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Hye-Jin Lee

Publications and source records attributed to Hye-Jin Lee.

14 recordsLinked to original sources
PubMed2006

Alteration of Rb binding to HPV 18 E7 modified by transglutaminase 2 with different type of polyamines.

High-risk human papillomavirus (HPV) E7 is a major oncoprotein that plays a crucial role in the development of cervical cancer. A previous study showed that transglutaminase (TGase) 2 catalyzes the incorporation of polyamines into HPV 18 E7 protein, and thereby diminishes its ability to bind Rb. Therefore, TGase 2 activity may be implicated in a suppressive function of host against HPV-induced carcinogenesis. To better understand the nature of polyamination of HPV 18 E7, we investigated the Rb binding of E7 polyaminated in vitro with different type of polyamines. The incorporation of spermine diminished the Rb binding of E7 more profoundly compared with that of spermidine, suggesting that either the additional positive charge or a steric effect or both may have altered the chemical or structural properties of the protein. In addition, the treatment of either spermidine or spermine in cultured cell system reduced the ability of E7 to inactivate Rb with a TGase activity-dependent manner. Spermine was more effective in inhibiting E7 activity than spermidine. These results may provide the basis for future investigation aiming at delineating the significance of polyamine metabolism on HPV E7 functions.

Amines↗
PubMed2006

Enzymatic synthesis of sorbitan methacrylate according to acyl donors.

Recently, sugar polymers have been considered for use as biomaterials in medical applications. These biomaterials are already used extensively in burn dressings, artificial membranes, and contact lenses. In this study, we investigated the optimum conditions under which the enzymatic synthesis of sorbitan methacrylate can be affected using Novozym 435 in t-butanol from sorbitan and several acyl donors (ethyl methacrylate, methyl methacrylate, and vinyl methacrylate). The enzymatic synthesis of sorbitan methacrylate, catalyzed by Novozym 435 in t-butanol, reached an approx 68% conversion yield at 50 g/L of 1,4-sorbitan, 5% (w/v) of enzyme content, and a 1:5 molar ratio of sorbitan to ethyl methacrylate, with a reaction time of 36 h. Using methyl methacrylate as the acyl donor, we achieved a conversion yield of approx 78% at 50 g/L of 1,4-sorbitan, 7% (w/v) of enzyme content, at a 1:5 molar ratio, with a reaction time of 36 h. Sorbitan methacrylate synthesis using vinyl methacrylate as the acyl donor was expected to result in a superior conversion yield at 3% (w/v) of enzyme content, and at a molar ratio greater than 1:2.5. Higher molar ratios of acyl donor resulted in more rapid conversion rates. Vinyl methacrylate can be applied to obtain higher yields than are realized when using ethyl methacrylate or methyl methacrylate as acyl donors in esterification reactions catalyzed by Novozym 435 in organic solvents. Enzyme recycling resulted in a drastic reduction in conversion yields.

Acylation↗
PubMed2006

Molecular cloning of rHAUSP encoding a deubiquitinating enzyme in rat testis.

The tumor suppressor protein p53 is stabilized by the herpes-virus-associated ubiquitin-specific protease (HAUSP), a deubiquitinating enzyme. We previously isolated and characterized a mouse orthologue of HAUSP, mHAUSP. In this study, we have identified a rat orthologue of HAUSP, rHAUSP, from the rat testis by RT-PCR using primers used for cloning mHAUSP. rHAUSP cDNA encodes 3,312 bp and 1,103 amino acids with a molecular weight of approximately 135 kDa containing highly conserved Cys, Asp (I), His, and Asn/Asp (II) domains characteristic of the ubiquitin-specific processing proteases. pI value of rHAUSP is 5.31. In vivo and in vitro deubiquitinating enzyme assays demonstrated that rHAUSP has deubiquitinating enzymatic activity. The over-expression of rHAUSP induced cell death of cervical adenocarcinoma cells.

Amino Acid Sequence↗
PubMed2005

HAUSP, a deubiquitinating enzyme for p53, is polyubiquitinated, polyneddylated, and dimerized.

The tumor suppressor protein p53 is ubiquitinated and neddylated by MDM2 and then degraded by 26S proteasome. However, p53 is stabilized by the HAUSP (Herpes-virus-associated ubiquitin-specific protease) deubiquitinating enzyme. In this study, we discovered that rat HAUSP (rHAUSP) is polyubiquitinated, polyneddylated, and dimerized using co-immunoprecipitation assays. This suggests that rHAUSP may function as a dimer or multimer and is also degraded through the proteasome-mediated degradation. Transfection of rHAUSP into RGC-Lac-Z cell line with the integrated p53 response element revealed that rHAUSP contributed to p53 stabilization, and a rHAUSP (C224S) mutant contributed to p53 destabilization in a dose-dependent manner.

Animals↗
PubMed2005

Expression and functional analyses of mHAUSP regulating apoptosis of cervical adenocarcinoma cells.

p53 tumor suppressor protein is stabilized by the herpes-virus-associated ubiquitin-specific protease (HAUSP), a deubiquitinating enzyme. We previously isolated a mouse orthologue of HAUSP, mHAUSP, encoding 1103 amino acids with a molecular weight of approximately 135 kDa containing highly conserved Cys, Asp (I), His, and Asn/Asp (II) domains. In this study, we investigated the temporal and spatial expression of mHAUSP during the early mouse embryonic development. Northern blot analysis revealed that the expression of mHAUSP was detected throughout the process of embryonic development with the maximal expression between E10.5 and E13.5. In situ hybridization study showed the global expression of mHAUSP in various organs of embryos, including mesencephalon, spinal cord, lung and genital eminence. In addition, we carried out biochemical analysis for 6 conserved amino acids (Cys224, Gln231, Asp296, His457, His465, and Asp482) in Cys box, QQD box, and His box in order to investigate their structural and functional roles of these amino acid residues. The conserved Gln231 was not essential for the catalytic activity of mHAUSP. However, other conserved amino acids were required for deubiquitinating enzyme activity of mHAUSP. Moreover, we observed that the overexpression of mHAUSP induces cell death in HeLa cells.

Amino Acid Sequence↗
PubMed2004

Different inhibition characteristics of intracellular transglutaminase activity by cystamine and cysteamine.

The treatment of cystamine, a transglutaminase(TGase) inhibitor, has beneficial effects in several diseases including CAG-expansion disorders and cataract. We compared the inhibition characteristics of cystamine with those of cysteamine, a reduced form of cystamine expect-ed to be present inside cells. Cystamine is a more potent inhibitor for TGase than cysteamine with different kinetics pattern in a non-reducing condition. By contrast, under reducing conditions, the inhibitory effect of cystamine was comparable with that of cysteamine. How-ever, cystamine inhibited intracellular TGase activity more strongly than cysteamine despite of cytoplasmic reducing environment, suggest-ing that cystamine itself inhibits in situ TGase activity by forming mixed disulfides.

Cell Line, Tumor↗
PubMed2004

Essential regions of deubiquitinating enzyme activity and enhancer function for DUB-2A expressed in T-lymphocytes.

Novel subfamily members of deubiquitinating enzyme gene, DUB-1 and DUB-2, are known to be immediate-early genes and are specifically expressed in B-lymphocytes and T-lymphocytes, respectively. Recently, another deubiquitinating enzyme gene DUB-2A, expressed also in T-lymphocytes, has been isolated and we, in this study, found that Dub-2A has isopeptidase activity and there are at least 4 conserved amino acids (Cys60, Asp133, His298, and His307) that are required for catalytic activity of the enzyme. Interestingly, the conserved Asp323 was not essential for the catalytic activity. In addition, transcriptional reporter assay showed that an Ets site and 2 AP-1 sites in the enhancer domain of this gene are required for cytokine inducibility. Taken all together, these results will be very helpful in designing activators or inhibitors of this enzyme in order to regulate its expression and catalytic activity in T-lymphocytes.

Amino Acid Sequence↗
PubMed2004

Cell type-specific activation of intracellular transglutaminase 2 by oxidative stress or ultraviolet irradiation: implications of transglutaminase 2 in age-related cataractogenesis.

Transglutaminase (TGase) 2 is a ubiquitously expressed enzyme that modifies proteins by cross-linking or polyamination. An aberrant activity of TGase 2 has implicated its possible roles in a variety of diseases including age-related cataracts. However, the molecular mechanism by which TGase 2 is activated has not been elucidated. In this report, we showed that oxidative stress or UV irradiation elevates in situ TGase 2 activity. Neither the expression level nor the in vitro activity of TGase 2 appeared to correlate with the observed elevation of in situ TGase 2 activity. Screening a number of cell lines revealed that the level of TGase 2 activation depends on the cell type and also the environmental stress, suggesting that unrecognized cellular factor(s) may specifically regulate in situ TGase 2 activity. Concomitantly, we observed that human lens epithelial cells (HLE-B3) exhibited about 3-fold increase in in situ TGase 2 activity in response to the stresses. The activated TGase 2 catalyzed the formation of water-insoluble dimers or polymers of alphaB-crystallin, betaB(2)-crystallin, and vimentin in HLE-B3 cells, providing evidence that TGase 2 may play a role in cataractogenesis. Thus, our findings indicate that in situ TGase 2 activity must be evaluated instead of in vitro activity to study the regulation mechanism and function of TGase 2 in biological and pathological processes.

Aging↗
PubMed2004

Validation of the Functional Assessment of Cancer Therapy-General (FACT-G) scale for measuring the health-related quality of life in Korean women with breast cancer.

BACKGROUND: The Functional Assessment of Cancer Therapy-General (FACT-G) scale, which was developed and validated in the USA, is widely used to measure the health-related quality of life in cancer patients. The purpose of the present study was to empirically validate the FACT-G scale with Korean breast cancer patients. METHODS: A convenience sample of 193 women with breast cancer was recruited from a university hospital. The subjects were asked to complete the Korean version of the FACT-G scale. The data were analyzed using exploratory factor analysis with varimax rotation to determine factor construct validity. The loading criterion was set at 0.40 and above, inter-subscale correlations were computed using Pearson correlation, and the reliability of the internal consistency for the total scale and its subscales were assessed by Cronbach's alpha. RESULTS: The factor structure of the Korean version of the FACT-G scale paralleled that of the English version: the physical, social/family, emotional, and functional well-being subscales were constructively valid in Korean breast cancer patients. However, there is the possibility of culture-specific differences in the social/family well-being subscale, and some problematic translations were revealed. Cronbach's alpha for the total scale was 0.89 and that for the subscales ranged from 0.78 to 0.90. CONCLUSION: The Korean version of the FACT-G scale was demonstrated as reliable and valid. Therefore, the scale can be used in research and clinical settings to assess the quality of life of Korean breast cancer patients.

Adult↗
PubMed2004

Three novel cis-acting elements required for efficient plus-strand DNA synthesis of the hepatitis B virus genome.

Synthesis of the relaxed-circular (RC) DNA genomes of hepadnaviruses by reverse transcriptase involves two template switches during plus-strand DNA synthesis. These template switches require repeat sequences (so-called donor and acceptor sites) between which a complementary strand of nucleic acid is transferred. To determine cis-acting elements apart from the donor and acceptor sites that are required for plus-strand RC DNA synthesis by hepatitis B virus (HBV), a series of mutants bearing a small deletion were made and analyzed for their impact on the viral genome synthesis. We found three novel cis-acting elements in the HBV genome: one element, located in the middle of the minus strand, is indispensable, whereas the other two elements, located near either end of the minus strand, contribute modestly to the plus-strand RC DNA synthesis. The data indicated that the first element facilitates plus-strand RNA primer translocation or subsequent elongation during plus-strand RC DNA synthesis, while the last two elements, although distantly located on the minus strand, act at multiple steps to promote plus-strand RC DNA synthesis. The necessity of multiple cis-acting elements on the minus-strand template reflects the complex nature of hepadnavirus reverse transcription.

Cell Line↗
PubMed2004

Association between major depressive disorder and the -1438A/G polymorphism of the serotonin 2A receptor gene.

This study investigated the possible effect of the -1438A/G single-nucleotide polymorphism in the promoter region of the serotonin 2A receptor (5-HTR2A) gene on major depressive disorder (MDD) in a Korean population. This polymorphism was analyzed in 189 patients with MDD and in 148 unrelated healthy controls using a case-control design, which revealed a significant difference in the genotype distributions (chi(2) = 10.78, d.f. = 2, p = 0.005). The frequency of the -1438G allele was also much higher in MDD patients than in normal controls (chi(2) = 7.20, p = 0.007; OR = 1.52, 95% CI 1.12-2.06). We also found significantly more carriers of the G allele (GG+AG genotypes) in MDD patients than in normal controls (chi(2) = 10.18, p = 0.001; OR = 2.46, 95% CI 1.40-4.32). Our results support the hypothesis that the -1438A/G polymorphism of the promoter region of the 5-HTR2A gene is associated with MDD patients in a Korean population.

Adult↗