. However, unlike the SV40 large tumor antigen, the helicase activity of E1 was stimulated 5-fold by the presence of a fork structure at the junction between single-stranded and double-stranded DNA and was supported efficiently by all eight nucleoside triphosphates. The E1-catalyzed ATPase activity required the presence of single-stranded or double-stranded DNAs.
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Affiliation(s)
- Y S Seo
- Graduate Program in Molecular Biology, Sloan-Kettering Cancer Center, New York, NY 10021
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Seo YS, Lee SH, Hurwitz J. Isolation of a DNA helicase from HeLa cells requiring the multisubunit human single-stranded DNA-binding protein for activity. J Biol Chem 1991; 266:13161-70. [PMID: 1649181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A DNA helicase, dependent on the multisubunit human single-stranded DNA binding protein (HSSB), was isolated from HeLa cells. At low levels of helicase, only the multisubunit SSBs, HSSB and yeast SSB, stimulated DNA helicase activity. At high levels of the helicase Escherichia coli SSB partially substituted for HSSB whereas other SSBs such as T4 gene 32 and adenovirus DNA binding protein did not stimulate the enzyme activity. Maximal activation of helicase activity occurred in the presence of one molecule of HSSB for every 20 nucleotides of single-stranded DNA. The addition of E. coli SSB significantly lowered the amount of HSSB required for strand displacement, suggesting that the HSSB plays at least two roles in the activation of the helicase. One is to bind single-stranded DNA, thereby preventing sequestration of the helicase, the other involves the interaction of the HSSB with the helicase. Monoclonal antibodies that interact with the 70- and 34-kDa subunits of HSSB inhibited its stimulation of the helicase activity. The DNA helicase acted catalytically in displacing duplex DNA and translocated in the 3' to 5' direction. The helicase displaced fragments from both ends of a DNA substrate that contained duplex region at both termini, but the 3' to 5' fragment was displaced 20 times faster than the 5' to 3' fragment. Since this helicase also displaced fully duplex DNA, the release of the 5' to 3' fragment may have occurred by entry of the helicase through the duplex end in a 3' to 5' direction.
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Affiliation(s)
- Y S Seo
- Graduate Program in Molecular Biology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021
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