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Chang J, Suh T, Lee D, Cho G. SU-FF-I-104: Development of a Deformable Lung Phantom for the Evaluation of Deformable Registration. Med Phys 2009. [DOI: 10.1118/1.3181225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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52
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Morales J, Cho G. SU-FF-T-213: Evaluation of RadCalc V5.2 as An Independent Monitor Unit Checking Program for Dynamic IMRT Plans. Med Phys 2009. [DOI: 10.1118/1.3181688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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53
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Choi Y, Song M, Seol Y, Kwon B, Shin H, Chung J, Lee J, Lee B, Kim S, Sohn C, Cho G. Use of tumor volume as measured on F18FDG-PET/CT scan as a predictive biomarker for head and neck cancer. J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.e17019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e17019 Background: Functional imaging, PET and its fusion with anatomical modalities, PET/CT promise to improve detection and characteristic disease. The objective of this study was to evaluate metabolic tumor volume as measured on F-18 FDG-PET/CT and its association with treatment response and prognosis in patients with head and neck cancer. Methods: The study population consisted of patients received neoadjuvant chemotherapy for a maximum of three cycles followed by radiation therapy. Before treatment patients were taken FDG-PET/CT scan, SUVmax, tumor volume, metastasis were recorded. Results: We enrolled 59 patients with stage III ann IV head and neck cancer. The median age was 66 years (range 47–81). There were 32 patients with stage III and 27 with stage IV. The mean SUVmax was 8.8 (range, 1.478). The mean tumor volume was 21.3 cm3 (range, 0.2–170). There was no correlation between tumor volume and SUVmax (correlation coefficient 0.295). Higher SUVmax was not associated with an increased risk of lymph node and distant metastasis at diagnosis (p = 0.968). But higher tumor volume was associated with an increased risk of lymph node and distant metastasis at diagnosis (p = 0.063). The metabolic tumor volume as measured on PET/CT scans was predictor of treatment response and disease -free survival. The response rate were 84% (21/25) for an SUVmax <5.5, 55% (19/34) for an SUVmax > 5.5 (p = 0.038). The disease free survival were 31.1month for an SUVmax <5.5, 4.6months for an SUVmax > 5.5 (p = 0.025). Conclusions: The metabolic tumor volume as measured on F-18FDG-PET/CT is a predictive biomarker of treatment response and disease free survival for patients with head and neck cancer. No significant financial relationships to disclose.
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Kulendra K, Butler C, Grant W, Sandison A, Cho G, Patel M. An Unusual Lesion of the Clivus. Skull Base 2009. [DOI: 10.1055/s-2009-1222375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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55
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Pan Y, Iwata F, Wang D, Muraguchi M, Ooga K, Ohmoto Y, Takai M, Cho G, Kang J, Shono M, Li XJ, Okamura K, Mori T, Ishikawa Y. Identification of aquaporin-5 and lipid rafts in human resting saliva and their release into cevimeline-stimulated saliva. Biochim Biophys Acta Gen Subj 2009; 1790:49-56. [DOI: 10.1016/j.bbagen.2008.08.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2007] [Revised: 08/22/2008] [Accepted: 08/25/2008] [Indexed: 12/20/2022]
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Marquardt B, Eude L, Gowtham M, Cho G, Jeong HJ, Châtelet M, Cojocaru CS, Kim BS, Pribat D. Density control of electrodeposited Ni nanoparticles/nanowires inside porous anodic alumina templates by an exponential anodization voltage decrease. NANOTECHNOLOGY 2008; 19:405607. [PMID: 21832627 DOI: 10.1088/0957-4484/19/40/405607] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Porous alumina templates have been fabricated by applying an exponential voltage decrease at the end of the anodization process. The time constant η of the exponential voltage function has been used to control the average thickness and the thickness distribution of the barrier layer at the bottom of the pores of the alumina structure. Depending on the η value, the thickness distribution of the barrier layer can be made very uniform or highly scattered, which allows us to subsequently fine tune the electrodeposition yield of nickel nanoparticles/nanowires at low voltage. As an illustration, the pore filling percentage with Ni has been varied, in a totally reproducible manner, between ∼3 and 100%. Combined with the ability to vary the pore diameter and repetition step over ∼2 orders of magnitude (by varying the anodization voltage and electrolyte type), the control of the pore filling percentage with metal particles/nanowires could bring novel approaches for the organization of nano-objects.
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Choi Y, Chung J, Shin H, Cho G, Sohn C. Dendritic cell immunotherapy in non-small cell lung cancer. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.14013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Kim H, Hyung W, Cho G, Kim M, Han S, Kim W, Ryu S, Lee H, Song K. Comparison of laparoscopic versus open gastrectomy for gastric cancer: a phase III trial (KLASS trial): Interim reports on morbidity and mortality. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.4641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Martos P, Rubio P, Mancha M, González R, Escorial V, Cho G, González FD. O.416 Protocol for surgicaly assisted maxillary expansion. J Craniomaxillofac Surg 2006. [DOI: 10.1016/s1010-5182(06)60438-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Ishikawa Y, Cho G, Yuan Z, Skowronski MT, Pan Y, Ishida H. Water channels and zymogen granules in salivary glands. J Pharmacol Sci 2006; 100:495-512. [PMID: 16799262 DOI: 10.1254/jphs.crj06007x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Salivary secretion occurs in response to stimulation by neurotransmitters released from autonomic nerve endings. The molecular mechanisms underlying the secretion of water, a main component of saliva, from salivary glands are not known; the plasma membrane is a major barrier to water transport. A 28-kDa integral membrane protein, distributed in highly water-permeable tissues, was identified as a water channel protein, aquaporin (AQP). Thirteen AQPs (AQP0 - AQP12) have been identified in mammals. AQP5 is localized in lipid rafts under unstimulated conditions and translocates to the apical plasma membrane in rat parotid glands upon stimulation by muscarinic agonists. The importance of increases in intracellular calcium concentration [Ca(2+)](i) and the nitric oxide synthase and protein kinase G signaling pathway in the translocation of AQP5 is reviewed in section I. Signals generated by the activation of Ca(2+) mobilizing receptors simultaneously trigger and regulate exocytosis. Zymogen granule exocytosis occurs under the control of essential process, stimulus-secretion coupling, in salivary glands. Ca(2+) signaling is a principal signal in both protein and water secretion from salivary glands induced by cholinergic stimulation. On the other hand, the cyclic adenosine monophosphate (cAMP)/cAMP-dependent protein kinase system has a major role in zymogen granule exocytosis without significant increases in [Ca(2+)](i). In section II, the mechanisms underlying the control of salivary protein secretion and its dysfunction are reviewed.
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Baek J, Kim J, Chae Y, Cho Y, Sohn S, Choi Y, Shin H, Chung J, Cho G, Yu W. Phase II study of capecitabine and irinotecan combination chemotherapy in patients with advanced gastric cancer. J Clin Oncol 2006. [DOI: 10.1200/jco.2006.24.18_suppl.14037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
14037 Background: Several studies have shown the efficacy of capecitabine and irinotecan combination chemotherapy for advanced colorectal cancer, while no results have yet been reported for advanced gastric cancer. Accordingly, the current study evaluated the efficacy and safety of a combination regimen of capecitabine plus irinotecan in patients with advanced gastric cancer. Methods: Patients with previously untreated metastatic or recurrent, measurable gastric cancer received oral capecitabine 1000 mg/m2 twice daily from day 1 to 14 and intravenous irinotecan 100 mg/m2 on days 1 and 8, based on a 3-week cycle. Results: Forty-one patients were enrolled in the current study, among whom 38 were assessable for efficacy and 40 assessable for toxicity. Three complete responses and 16 partial responses were confirmed, giving an overall response rate of 46.3%. At a median follow-up of 269 days, the median time to progression and overall survival were 5.1 months and 8.6 months, respectively. Grade 3/4 neutropenia occurred in 4 patients and grade 3 febrile neutropenia was observed in 2 patients. Grade 3 diarrhea and grade 2 hand-foot syndrome occurred in 6 patients and 8 patients, respectively. Conclusions: The combination of capecitabine and irinotecan was found to be well tolerated and effective in patients with advanced gastric cancer. Accordingly, this regimen can be regarded as an important first-line treatment option for advanced gastric cancer. No significant financial relationships to disclose.
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Ishikawa Y, Cho G, Yuan Z, Inoue N, Nakae Y. Aquaporin-5 water channel in lipid rafts of rat parotid glands. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1053-60. [PMID: 16712780 DOI: 10.1016/j.bbamem.2006.03.026] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Revised: 03/02/2006] [Accepted: 03/21/2006] [Indexed: 01/26/2023]
Abstract
Aquaporin-5 (AQP5), an apical plasma membrane (APM) water channel in salivary glands, lacrimal glands, and airway epithelium, has an important role in fluid secretion. The activation of M3 muscarinic acetylcholine receptors (mAChRs) or alpha1-adrenoceptors on the salivary glands induces salivary fluid secretion. AQP5 localizes in lipid rafts and activation of the M3 mAChRs or alpha1-adrenoceptors induced its translocation together with the lipid rafts to the APM in the interlobular ducts of rat parotid glands. This review focuses on the mechanisms of AQP5 translocation together with lipid rafts to the APM in the interlobular duct cells of parotid glands of normal rats and the impairment of AQP5 translocation in diabetes and senescence.
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Cho G, Nakae Y, Ishikawa Y. [The mechanisms that underlie xerostomia and the translocation of aquaporin]. Nihon Yakurigaku Zasshi 2006; 127:267-72. [PMID: 16755078 DOI: 10.1254/fpj.127.267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
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Ishikawa Y, Yuan Z, Inoue N, Skowronski MT, Nakae Y, Shono M, Cho G, Yasui M, Agre P, Nielsen S. Identification of AQP5 in lipid rafts and its translocation to apical membranes by activation of M3 mAChRs in interlobular ducts of rat parotid gland. Am J Physiol Cell Physiol 2005; 289:C1303-11. [PMID: 16107506 DOI: 10.1152/ajpcell.00211.2005] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aquaporin-5 (AQP5), an apical plasma membrane (APM) water channel in salivary glands, lacrimal glands, and airway epithelium, has an important role in fluid secretion. M(3) muscarinic acetylcholine receptor (mAChR)-induced changes in AQP5 localization in rat parotid glands were investigated with immunofluorescence or immunoelectron microscopy, detergent solubility, and gradient density floatation assays. Confocal microscopy revealed AQP5 localization in intracellular vesicles of interlobular duct cells in rat parotid glands and AQP5 trafficking to the APM 10 min after injection of the mAChR agonist cevimeline. Conversely, 60 min after injection, there was a diffuse pattern of AQP5 staining in the cell cytoplasm. The calcium ionophore A-23187 mimicked the effects of cevimeline. Immunoelectron microscopic studies confirmed that cevimeline induced AQP5 trafficking from intracellular structures to APMs in the interlobular duct cells of rat parotid glands. Lipid raft markers flotillin-2 and GM1 colocalized with AQP5 and moved with AQP5 in response to cevimeline. Under control conditions, the majority of AQP5 localized in the Triton X-100-insoluble fraction and floated to the light-density fraction on discontinuous density gradients. After 10-min incubation of parotid tissue slices with cevimeline or A-23187, AQP5 levels decreased in the Triton X-100-insoluble fraction and increased in the Triton X-100-soluble fraction. Thus AQP5 localizes in the intracellular lipid rafts, and M(3) mAChR activation induces AQP5 trafficking to the APM with lipid rafts via intracellular Ca(2+) signaling and induces AQP5 dissociation from lipid rafts to nonrafts on the APM in the interlobular duct cells of rat parotid glands.
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Ohshita N, Takaishi K, Eguchi S, Cho G, Tomioka S, Nakajo N. [Anesthetic management of a teenage athlete who developed arrhythmia during general anesthesia]. MASUI. THE JAPANESE JOURNAL OF ANESTHESIOLOGY 2005; 54:676-9. [PMID: 15966390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A 17-year-old man with fracture of the mandible underwent open fixation under general anesthesia. He was an athlete of the rugby suffering the fracture in a match. His preoperative physical examinations were normal except for I degrees atrioventricular block on electrocardiogram (ECG). During anesthesia, atrioventricular dissociation and frequent premature ventricular contractions were induced by the stimulation of nasotracheal intubation and the administration of atropine for the reversal of muscle relaxation. We thought the cause of the arrhythmia is the athlete's heart which may be vagotonic and may induce vagal reflex or fatal arrhythmia. This case demonstrates that it is necessary to pay attention to chronotropic action associated with the intubation of nasopharynx, the handling of laryngoscope and the usage of drugs for the anesthetic management of the athlete.
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Kim BH, Chang SY, Lee HS, Cho G. Measurement of the neutron fluence and dose spectra using an extended bonner sphere and a tissue-equivalent proportional counter. RADIATION PROTECTION DOSIMETRY 2004; 110:717-723. [PMID: 15353737 DOI: 10.1093/rpd/nch182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A conventional Bonner Sphere (BS) set consisting of six polyethylene spheres was modified to enhance its response to a high-energy neutron by putting a lead shell inside a polyethylene moderator. The response matrix of an extended BS was calculated using the MCNPX code and calibrated using a 252Cf neutron source. In order to survey the unknown photon and neutron mixed field, a spherical tissue equivalent proportional counter (TEPC) was constructed and assembled as a portable measurement system. The extended BS and the self-constructed TEPC were employed to determine the dosimetric quantities of the neutron field produced from the thick lead target bombarded by the 2.5 GeV electron beam of Pohang Accelerator Laboratory (PAL) and the neutron calibration field of Korea Atomic Energy Research Institute (KAERI).
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Cho G. Preparation of polymer films with enhanced ion conductivity via 3-D controlled ionic nanochannels. Electrochem commun 2002. [DOI: 10.1016/s1388-2481(02)00312-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Kim C, Yeo S, Cho G, Lee J, Choi M, Won C, Kim J, Lee S. Polymelia with two extra forelimbs at the right scapular region in a male Korean native calf. J Vet Med Sci 2001; 63:1161-4. [PMID: 11714039 DOI: 10.1292/jvms.63.1161] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In a male Korean native calf 14 days of age, polymelia (notomelia) was observed macroscopically and radiographically. External features included two normal forelimbs, two normal hindlimbs and two undeveloped extra forelimbs. The extra forelimbs were attached to the caudal regions of the right scapula and devoid of muscular tissues. In the extra forelimbs, a scapula-like bone formed a joint with the incompletely duplicated humerus. The humerus fused with the incompletely duplicated radius. The ulna, carpal bones, metacarpal bones and phalanges were completely duplicated. But one set of the duplicated carpal bones consisted of five bones: radial, accessory, fourth carpal, fused second and third carpal, and fused ulnar and intermediate carpal bones. The hoof and the rudimentary hoof of accessory digit were duplicated.
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Cho G, Fung BM, Reddy VB. Phospholipid bicelles with positive anisotropy of the magnetic susceptibility. J Am Chem Soc 2001; 123:1537-8. [PMID: 11456744 DOI: 10.1021/ja005605+] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cho G, Suh SW, Jung G. HBV polymerase interacts independently with N-terminal and C-terminal fragments of Hsp90beta. Biochem Biophys Res Commun 2000; 274:203-11. [PMID: 10903919 DOI: 10.1006/bbrc.2000.3119] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hsp90 is an abundant chaperone protein that assists the folding of specific proteins, such as steroid receptors, protein kinases, and so on, for their proper function. TP and RT domains of HBV polymerase have been also shown to be associated with Hsp90. Therefore, the identification of the binding sites within Hsp90, responsible for forming Hsp90/HBV Pol complex, is important for the understanding of HBV replication. In this study, cotransfection and immunoprecipitation experiments were performed to localize the binding sites of HBV pol to Hsp90. Our data show that HBV pol interact independently with both N-terminal and C-terminal fragments of Hsp90. Further analysis showed that N-terminal fragment (1-302) of Hsp90 interacts with both TP and RT domains of HBV pol, whereas C-terminal fragment (438-723) interacts with only RT domain. In conclusion, we showed that HBV pol independently interacts with N-terminal and C-terminal fragments, but not the middle fragment (327-438) of Hsp90.
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Cho G, Keefe AD, Liu R, Wilson DS, Szostak JW. Constructing high complexity synthetic libraries of long ORFs using in vitro selection. J Mol Biol 2000; 297:309-19. [PMID: 10715203 DOI: 10.1006/jmbi.2000.3571] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We present a method that can significantly increase the complexity of protein libraries used for in vitro or in vivo protein selection experiments. Protein libraries are often encoded by chemically synthesized DNA, in which part of the open reading frame is randomized. There are, however, major obstacles associated with the chemical synthesis of long open reading frames, especially those containing random segments. Insertions and deletions that occur during chemical synthesis cause frameshifts, and stop codons in the random region will cause premature termination. These problems can together greatly reduce the number of full-length synthetic genes in the library. We describe a strategy in which smaller segments of the synthetic open reading frame are selected in vitro using mRNA display for the absence of frameshifts and stop codons. These smaller segments are then ligated together to form combinatorial libraries of long uninterrupted open reading frames. This process can increase the number of full-length open reading frames in libraries by up to two orders of magnitude, resulting in protein libraries with complexities of greater than 10(13). We have used this methodology to generate three types of displayed protein library: a completely random sequence library, a library of concatemerized oligopeptide cassettes with a propensity for forming amphipathic alpha-helical or beta-strand structures, and a library based on one of the most common enzymatic scaffolds, the alpha/beta (TIM) barrel.
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Cho G, Park SG, Jung G. Localization of HSP90 binding sites in the human hepatitis B virus polymerase. Biochem Biophys Res Commun 2000; 269:191-6. [PMID: 10694498 DOI: 10.1006/bbrc.2000.2240] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The fact that HSP90 proteins and their chaperonin partners play an important role in epsilon RNA binding of duck HBV Pol protein during duck HBV replication has been reported. To elucidate the molecular basis of HBV Pol/HSP90 interaction, we have characterized the HSP90 interaction to HBV Pol. We found that human HBV Pol protein upon synthesis in rabbit reticulocyte lysate formed a complex with HSP90 in vitro as duck HBV Pol did. In addition, HSP90 protein was copurified with MBP/POL protein expressed in HepG2 cells, suggesting that human HBV Pol protein is associated with HSP90 in vivo. To localize the HSP90 interaction site region, several deletion mutants of HBV Pol translated in vitro were immunoprecipitated with anti-HSP90 antibody. The result indicates that C-terminal regions of the TP and RT domains interact with HSP90 independently.
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Doolittle RF, Feng DF, Cho G. Determining divergence times with protein clocks. THE BIOLOGICAL BULLETIN 1999; 196:356-358. [PMID: 11536911 DOI: 10.2307/1542969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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74
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Seo SJ, Kang SS, Cho G, Rho HM, Jung G. C/EBP alpha and C/EBPbeta play similar roles in the transcription of the human Cu/Zn SOD gene. Gene 1997; 203:11-5. [PMID: 9426001 DOI: 10.1016/s0378-1119(97)00484-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Copper/zinc-containing superoxide dismutase (Cu/Zn SOD) is one of the essential enzymes that protects cells in aerobic conditions. To understand the mechanism of transcriptional regulation of the human Cu/Zn SOD gene, the proximal promoter region of Cu/Zn SOD has been investigated. In a previous study, it was found that transcription factors of the Sp1 and C/EBP family are associated with the expression of human Cu/Zn SOD [Seo et al. (1996). Gene, 178, 177-180]. Of the four known C/EBP activators, the effects of C/EBP alpha and C/EBPbeta on the transcription of Cu/Zn SOD were examined. Usually, one of the two C/EBP factors, C/EBP alpha or C/EBPbeta, exclusively stimulates the target gene, but, unexpectedly, C/EBP alpha and C/EBPbeta stimulated the expression of Cu/Zn SOD to a similar extent in our experiments. LIP, a dominant negative regulator of the C/EBP family, inhibited the transcriptional activation of Cu/Zn SOD stimulated by C/EBP alpha and C/EBPbeta. These results suggest that C/EBP alpha and C/EBPbeta can substitute each other and play similar roles on the transcription of Cu/Zn SOD.
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Feng DF, Cho G, Doolittle RF. Determining divergence times with a protein clock: update and reevaluation. Proc Natl Acad Sci U S A 1997; 94:13028-33. [PMID: 9371794 PMCID: PMC24257 DOI: 10.1073/pnas.94.24.13028] [Citation(s) in RCA: 325] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/1997] [Indexed: 02/05/2023] Open
Abstract
A recent study of the divergence times of the major groups of organisms as gauged by amino acid sequence comparison has been expanded and the data have been reanalyzed with a distance measure that corrects for both constraints on amino acid interchange and variation in substitution rate at different sites. Beyond that, the availability of complete genome sequences for several eubacteria and an archaebacterium has had a great impact on the interpretation of certain aspects of the data. Thus, the majority of the archaebacterial sequences are not consistent with currently accepted views of the Tree of Life which cluster the archaebacteria with eukaryotes. Instead, they are either outliers or mixed in with eubacterial orthologs. The simplest resolution of the problem is to postulate that many of these sequences were carried into eukaryotes by early eubacterial endosymbionts about 2 billion years ago, only very shortly after or even coincident with the divergence of eukaryotes and archaebacteria. The strong resemblances of these same enzymes among the major eubacterial groups suggest that the cyanobacteria and Gram-positive and Gram-negative eubacteria also diverged at about this same time, whereas the much greater differences between archaebacterial and eubacterial sequences indicate these two groups may have diverged between 3 and 4 billion years ago.
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