• Title/Summary/Keyword: gene mutations

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Alteration of Substrate Specificity by Common Variants, E158K/E308G and V257M, in Human Hepatic Drug-metabolizing Enzyme, Flavin-containing Monooxygenase 3

  • Lee, Jung-Kyu;Kang, Ju-Hee;Cha, Young-Nam;Chung, Woon-Gye;Park, Chang-Shin
    • The Korean Journal of Physiology and Pharmacology
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    • v.7 no.3
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    • pp.157-162
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    • 2003
  • Our earlier studies found a significant correlation between the activities of ranitidine N-oxidation catalyzed by hepatic flavin-containing monooxygenase (FMO) and the presence of mutations in exon 4 (E158K) and exon 7 (E308G) of the FMO3 gene in Korean volunteers. However, caffeine N-1 demethylation (which is also partially catalyzed by FMO) was not significantly correlated with these FMO3 mutations. In this study, we examined another common mutation (V257M) in exon 6 of FMO3 gene. The V257M variant, which is caused by a point mutation (G769A), was commonly observed (13.21% allele frequency) in our subjects (n=159). This point mutation causes a substitution of $Val^{257}$ to $Met^{257}$, with transformation of the secondary structure. The presence of this mutant allele correlated significantly with a reduction in caffeine N-1-demethylating activity, but was not correlated with the activity of N-oxidation of ranitidine. In a family study, the low FMO activity observed in a person heterozygous for a nonsense mutation in exon 4 (G148X) and heterozygous for missense mutation in exon 6 (V257M) of FMO3 was attributed to the mutations. Our results suggest that various point mutations in the coding regions of FMO3 may influence FMO3 activity according to the probe substrates of varying chemical structure that correlate with each mutation on the FMO3 gene.

Germline Variations of Apurinic/Apyrimidinic Endonuclease 1 (APEX1) Detected in Female Breast Cancer Patients

  • Ali, Kashif;Mahjabeen, Ishrat;Sabir, Maimoona;Baig, Ruqia Mehmood;Zafeer, Maryam;Faheem, Muhammad;Kayani, Mahmood Akhtar
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.18
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    • pp.7589-7595
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    • 2014
  • Apurinic/apyrimidinic endonuclease 1 (APEX1) is a multifunctional protein which plays a central role in the BER pathway. APEX1 gene being highly polymorphic in cancer patients and has been indicated to have a contributive role in Apurinic/apyrimidinic (AP) site accumulation in DNA and consequently an increased risk of cancer development. In this case-control study, all exons of the APEX1 gene and its exon/intron boundaries were amplified in 530 breast cancer patients and 395 matched healthy controls and then analyzed by single-stranded conformational polymorphism followed by sequencing. Sequence analysis revealed fourteen heterozygous mutations, seven 5'UTR, one 3'UTR, two intronic and four missense. Among identified mutations one 5'UTR (rs41561214), one 3'UTR (rs17112002) and one missense mutation (Ser129Arg, Mahjabeen et al., 2013) had already been reported while the remaining eleven mutations. Six novel mutations (g.20923366T>G, g.20923435G>A, g.20923462G>A, g.20923516G>A, 20923539G>A, g.20923529C>T) were observed in 5'UTR region, two (g.20923585T>G, g.20923589T>G) in intron1 and three missense (Glu101Lys, Ala121Pro, Ser123Trp) in exon 4. Frequencues of 5'UTR mutations; g.20923366T>G, g.20923435G>A and 3'UTR (rs17112002) were calculated as 0.13, 0.1 and 0.1 respectively. Whereas, the frequency of missense mutations Glu101Lys, Ser123Trp and Ser129Arg was calculated as 0.05. A significant association was observed between APEX1 mutations and increased breast cancer by ~9 fold (OR=8.68, 95%CI=2.64 to 28.5) with g.20923435G>A (5'UTR), ~13 fold (OR= 12.6, 95%CI=3.01 to 53.0) with g.20923539G>A (5'UTR) and~5 fold increase with three missense mutations [Glu101Lys (OR=4.82, 95%CI=1.97 to 11.80), Ser123Trp (OR=4.62, 95%CI=1.7 to 12.19), Ser129Arg (OR=4.86, 95%CI=1.43 to 16.53)]. The incidence of observed mutations was found higher in patients with family history and with early menopause. In conclusion, our study demonstrates a significant association between germ line APEX1 mutations and breast cancer patients in the Pakistani population.

Diverse Mutations of rpoB in Rifampin-Resistant Mycobacteria (Rifampin에 대한 내성 마이코박테리아에서 rpoB의 다양한 변이)

  • Kweon, Tae-Dong;Sa, Young-Hee;Hong, Seong-Karp
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.10a
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    • pp.991-993
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    • 2012
  • We analyzed RNA polymerase beta subunit gene (rpoB) mutation of rifampin-resistant Mycobacteria through analysis of nucleotide sequence of rpoB DNA (351 bp) containing rifampin resistant region, $rif^r$. For this study, we collected rifampin-resistant Mycobacteria that were identified by conventional culture methods from Masan National Hospital and The Korean Institute of Tuberculosis. We performed sequencing of DNA nucleotides and analyzed rpoB gene of those rifampin-resistant Mycobacteria. From this analysis, we invcestigated diverse mutations of rpoB gene included rifampin-resistant gene, which were not reported, from those rifampin-resistant Mycobacteria.

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Improving siRNA design targeting nucleoprotein gene as antiviral against the Indonesian H5N1 virus

  • Hartawan, Risza;Pujianto, Dwi Ari;Dharmayanti, Ni Luh Putu Indi;Soebandrio, Amin
    • Journal of Veterinary Science
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    • v.23 no.2
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    • pp.24.1-24.10
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    • 2022
  • Background: Small interfering RNA technology has been considered a prospective alternative antiviral treatment using gene silencing against influenza viruses with high mutations rates. On the other hand, there are no reports on its effectiveness against the highly pathogenic avian influenza H5N1 virus isolated from Indonesia. Objectives: The main objective of this study was to improve the siRNA design based on the nucleoprotein gene (siRNA-NP) for the Indonesian H5N1 virus. Methods: The effectiveness of these siRNA-NPs (NP672, NP1433, and NP1469) was analyzed in vitro in Marbin-Darby canine kidney cells. Results: The siRNA-NP672 caused the largest decrease in viral production and gene expression at 24, 48, and 72 h post-infection compared to the other siRNA-NPs. Moreover, three serial passages of the H5N1 virus in the presence of siRNA-NP672 did not induce any mutations within the nucleoprotein gene. Conclusions: These findings suggest that siRNA-NP672 can provide better protection against the Indonesian strain of the H5N1 virus.

A Study on the Screening of the Novel Genes Associated with Lysosomal Trafficking and Mutation Detection in Fibroblasts of the Patients with Mucolipidosis type II and III (리소좀 교통 이상을 초래하는 뮤코지방증 2형과 3형 환자의 섬유아세포를 이용한 신규 유전자 탐색 및 돌연변이에 대한 연구)

  • Song, Seng Mi;Chang, Soo Hee;Paik, Kyung Hoon;Jin, Dong-Kyu
    • Journal of The Korean Society of Inherited Metabolic disease
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    • v.5 no.1
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    • pp.65-75
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    • 2005
  • Purpose: To understand genetic differences and similarities between mucolipidosis and control. Methods: Using the fibroblast of the mucolipidosis II and control, forward and reverse subtracted libraries were constructed. Among these clones, we investigated mutations in the GNPTA (MGC4170) gene, which codes for the ${\alpha}/{\beta}$ subunits of phosphotransferase, and in the GNPTAG gene, which codes for the ${\gamma}$ subunits in 5 Korean patients with mucolipidosis type II or IIIA. Result: Several differentially expressed cDNAs were cloned and their sequences were determined. Mutation analysis of the interested gene, GNPTA was performed and we identified 7 mutations in the GNPTA gene, but none in the GNPTAG gene. The mutations in type II patients included p.Q104X(c.310C>T), p.R1189X(c.3565C>T), p.S1058X(c.3173C>G), p.W894X(c.2681G>A) and p.H1158fsX15(c.3474_3475delTA), all of which are non-sense or frame shift mutations. However, a splicing site mutation, IVS13+1G>A (c.2715+1G>A) was detected along with a non-sense or a frame shift mutation (p.R1189X or p.E858fsX3(c.2574_2575delGA)) in two mucolipidosis type IIIA patients. Conclusion: This report shows that mutations in the GNPTA gene coding for the ${\alpha}{\beta}$subunits of phosphotransferase, and not mutations in the GNPTAG gene, account for most of mutations found in Korean patients with mucolipidosis type II or IIIA.

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Functional Characterization of ABCB4 Mutations Found in Low Phospholipid-Associated Cholelithiasis (LPAC)

  • Kim, Tae Hee;Park, Hyo Jin;Choi, Ji Ha
    • The Korean Journal of Physiology and Pharmacology
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    • v.17 no.6
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    • pp.525-530
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    • 2013
  • Multidrug resistance 3 (MDR3) is expressed on the canalicular membrane of the hepatocytes and plays an important role in protecting the liver from bile acids. Altered ABCB4 gene expression can lead to a rare hepatic disease, low phospholipid-associated cholelithiasis (LPAC). In this study, we characterized 3 ABCB4 mutations in LPAC patients using various in vitro assay systems. We first measured the ability of each mutant to transport paclitaxel and then the mechanisms by which these mutations might change MDR3 transport activity were determined using immunoblotting, cell surface protein biotinylation, and immunofluorescence. Through a membrane vesicular transport assay, we observed that the uptake of paclitaxel was significantly reduced in membrane vesicles expressing 2 ABCB4 mutations, F165I and S320F. Both mutants showed significantly decreased total and cell surface MDR3 expression. These data suggest two missense mutations of ABCB4 may alter function of MDR3 and ultimately can be determined as LPAC-causing mutations.