Sample records for reductase mthfr mutation

  1. Mortality risk in men is associated with a common mutation in the methylenetetrahydrofolate reductase gene (MTHFR)

    Microsoft Academic Search

    Bastiaan T Heijmans; Jacobijn Gussekloo; Cornelis Kluft; Simone Droog; A Margot Lagaay; Dick L Knook; Rudi GJ Westendorp; Eline P Slagboom

    1999-01-01

    An elevated level of homocysteine in plasma is associated with the occurrence of cardiovascular disease. A common ala-to-val mutation in the methylenetetrahydrofolate reductase gene (MTHFR) is associated with an elevated level of plasma homocysteine. We studied the possible detrimental effects of the MTHFR mutation on mortality. Within a population-based study in the city of Leiden, the Netherlands, we first compared

  2. Gene structure of human and mouse methylenetetrahydrofolate reductase (MTHFR)

    Microsoft Academic Search

    Philippe Goyette; Aditya Pai; Renate Milos; Phyllis Frosst; Pamela Tran; Zhoutao Chen; Manuel Chan; Rima Rozen

    1998-01-01

    .   Methylenetetrahydrofolate reductase (MTHFR) catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate,\\u000a a co-substrate for homocysteine remethylation to methionine. A human cDNA for MTHFR, 2.2 kb in length, has been expressed\\u000a and shown to result in a catalytically active enzyme of approximately 70 kDa. Fifteen mutations have been identified in the\\u000a MTHFR gene: 14 rare mutations associated with severe enzymatic deficiency

  3. Pregnancy-associated osteoporosis with a heterozygous deactivating LDL receptor-related protein 5 (LRP5) mutation and a homozygous methylenetetrahydrofolate reductase (MTHFR) polymorphism.

    PubMed

    Cook, Fiona J; Mumm, Steven; Whyte, Michael P; Wenkert, Deborah

    2014-04-01

    Pregnancy-associated osteoporosis (PAO) is a rare, idiopathic disorder that usually presents with vertebral compression fractures (VCFs) within 6 months of a first pregnancy and delivery. Spontaneous improvement is typical. There is no known genetic basis for PAO. A 26-year-old primagravida with a neonatal history of unilateral blindness attributable to hyperplastic primary vitreous sustained postpartum VCFs consistent with PAO. Her low bone mineral density (BMD) seemed to respond to vitamin D and calcium therapy, with no fractures after her next successful pregnancy. Investigation of subsequent fetal losses revealed homozygosity for the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism associated both with fetal loss and with osteoporosis (OP). Because her neonatal unilateral blindness and OP were suggestive of loss-of-function mutation(s) in the gene that encodes LDL receptor-related protein 5 (LRP5), LRP5 exon and splice site sequencing was also performed. This revealed a unique heterozygous 12-bp deletion in exon 21 (c.4454_4465del, p.1485_1488del SSSS) in the patient, her mother and sons, but not her father or brother. Her mother had a normal BMD, no history of fractures, PAO, ophthalmopathy, or fetal loss. Her two sons had no ophthalmopathy and no skeletal issues. Her osteoporotic father (with a family history of blindness) and brother had low BMDs first documented at ages ?40 and 32 years, respectively. Serum biochemical and bone turnover studies were unremarkable in all subjects. We postulate that our patient's heterozygous LRP5 mutation together with her homozygous MTHFR polymorphism likely predisposed her to low peak BMD. However, OP did not cosegregate in her family with the LRP5 mutation, the homozygous MTHFR polymorphism, or even the combination of the two, implicating additional genetic or nongenetic factors in her PAO. Nevertheless, exploration for potential genetic contributions to PAO may explain part of the pathogenesis of this enigmatic disorder and identify some at-risk women. PMID:24014470

  4. Common Mutations of the Methylenetetrahydrofolate Reductase (MTHFR) Gene in Non-Syndromic Cleft Lips and Palates Children in North-West of Iran

    PubMed Central

    Abdollahi-Fakhim, Shahin; Asghari Estiar, Mehrdad; Varghaei, Parizad; Alizadeh Sharafi, Mahdi; Sakhinia, Masoud; Sakhinia, Ebrahim

    2015-01-01

    Introduction: Cleft lips and cleft palates are common congenital abnormalities in children. Various chromosomal loci have been suggested to be responsible the development of these abnormalities. The present study was carried out to investigate the association between the suspected genes (methylenetetrahydrofolate reductase [MTHFR] A1298C and C677T) that might contribute into the etiology of these disorders through application of molecular methods. Materials and Methods: This cross-sectional and explanatory study was carried out on a study population of 65 affected children, 130 respective parents and 50 healthy individuals between 2009 and 2012 at Tabriz University of Medical Sciences, IR Iran. After DNA extraction, amplification refractory mutation system–polymerase chain reaction (ARMS-PCR) and restriction fragment length polymorphism (RFLP)-PCR were used respectively to investigate the C677T and A1298C mutations for the MTHFR gene. Results: There was a significant difference in the rates of the C677T mutation when affected patients and their fathers were compared with the control group (odds ratio [OR]=0.44) (OR=0.64). However, there was no significant difference observed in the rate of this mutation between the patients’ mothers and the control group (OR=1.35). In addition, the abnormality rate was higher in patients with the A1298C mutation and their parents, when compared with the control group. This abnormality rate was higher for the affected children and their fathers in comparison with their mothers (Fathers, OR=0.26; Mothers, OR=0.65; Children, OR=0.55). No significant difference was seen in the rate of the polymorphism C677T in its CC, when the affected children and their parents were compared with the control group. However, there was a significant difference in the A1298C mutation. Conclusion: An association was seen between the A1298C mutation and cleft lip and cleft palate abnormalities in Iran. However, there seems to be a stronger relationship between the C67TT mutation and these abnormalities in other countries, which could be explained by racial differences. Moreover, this association was more notable between the affected children and their fathers than their mothers. The findings in this study may be helpful in future studies and screening programs. PMID:25745606

  5. A Second Genetic Polymorphism in Methylenetetrahydrofolate Reductase (MTHFR) Associated with Decreased Enzyme Activity

    Microsoft Academic Search

    Ilan Weisberg; Pamela Tran; Benedicte Christensen; Sahar Sibani; Rima Rozen

    1998-01-01

    A common mutation in methylenetetrahydrofolate reductase (MTHFR), C677T, results in a thermolabile variant with reduced activity. Homozygous mutant individuals (approximately 10% of North Americans) are predisposed to mild hyperhomocysteinemia, when their folate status is low. This genetic–nutrient interactive effect is believed to increase the risk for neural tube defects and vascular disease. In this communication, we characterize a second common

  6. The thermolabile variant of methylenetetrahydrofolate reductase (MTHFR) is not a major risk factor for neural tube defect in American Caucasians

    Microsoft Academic Search

    Marcy C. Speer; Gordon Worley; Joanne F. Mackey; Elizabeth Melvin; W. Jerry Oakes; Timothy M. George

    1997-01-01

    Mutations in the gene for methylenetetrahydrofolate reductase (MTHFR) have been implicated as a risk factor in the formation\\u000a of neural tube defects. We investigated this gene in a series of 65 sporadic American Caucasians patients with lumbosacral\\u000a NTD and their unaffected parents, using both case-control design and assessment of linkage disequilibrium. We found no evidence\\u000a to support mutations in MTHFR

  7. Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism: epidemiology, metabolism and the associated diseases.

    PubMed

    Liew, Siaw-Cheok; Gupta, Esha Das

    2015-01-01

    The Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is associated with various diseases (vascular, cancers, neurology, diabetes, psoriasis, etc) with the epidemiology of the polymorphism of the C677T that varies dependent on the geography and ethnicity. The 5,10-Methylenetetrahydrofolate reductase (MTHFR) locus is mapped on chromosome 1 at the end of the short arm (1p36.6). This enzyme is important for the folate metabolism which is an integral process for cell metabolism in the DNA, RNA and protein methylation. The mutation of the MTHFR gene which causes the C677T polymorphism is located at exon 4 which results in the conversion of valine to alanine at codon 222, a common polymorphism that reduces the activity of this enzyme. The homozygous mutated subjects have higher homocysteine levels while the heterozygous mutated subjects have mildly raised homocysteine levels compared with the normal, non-mutated controls. Hyperhomocysteinemia is an emerging risk factor for various cardiovascular diseases and with the increasing significance of this polymorphism in view of the morbidity and mortality impact on the patients, further prevention strategies and nutritional recommendations with the supplementation of vitamin B12 and folic acid which reduces plasma homocysteine level would be necessary as part of future health education. This literature review therefore focuses on the recent evidence-based reports on the associations of the MTHFR C677T polymorphism and the various diseases globally. PMID:25449138

  8. Homozygous C677T mutation in the MTHFR gene as an independent risk factor for multiple small-artery occlusions

    Microsoft Academic Search

    B. O Choi; N. K Kim; S. H Kim; M. S Kang; S Lee; J. Y Ahn; O. J Kim; D Oh

    2003-01-01

    Introduction: Hyperhomocysteinemia is an independent risk factor for cerebrovascular disease and the homozygous C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene can induce hyperhomocysteinemia. However, the association between this 677TT genotype and ischemic stroke still remains controversial. Therefore, we carried out this study to determine whether the MTHFR TT genotype is associated with certain subtypes of ischemic stroke. Materials and

  9. The 1298A?C polymorphism in methylenetetrahydrofolate reductase (MTHFR): in vitro expression and association with homocysteine

    Microsoft Academic Search

    Ilan S. Weisberg; Paul F. Jacques; Jacob Selhub; Andrew G. Bostom; Zhoutao Chen; R. Curtis Ellison; John H. Eckfeldt; Rima Rozen

    2001-01-01

    A common mutation in methylenetetrahydrofolate reductase (MTHFR), 677C?T, is associated with reduced enzyme activity, a thermolabile enzyme and mild hyperhomocysteinemia, a risk factor for vascular disease. Recently, a second common mutation (1298A?C; glutamate to alanine) was reported, but this mutation was suggested to increase homocysteine only in individuals who carried the bp677 variant. To evaluate the functional consequences of this

  10. Methylenetetrahydrofolate reductase mutations, a genetic cause for familial recurrent neural tube defects.

    PubMed

    Yaliwal, Laxmi V; Desai, Rathnamala M

    2012-01-01

    Methylenetetrahydrofolate reductase (MTHFR) gene mutations have been implicated as risk factors for neural tube defects (NTDs). The best-characterized MTHFR genetic mutation 677C?T is associated with a 2-4 fold increased risk of NTD if patient is homozygous for this mutation. This risk factor is modulated by folate levels in the body. A second mutation in the MTHFR gene is an A?C transition at position 1298. The 1298A?C mutation is also a risk factor for NTD, but with a smaller relative risk than 677C?T mutation. Under conditions of low folate intake or high folate requirements, such as pregnancy, this mutation could become of clinical importance. We present a case report with MTHFR genetic mutation, who presented with recurrent familial pregnancy losses due to anencephaly/NTDs. PMID:22754237

  11. Hyperhomocyst(e)inaemia, but not MTHFR C677T mutation, as a risk factor for non-arteritic ischaemic optic neuropathy

    Microsoft Academic Search

    Martin Weger; Olaf Stanger; Hannes Deutschmann; Michael Simon; Wilfried Renner; Otto Schmut; Jürgen Semmelrock; Anton Haas

    2001-01-01

    BACKGROUND\\/AIMSHyperhomocyst(e)inaemia has been identified as a strong risk factor for stroke, myocardial infarction, and deep vein thrombosis. A point mutation of methylene tetrahydrofolate reductase (MTHFR C677T) has been associated with increased plasma homocyst(e)ine levels. To investigate whether hyperhomocyst(e)inaemia and\\/or MTHFR C677T mutation are associated with non-arteritic ischaemic optic neuropathy (NAION), a case-control study including 59 consecutive patients with NAION and

  12. Mutation (677 C to T) in the methylenetetrahydrofolate reductase gene aggravates hyperhomocysteinemia in hemodialysis patients

    Microsoft Academic Search

    Manuela Födinger; Christine Mannhalter; Gabriele Wölfl; Ingrid Pabinger; Eva Müller; Rainer Schmid; Walter H Hörl; Gere Sunder-Plassmann

    1997-01-01

    Mutation 677 C to T in the methylenetetrahydrofolate reductase gene aggravates hyperhomocysteinemia in hemodialysis patients. Hyperhomocysteinemia is frequent in hemodialysis patients and represents an independent risk factor for vascular disease in these patients. Elevated total homocysteine (tHcy) plasma levels can result from defective remethyla-tion of Hcy to methionine due to decreased activity of the enzyme methylenetetrahydrofolate reductase (MTHFR). A genetic

  13. Folate and breast cancer: the role of polymorphisms in methylenetetrahydrofolate reductase (MTHFR)

    Microsoft Academic Search

    L Sharp; J Little; A. C Schofield; E Pavlidou; S. C Cotton; Z Miedzybrodzka; J. O. C Baird; N. E Haites; S. D Heys; D. A Grubb

    2002-01-01

    Evidence is growing that low folate status may be a factor in the aetiology of several cancers, including breast cancer. The methylenetetrahydrofolate reductase gene (MTHFR), which has a key role in folate metabolism, is polymorphic. We report a case-control study of two functional polymorphisms in MTHFR, dietary folate intake and breast cancer. Sixty-two cases with invasive breast cancer and sixty-six

  14. Polymorphisms of methylenetetrahydrofolate reductase ( MTHFR), methionine synthase ( MTR), methionine synthase reductase ( MTRR), and thymidylate synthase ( TYMS) in multiple myeloma risk

    Microsoft Academic Search

    Carmen S. P. Lima; Manoela M. Ortega; Margareth C. Ozelo; Renato C. Araujo; Cármino A. De Souza; Irene Lorand-Metze; Joyce M. Annichino-Bizzacchi; Fernando F. Costa

    2008-01-01

    We tested whether the polymorphisms of the methylenetetrahydrofolate reductase gene, MTHFR C677T and A1298C, the methionine synthase gene, MTR A2756G, the methionine synthase reductase gene, MTRR A66G, and the thymidylate synthase gene, TYMS 2R?3R, involved in folate and methionine metabolism, altered the risk for multiple myeloma (MM). Genomic DNA from 123MM patients and 188 controls was analysed by polymerase chain

  15. Genetic variants in 3'-UTRs of methylenetetrahydrofolate reductase (MTHFR) predict colorectal cancer susceptibility in Koreans.

    PubMed

    Joo Jeon, Young; Woo Kim, Jong; Mi Park, Hye; Kim, Jung O; Geun Jang, Hyo; Oh, Jisu; Gyu Hwang, Seong; Won Kwon, Sung; Oh, Doyeun; Keun Kim, Nam

    2015-01-01

    Polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) play important roles in tumor development, progression, and metastasis. Moreover, recent studies have reported that a number of 3'-UTR polymorphisms potentially bind to specific microRNAs in a variety of cancers. The aim of this study was to investigate the association of four MTHFR polymorphisms, 2572C>A [rs4846049], 4869C>G [rs1537514], 5488C>T [rs3737967], and 6685T>C [rs4846048] with colorectal cancer (CRC) in Koreans. A total of 850 participants (450 CRC patients and 400 controls) were enrolled in the study. The genotyping of MTHFR 3'-UTR polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism analysis or TaqMan allelic discrimination assay. We found that MTHFR 2572C>A, 4869C>G, and 5488C>T genotypes were substantially associated with CRC susceptibility. Of the potentially susceptible polymorphisms, MTHFR 2572C>A was associated with increased homocysteine and decreased folate levels in the plasma based on MTHFR 677CC. Our study provides the evidences for 3'-UTR variants in MTHFR gene as potential biomarkers for use in CRC prevention. PMID:26046315

  16. Genetic variants in 3?-UTRs of methylenetetrahydrofolate reductase (MTHFR) predict colorectal cancer susceptibility in Koreans

    PubMed Central

    Joo Jeon, Young; Woo Kim, Jong; Mi Park, Hye; Kim, Jung O; Geun Jang, Hyo; Oh, Jisu; Gyu Hwang, Seong; Won Kwon, Sung; Oh, Doyeun; Keun Kim, Nam

    2015-01-01

    Polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) play important roles in tumor development, progression, and metastasis. Moreover, recent studies have reported that a number of 3?-UTR polymorphisms potentially bind to specific microRNAs in a variety of cancers. The aim of this study was to investigate the association of four MTHFR polymorphisms, 2572C>A [rs4846049], 4869C>G [rs1537514], 5488C>T [rs3737967], and 6685T>C [rs4846048] with colorectal cancer (CRC) in Koreans. A total of 850 participants (450 CRC patients and 400 controls) were enrolled in the study. The genotyping of MTHFR 3?-UTR polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism analysis or TaqMan allelic discrimination assay. We found that MTHFR 2572C>A, 4869C>G, and 5488C>T genotypes were substantially associated with CRC susceptibility. Of the potentially susceptible polymorphisms, MTHFR 2572C>A was associated with increased homocysteine and decreased folate levels in the plasma based on MTHFR 677CC. Our study provides the evidences for 3?-UTR variants in MTHFR gene as potential biomarkers for use in CRC prevention. PMID:26046315

  17. C677T MTHFR mutation and factor V Leiden mutation in patients with TIA/minor stroke: a case-control study.

    PubMed

    Lalouschek, W; Aull, S; Serles, W; Schnider, P; Mannhalter, C; Pabinger-Fasching, I; Deecke, L; Zeiler, K

    1999-01-15

    A common C677T mutation in the gene for the enzyme 5,10-methylenetetrahydrofolate reductase (5,10-MTHFR) has been linked to elevated levels of homocysteine and was therefore suspected to be a candidate genetic risk factor for arterial occlusive disease. Another mutation, factor V Leiden, has been established as a common hereditary risk factor for venous thrombosis, but its role in arterial disease remains controversial. We investigated the prevalence of both the C677T MTHFR mutation and the factor V Leiden mutation in 81 patients with transient ischemic attack (TIA) or minor stroke (MS) and in 81 age- and sex-matched control subjects free from clinically manifest vascular disease. We further compared clinical and laboratory data as well as clinical course of patients carrying the factor V Leiden mutation alone or in combination with the C677T MTHFR mutation and mutation-free patients. The prevalence of the MTHFR mutation did not differ between patients and control subjects with 11.1% homozygous carriers in both groups (OR for homozygous carriers 1.0; 95% CI 0.38-2.66). However, there was a trend towards a higher prevalence of carriers of factor V Leiden in patients (12.3%) than in control subjects (4.9%) (OR 2.75; 95% CI 0.83-9.17;p=0.09). Furthermore, we found some evidence that the combined occurrence of the C677T MTHFR mutation and factor V Leiden might unfavorably affect the clinical course of the disease, but the number of respective patients was small. Larger studies with a greater number of carriers of both the C677T MTHFR mutation and factor V Leiden seem therefore warranted. PMID:9950259

  18. Association between 5, 10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms and congenital heart disease: A meta-analysis?

    PubMed Central

    Wang, Wenju; Hou, Zongliu; Wang, Chunhui; Wei, Chuanyu; Li, Yaxiong; Jiang, Lihong

    2013-01-01

    Background Inconsistent results were reported in recent literature regarding the association between methylenetetrahydrofolate reductase (MTHFR) C677T/A1298C polymorphisms and the susceptibility of congenital heart disease (CHD). In this study, we performed a meta-analysis to investigate the associations by employing multiple analytical methods. Methods Literature search was performed and published articles were obtained from PubMed, Embase and CNKI databases based on the exclusion and inclusion criteria. Data were extracted from eligible studies and the crude odds ratios and their corresponding 95% confidence intervals (CIs) were calculated using random or fix effects model to evaluate the associations between the MTHFR C677T/A1298C polymorphisms and CHD development. Subgroup based analysis was performed by Hardy–Weinberg equilibrium, ethnicity, types of CHD, source of control and sample size. Results Twenty-four eligible studies were included in this meta-analysis. Significant association was found between fetal MTHFR C677T polymorphism and CHD development in all genetic models. The pooled ORs and 95% CIs in all genetic models indicated that MTHFR C677T polymorphism was significantly associated with CHD in Asian, but not Caucasian in subgroup analysis. The maternal MTHFR C677T polymorphism was not associated with CHD except for recessive model. Moreover, neither maternal nor fetal MTHFR A1298C polymorphism was associated with CHD. Conclusion The fetal MTHFR C677T polymorphism may increase the susceptibility to CHD. Fetal MTHFR C677T polymorphism was more likely to affect Asian fetus than Caucasian. The MTHFR A1298C polymorphism may not be a risk of congenital heart disease. PMID:25606381

  19. A second common variant in the methylenetetrahydrofolate reductase (MTHFR) gene and its relationship to MTHFR enzyme activity, homocysteine, and cardiovascular disease risk

    Microsoft Academic Search

    Karin J. Lievers; Godfried H. Boers; Petra Verhoef; Martin Heijer; Leo A. Kluijtmans; Nathalie M. Put; Frans J. Trijbels; Henk J. Blom

    2001-01-01

    Molecular defects in genes encoding enzymes involved in homocysteine metabolism may account for mild hyperhomocysteinemia, an independent and graded risk factor for cardiovascular disease (CVD). We examined the relationship of two polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, the 677CMT and 1298AMC variants, to MTHFR activity, homocysteine concentrations, and risk of CVD in a population of 190 vascular disease patients

  20. Plasma folate, methylenetetrahydrofolate reductase (MTHFR), and colorectal cancer risk in three large nested case-control studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Few prospective studies have examined the associations between blood levels of folate, in conjunction with methylenetetrahydrofolate reductase (MTHFR) polymorphisms, and colorectal cancer. We evaluated the associations between plasma folate, MTHFR C677T, and A1298C, and colorectal cancer in three la...

  1. 5,10-Methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTRR), and methionine synthase reductase (MTR) gene polymorphisms and adult meningioma risk.

    PubMed

    Zhang, Jun; Zhou, Yan-Wen; Shi, Hua-Ping; Wang, Yan-Zhong; Li, Gui-Ling; Yu, Hai-Tao; Xie, Xin-You

    2013-11-01

    The causes of meningiomas are not well understood. Folate metabolism gene polymorphisms have been shown to be associated with various human cancers. It is still controversial and ambiguous between the functional polymorphisms of folate metabolism genes 5,10-methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTRR), and methionine synthase reductase (MTR) and risk of adult meningioma. A population-based case–control study involving 600 meningioma patients (World Health Organization [WHO] Grade I, 391 cases; WHO Grade II, 167 cases; WHO Grade III, 42 cases) and 600 controls was done for the MTHFR C677T and A1298C, MTRR A66G, and MTR A2756G variants in Chinese Han population. The folate metabolism gene polymorphisms were determined by using a polymerase chain reaction–restriction fragment length polymorphism assay. Meningioma cases had a significantly lower frequency of MTHFR 677 TT genotype [odds ratio (OR) = 0.49, 95 % confidence interval (CI) 0.33–0.74; P = 0.001] and T allele (OR = 0.80, 95 % CI 0.67–0.95; P = 0.01) than controls. A significant association between risk of meningioma and MTRR 66 GG (OR = 1.41, 95 % CI 1.02–1.96; P = 0.04) was also observed. When stratifying by the WHO grade of meningioma, no association was found. Our study suggested that MTHFR C677T and MTRR A66G variants may affect the risk of adult meningioma in Chinese Han population. PMID:23959833

  2. Is methylenetetrahydrofolate reductase (MTHFR) gene A1298C polymorphism related with varicocele risk?

    PubMed

    Ucar, V B; Nami, B; Acar, H; Kilinç, M

    2015-02-01

    Varicocele is one of the main reasons for male infertility the exact aetiology of which remains unclear. Methylenetetrahydrofolate reductase (MTHFR) is important for DNA synthesis and methylation, which has a key role during spermatogenesis. Numerous literature suggests that the MTHFR polymorphism may be genetic risk factors for male infertility. In this study, we evaluated C677T and A1298C MTHFR gene polymorphism frequency in patients with varicocele and normal men. A total of 107 varicocele patients and 109 fertile healthy individuals were included. Genotyping of the MTHFR gene in C677T and A1298C base pairs carried out by using real-time PCR technique and afterwards, the statistical analysis accomplished. There is a statistical difference for the frequency of 1298AA genotype in patients with varicocele compared with normal controls (P = 0.0051, OR = 2.2750). Instead, subsequently, 1298/A allel frequency in patient group was significantly higher in comparison with control group (P = 0.0174). According to our results, 1298AA genotype in MTHFR gene raises the risk of varicocele approximately 2.3 times more compared with men carrying other genotypes. The results show that genetic factors have an important role in the molecular basis of varicocele. PMID:24456105

  3. Seven novel mutations in the methylenetetrahydrofolate reductase gene and genotype/phenotype correlations in severe methylenetetrahydrofolate reductase deficiency

    SciTech Connect

    Goyette, P.; Frosst, P.; Rosenblatt, D.S.; Rozen. R. [McGill Univ., Montreal (Canada)

    1995-05-01

    5-Methyltetrahydrofolate, the major form of folate in plasma, is a carbon donor for the remethylation of homocysteine to methionine. This form of folate is generated from 5,10-methylenetetrahydrofolate through the action of 5,10-methylenetetrahydrofolate reductase (MTHFR), a cytosolic flavoprotein. Patients with an autosomal recessive severe deficiency of MTHFR have homocystinuria and a wide range of neurological and vascular disturbances. We have recently described the isolation of a cDNA for MTHFR and the identification of two mutations in patients with severe MTHFR deficiency. We report here the characterization of seven novel mutations in this gene: six missense mutations and a 5{prime} splice-site defect that activates a cryptic splice in the coding sequence. We also present a preliminary analysis of the relationship between genotype and phenotype for all nine mutations identified thus far in this gene. A nonsense mutation and two missense mutations (proline to leucine and threonine to methionine) in the homozygous state are associated with extremely low activity (0%-3%) and onset of symptoms within the 1st year of age. Other missense mutations (arginine to cysteine and arginine to glutamine) are associated with higher enzyme activity and later onset of symptoms. 19 refs., 4 figs., 2 tabs.

  4. Association of Methylenetetrahydrofolate Reductase (MTHFR) Polymorphism with Bone Mineral Density in Postmenopausal Japanese Women

    Microsoft Academic Search

    M. Miyao; H. Morita; T. Hosoi; H. Kurihara; S. Inoue; S. Hoshino; M. Shiraki; Y. Yazaki; Y. Ouchi

    2000-01-01

    .   The pathogenesis of osteoporosis is controlled by genetic and environmental factors. Considering the high prevalence of osteoporosis\\u000a in homocystinuria, abnormal homocysteine metabolism would contribute to the pathogenesis of osteoporosis. It is known that\\u000a the polymorphism of methylenetetrahydrofolate reductase (MTHFR), the enzyme catalyzing the reduction of 5,10-methylenetetrahydrofolate\\u000a to 5-methyltetrahydrofolate, correlates with hyperhomocysteinemia. In this study, we examined the association of

  5. Retrospective approach to methylenetetrahydrofolate reductase mutations in children.

    PubMed

    Özer, I??l; Özçetin, Mustafa; Karaer, Hatice; Kurt, Semiha G; ?ahin, ?emsettin

    2011-07-01

    Methylenetetrahydrofolate reductase reduces methyltetrahydrofolate, a cosubstrate in the remethylation of homocysteine, from methylenetetrahydrofolate. Congenital defects, hematologic tumors, and intrauterine growth retardation can occur during childhood. This study evaluated clinical and laboratory treatment approaches in children diagnosed with methylenetetrahydrofolate reductase mutations. Our group included 23 boys and 14 girls, aged 103.4 ± 70.8 months S.D. Clinical findings of patients and homocysteine, vitamin B12, folate, hemogram, electroencephalography, cranial magnetic resonance imaging, and echocardiography data were evaluated in terms of treatment approach. Our patients' findings included vitamin B12 at 400.4 ± 224.6 pg/mL S.D. (normal range, 300-700 pg/mL), folate at 10.1 ± 4.5 ng/mL S.D. (normal range, 1.8-9 ng/mL), and homocysteine at 8.4 ± 4.7 ?mol/L S.D. (normal range, 5.5-17 ?mol/L). Eighty-eight percent of patients demonstrated clinical findings. In comparisons involving categorical variables between groups, ?(2) tests were used. No relationship was evident between mutation type, laboratory data, and clinical severity. All mothers who had MTHFR mutations and had babies with sacral dimples had taken folate supplements during pregnancy. To avoid the risk of neural tube defects, pregnant women with a MTHFR mutation may require higher than normally recommended doses of folic acid supplementation for optimum health. PMID:21723457

  6. Factor V gene G1691A mutation, prothrombin gene G20210A mutation, and MTHFR gene C677T mutation are not risk factors for pulmonary thromboembolism in Chinese population

    Microsoft Academic Search

    Yanhui Lu; Yanfen Zhao; Guozhang Liu; Xiaoling Wang; Zhihong Liu; Baiping Chen; Rutai Hui

    2002-01-01

    A mutation in coagulant factor V gene, a substitution in the 3? untranslated region of prothrombin gene, and a variant in 5,10-methylenetetrahydrofolate reductase (MTHFR) gene have been reported to be related to venous thromboembolism in Caucasians, but this relationship remains in debate in other populations. In this case–control study, we aimed to determine the prevalence of these three mutations in

  7. Unilateral Renal Vein Thrombosis and Adrenal Hemorrhage in A Newborn with Homozygous Factor V Leiden and Heterozygous Of MTHFR-677T, MTHFR-1298C Gene Mutations.

    PubMed

    Sandal, Gonca; Ar?kan, Elvan; Kuybulu, Ayça Esra; Ormec?, Ahmet Rifat

    2014-09-01

    Renal vein thrombosis (RVT) occurs as an acute and life-threatening event in neonates. RVT is the most common non-catheter-related thrombosis in infancy and occurs primarily in the newborn period. Non-catheter-related abdominal thrombosis on neonates has a higher incidence of genetic prothrombotic risk factors. RVT and adrenal hemorrhage can both be encountered in the neonatal period and they may occur at the same time (Bokenkamp et al., Eur J Pediatr 159:44-8, 2000; Lau et al. Pediatrics 120:1278-84, 2007). We report a case of unilateral RVT and adrenal hemorrhage in a newborn with homozygous factor V Leiden mutation and heterozygous of the methylene tetrahydrofolate reductase (MTHFR) gene mutations. PMID:25332602

  8. Riboflavin status modifies the effects of methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) polymorphisms on homocysteine.

    PubMed

    García-Minguillán, Carlos J; Fernandez-Ballart, Joan D; Ceruelo, Santiago; Ríos, Lídia; Bueno, Olalla; Berrocal-Zaragoza, Maria Isabel; Molloy, Anne M; Ueland, Per M; Meyer, Klaus; Murphy, Michelle M

    2014-11-01

    Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR), riboflavin-dependent enzymes, participate in homocysteine metabolism. Reported effects of riboflavin status on the association between the MTHFR 677C>T polymorphism and homocysteine vary, and the effects of the MTRR 66A>G or MTRR 524C>T polymorphisms on homocysteine are unclear. We tested the hypothesis that the effects of the MTHFR 677C>T, MTRR 66A>G and MTRR 524C>T polymorphisms on fasting plasma total homocysteine (tHcy) depend on riboflavin status (erythrocyte glutathionine reductase activation coefficient, optimum: <1.2; marginally deficient: 1.2-1.4; deficient: ?1.4) in 771 adults aged 18-75 years. MTHFR 677T allele carriers with middle or low tertile plasma folate (<14.7 nmol/L) had 8.2 % higher tHcy compared to the 677CC genotype (p < 0.01). This effect was eliminated when riboflavin status was optimal (p for interaction: 0.048). In the lowest cobalamin quartile (?273 pmol/L), riboflavin status modifies the relationship between the MTRR 66 A>G polymorphism and tHcy (p for interaction: 0.034). tHcy was 6.6 % higher in MTRR 66G allele carriers compared to the 66AA genotype with marginally deficient or optimal riboflavin status, but there was no difference when riboflavin status was deficient (p for interaction: 0.059). tHcy was 13.7 % higher in MTRR 524T allele carriers compared to the 524CC genotype when cobalamin status was low (p < 0.01), but no difference was observed when we stratified by riboflavin status. The effect of the MTHFR 677C>T polymorphism on tHcy depends on riboflavin status, that of the MTRR 66A>G polymorphism on cobalamin and riboflavin status and that of the MTRR 524C>T polymorphism on cobalamin status. PMID:25322900

  9. A Second Common Mutation in the Methylenetetrahydrofolate Reductase Gene: An Additional Risk Factor for Neural-Tube Defects?

    Microsoft Academic Search

    Fons Gabreëls; Erik M. B. Stevens; Jan A. M. Smeitink; Frans J. M. Trijbels; Tom K. A. B. Eskes; Lambert P. van den Heuvel; Henk J. Blom

    1998-01-01

    Summary Recently, we showed that homozygosity for the common 677(CrT) mutation in the methylenetetrahydrofolate reductase (MTHFR) gene, causing thermolability of the enzyme, is a risk factor for neural-tube defects (NTDs). We now report on another mutation in the same gene, the 1298(ArC) mutation, which changes a glutamate into an alanine residue. This mutation destroys anMboII recognition site and has an

  10. Evidence of Paternal N5, N10 - Methylenetetrahydrofolate Reductase (MTHFR) C677T Gene Polymorphism in Couples with Recurrent Spontaneous Abortions (RSAs) in Kolar District- A South West of India

    PubMed Central

    Vanilla, Shiny; Kotur, Pushpa F; Kutty, Moideen A; Vegi, Pradeep Kumar

    2015-01-01

    Introduction: Recurrent spontaneous abortion (RSA) is a multifactorial clinical obstetrics complication commonly occurring in pregnancy. Many research studies have noted the mutations such as C677T in N5, N10 - Methylenetetrahydrofolate reductase (MTHFR)gene which is regarded as RSA risk factor. This study was carried out to determine the occurrence of frequency of C677T of the MTHFR gene mutations with RSA. Aim: The purpose of present study is to determine the frequency of MTHFR C677T polymorphisms in couples with recurrent pregnancy loss and the impact of paternal polymorphisms of MTHFR C677T in recurrent pregnancy loss in population of couples living in Kolar district of Karnataka with RSA. Design: A total of 15 couples with a history of two or more unexplained RSA were enrolled as subjects in the study and a total of 15 couples with normal reproductive history, having two or more children and no history of miscarriages were enrolled as controls. Materials and Methods: DNA extraction from samples case and control group couples and its quantification by Agarose gel electrophoresis, assessment of DNA purity, MTHFR C 677T gene mutation detection by PCR-RFLP method. Statistical analysis: Carried out by web based online SPSS tool. Results: The frequency of C677T genotype showed homozygous wild type CC (80%), heterozygous CT type (13.3%) and homozygous mutation TT type (6.67%) observed in males. Similarly from female’s homozygous wild type CC (86.6%), heterozygous type (13.3%), and homozygous type mutations TT (0%) was recorded. In couple control groups, we observed homozygous wild type CC (86.6%), heterozygous CT type (13.3%) and homozygous type mutations TT type (0%). Conclusion: We noticed a high frequency of MTHFR specifically T allele associated with paternal side.Therefore, the present study indicated the impact of paternal gene polymorphism of MTHFR C677T on screening in couples with recurrent pregnancy loss. PMID:25859445

  11. Identification of four novel mutations in severe methylenetetrahydrofolate reductase deficiency

    Microsoft Academic Search

    Leo AJ Kluijtmans; Udo Wendel; Erik MB Stevens; Lambert PWJ van den Heuvel; Frans JM Trijbels; Henk J Blom

    1998-01-01

    Severe methylenetetrahydrofolate reductase (MTHFR) deficiency is an inborn error of folate metabolism, and is inherited as an autosomal recessive trait. MTHFR is a key enzyme in folate-dependent remethylation of homocysteine, and reduces 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. Patients with this severe enzymatic deficiency are biochemically characterised by homocystinuria and hypomethioninaemia, and may suffer from neurological abnormalities, mental retardation and premature vascular disease.

  12. Seven novel mutations at the 5,10-methylenetetrahydrofolate reductase locus

    SciTech Connect

    Goyette, P.; Frosst, P.; Rosenblatt, D.S.; Rozen, R. [McGill Univ., Montreal (Canada)

    1994-09-01

    5,10-methylenetetrahydrofolate reductase (MTHFR), a flavoprotein, catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a cofactor for methionine synthase in the methylation of homocysteine to methionine. Severe MTHFR deficiency, which causes homocysteinemia, is an autosomal recessive disorder with variable clinical features; developmental delay, perinatal death, mental retardation and asymptomatic individuals have been observed. A milder deficiency has been reported in patients with cardiovascular disease. We have recently described the isolation of a cDNA for MTHFR and the identification of 2 mutations in patients with severe MTHFR deficiency. We report here the characterization of 7 additional mutations at this locus: 5 missense mutations and 2 splicing mutations. Mutation analysis was performed by SSCP on PCR products generated either from reverse transcription-PCR of patients` total fibroblast RNA or from PCR of patients` genomic DNA. The 5 missense mutations are as follows: 1 Arg to Cys substitution in a hydrophilic segment proposed to be the hinge region that connects the catalytic and regulatory domains, 2 different Arg to Cys substitutions in 2 patients whose enzymatic thermolability is responsive to FAD, 1 Thr to Met substitution affecting an evolutionarily-conserved residue and a Pro to Leu substitution. The 2 splicing mutations affect the 5{prime} splice site and the 3{prime} splice site of 2 introns, respectively. The 5{prime} splice site mutation generates a 57 bp in-frame deletion of the RNA through the utilization of a cryptic 5{prime} splice site within the coding sequence. The identification of 9 mutations at this locus has allowed us to make preliminary correlations between genotype and phenotype and to contribute to a structure:function analysis of the enzyme.

  13. An MTHFR variant, homocysteine, and cardiovascular comorbidity in renal disease

    Microsoft Academic Search

    Elizabeth M. Wrone; James L. Zehnder; John M. Hornberger; Linda M. McCann; Norman S. Coplon; Stephen P. Fortmann

    2001-01-01

    An MTHFR variant, homocysteine, and cardiovascular comorbidity in renal disease.BackgroundIt is unclear whether total serum homocysteine (tHcy) and the C677T mutation of methylenetetrahydrofolate reductase (MTHFR) are associated with cardiovascular disease (CVD) in patients with end-stage renal disease (ESRD).MethodsA cross-sectional sample of 459 patients with ESRD on chronic dialysis was assessed to determine whether tHcy and the C677T mutation are associated

  14. Methylenetetrahydrofolate Reductase Polymorphisms Increase Risk of Esophageal Squamous Cell Carcinoma in a Chinese Population1

    Microsoft Academic Search

    Chunying Song; Deyin Xing; Wen Tan; Qingyi Wei; Dongxin Lin

    2001-01-01

    Methylenetetrahydrofolate reductase (MTHFR) plays a central role in folate metabolism that affects DNA methylation and synthesis. Because germ-line mutations at nucleotides 677 (C3 T) and 1298 (A3 C) in the MTHFR gene cause diminished enzyme activity, and aberrant DNA meth- ylation is oncogenic, we examined the relationship between these two MTHFR polymorphisms and susceptibility to esophageal squamous cell carcinoma (ESCC)

  15. Methylenetetrahydrofolate reductase (MTHFR) 677C>T gene polymorphism as a possible factor for reducing clinical severity of psoriasis

    PubMed Central

    Karabacak, Ercan; Aydin, Ersin; Ozcan, Omer; Dogan, Bilal; Gultepe, Mustafa; Cosar, Alpaslan; Muftuoglu, Tuba

    2014-01-01

    Methylenetetrahydrofolate reductase (MTHFR) is a crucial enzyme in homocysteine/methionine metabolism. It catalysis the formation of 5-methyltetrahydrofolate (5-methyl-THF), which is the methyl donor for synthesis of methionine from homocysteine (Hcy). Decreases in folate consumption due to MTHFR polymorphism may affect production rate of keratinocytes of which had faster reproduction rates with a continuous DNA turnover and this may affect the clinical picture of psoriasis. This study aimed to investigate correlation of C677T polymorphisms in the MTHFR gene with severity of psoriasis and to evaluate the status of plasma Hcy, folate and vitamin B12 levels in patient with chronic plaque psoriasis. The study included 60 patients with chronic plaque psoriasis. The C677T polymorphisms were genotyped using PCR (Qiagen). Psoriasis Area and Severity Index (PASI) score below 7 was defined as mild, between 7 and 12 as moderate, and above 12 as severe disease. There was a significant difference between the severity of disease classification (p<0.05) with respect to the C677T polymorphism in the MTHFR gene. Severe involvement (PASI score >12) was observed in 38.46% of wild type (CC), but only 12.50% of homozygote (TT) and 7.69% of heterozygote (CT) patients. Significant differences between gene polymorphism and Hcy levels were noted in TT and CT genotypes respectively (p=0.025 and p=0.040). Plasma Hcy, folate and vitamin B12 levels were not correlated with the PASI score. Our data indicate a possible correlation of MTHFR polymorphism with severity of psoriasis. PMID:24753765

  16. Altered protein phosphatase 2A methylation and Tau phosphorylation in the young and aged brain of methylenetetrahydrofolate reductase (MTHFR) deficient mice

    PubMed Central

    Sontag, Jean-Marie; Wasek, Brandi; Taleski, Goce; Smith, Josephine; Arning, Erland; Sontag, Estelle; Bottiglieri, Teodoro

    2014-01-01

    Common functional polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, a key enzyme in folate and homocysteine metabolism, influence risk for a variety of complex disorders, including developmental, vascular, and neurological diseases. MTHFR deficiency is associated with elevation of homocysteine levels and alterations in the methylation cycle. Here, using young and aged Mthfr knockout mouse models, we show that mild MTHFR deficiency can lead to brain-region specific impairment of the methylation of Ser/Thr protein phosphatase 2A (PP2A). Relative to wild-type controls, decreased expression levels of PP2A and leucine carboxyl methyltransferase (LCMT1) were primarily observed in the hippocampus and cerebellum, and to a lesser extent in the cortex of young null Mthfr?/? and aged heterozygous Mthfr+/? mice. A marked down regulation of LCMT1 correlated with the loss of PP2A/B? holoenzymes. Dietary folate deficiency significantly decreased LCMT1, methylated PP2A and PP2A/B? levels in all brain regions examined from aged Mthfr+/+ mice, and further exacerbated the regional effects of MTHFR deficiency in aged Mthfr+/? mice. In turn, the down regulation of PP2A/B? was associated with enhanced phosphorylation of Tau, a neuropathological hallmark of Alzheimer’s disease (AD). Our findings identify hypomethylation of PP2A enzymes, which are major CNS phosphatases, as a novel mechanism by which MTHFR deficiency and Mthfr gene-diet interactions could lead to disruption of neuronal homeostasis, and increase the risk for a variety of neuropsychiatric disorders, including age-related diseases like sporadic AD. PMID:25202269

  17. Methylenetetrahydrofolate reductase (MTHFR) and breast cancer risk: a nested-case-control study and a pooled meta-analysis

    Microsoft Academic Search

    Debora Macis; Patrick Maisonneuve; Harriet Johansson; Bernardo Bonanni; Edoardo Botteri; Simona Iodice; Barbara Santillo; Silvana Penco; Giacomo Gucciardo; Giuseppe D’Aiuto; Marco Rosselli del Turco; Marinella Amadori; Alberto Costa; Andrea Decensi

    2007-01-01

    Background  A reduced activity of methylenetetrahydrofolate reductase (MTHFR) due to frequent C677T polymorphism affects DNA synthesis,\\u000a repair and methylation and may be implicated in breast cancer risk.\\u000a \\u000a \\u000a \\u000a Methods  We conducted a nested case-control study within a phase III prevention trial of tamoxifen. After a median follow-up of 81.2 months,\\u000a 79 of the 5,408 hysterectomised women aged 35–70 years, who had received either tamoxifen 20 mg\\/day

  18. Study of MTHFR and MS polymorphisms as risk factors for NTD in the Italian population

    Microsoft Academic Search

    Patrizia De Marco; Maria Grazia Calevo; Anna Moroni; Lorenza Arata; Elisa Merello; Richard H. Finnell; Huiping Zhu; Luciano Andreussi; Armando Cama; Valeria Capra

    2002-01-01

    Homozygosity for the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene is a risk factor for neural tube defects (NTDs) in many populations, including Italians. Another common mutation on\\u000a the MTHFR gene, A1298C, has also been described as a risk mutation. Furthermore, several studies have suggested that a defective methionine\\u000a synthase (MS) enzyme could be a critical defect in folate-related

  19. Methylene tetrahydrofolate reductase (MTHFR) and nitric oxide synthase (ecNOS) genes and risks of peripheral arterial disease and coronary heart disease: Edinburgh artery study

    Microsoft Academic Search

    F. G. R Fowkes; A. J Lee; C. M Hau; A Cooke; J. M Connor; G. D. O Lowe

    2000-01-01

    Hyperhomocysteinaemia and reduced nitric oxide synthesis may each result in endothelial dysfunction predisposing to atherogenesis. Genetic variants of methylene tetrahydrofolate reductase (MTHFR) and endothelial nitric oxide synthase (ecNOS) influence homocysteine metabolism and nitric oxide synthesis, respectively and might thus be determinants of the risk of atherosclerotic disease. The aim of our study was to identify, in a general population sample,

  20. C677T (thermolabile alanine\\/valine) polymorphism in methylenetetrahydrofolate reductase (MTHFR): its frequency and impact on plasma homocysteine concentration in different European populations

    Microsoft Academic Search

    Vilmundur Gudnason; David Stansbie; Jeff Scott; Ann Bowron; Viviane Nicaud; Steve Humphries

    1998-01-01

    A common polymorphism has been described in the methylenetetrahydrofolate reductase (MTHFR) gene, substituting an alanine (A) for a valine (V), where the V allele results in a thermolabile enzyme with reduced activity. This polymorphism is easily detectable by PCR amplification and digestion with HinfI restriction enzyme. We describe the use of the MADGE high throughput genotyping system for rapid typing

  1. Two Mutations in the Caprine MTHFR 3'UTR Regulated by MicroRNAs Are Associated with Milk Production Traits

    PubMed Central

    Song, Yuxuan; Gao, Teyang; Lei, Yingnan; Cao, Binyun

    2015-01-01

    Background 5,10-Methylenetetrahydrofolate reductase (MTHFR) plays a central role in folate metabolism by irreversibly converting 5,10-methylenetetrahydrofolate to 5-methylenetetrahydrofolate, a predominant circulating form of folate. Folate is reportedly important for milk protein synthesis, and MTHFR may be a key regulatory point of folate metabolism for milk protein synthesis in mammary epithelial cells. Prior to this study, polymorphisms of the MTHFR gene were not associated with milk production traits from a breeding perspective. Single nucleotide polymorphisms (SNPs) at microRNA (miRNA) binding sites (miR-SNPs) can affect gene expression. This study aimed to identify the effects of miR-SNPs (g.2244A>G and g.2264A>G) in the caprine MTHFR 3' UTR on the milk production traits of dairy goats. Results Guanzhong dairy (GD, n = 325) goats were used to detect SNPs in the caprine MTHFR 3' UTR by DNA sequencing. Two novel SNPs (g.2244A>G and g.2264A>G) were identified in the said region. The homozygous haplotype A-G of the SNPs g.2244A>G and g.2264A>G was significantly associated with milk yield and milk protein levels in GD goats (P < 0.05). Functional assays indicated that the MTHFR 2244 A ? G substitution could increase the binding activity of hsa-miR-1266 with the MTHFR 3' UTR. The MTHFR 2264 A ? G substitution could decrease the binding activity of hsa-miR-616 with the MTHFR 3' UTR. In addition, we observed a significant increase in the MTHFR mRNA levels of homozygous haplotype A-G carriers relative to those of homozygous haplotype G-A carriers. These results indicated that both SNPs altered the MTHFR mRNA levels. These altered levels of MTHFR mRNA may account for the association of SNPs with milk production traits. Conclusions This study is the first to report that the g.2244A>G and g.2264A>G polymorphisms were associated with milk production traits in GD goats. Further investigations should explore the underlying miRNA-mediated mechanisms that are modified by the g.2244A>G and g.2264A>G SNPs. The current study evaluated these SNPs as potential genetic markers in goats, with potential applications in breeding programs. PMID:26186555

  2. The methylenetetrahydrofolate reductase (MTHFR) 677 C>T polymorphism increases the risk of developing chronic myeloid leukemia-a case-control study.

    PubMed

    B?nescu, Claudia; Iancu, Mihaela; Trifa, Adrian P; Macarie, Ioan; Dima, Delia; Dobreanu, Minodora

    2015-04-01

    The methylenetetrahydrofolate reductase (MTHFR) 677 C>T and 1298 A>C polymorphisms are associated with variations in folate levels, a phenomenon linked to the development of various malignancies. The aim of this study was to investigate the influence of the 677 C>T and 1298 A>C polymorphisms in the MTHFR gene on the risk of developing chronic myeloid leukemia (CML). Our study included 151 patients with CML and 305 controls. The MTHFR 677 C>T and 1298 A>C polymorphisms were investigated by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and allele-specific PCR techniques. The CT and TT genotypes of the MTHFR 677 C>T polymorphism were associated with an increased risk of developing CML (odds ratio (OR)?=?1.556, 95% confidence interval (CI)?=?1.017-2.381, p value?=?0.041, and OR?=?1.897, 95% CI?=?1.046-3.44, p value?=?0.035, respectively). No association was observed between the prognostic factors (blasts, basophils, additional chromosomal abnormalities, EUTOS score, Sokal and Hasford risk groups) and the MTHFR 677 C>T and 1298 A>C variant genotypes in CML patients. Our study shows that the MTHFR 677 C>T polymorphism is significantly associated with the risk of CML in Romanian patients. PMID:25510667

  3. MTHFR 677C/T and 1298A/C mutations and non-alcoholic fatty liver disease.

    PubMed

    Kasapoglu, Benan; Turkay, Cansel; Yalcin, Kadir Serkan; Kosar, Ali; Bozkurt, Alper

    2015-06-01

    Common genetic mutations encountered in folate metabolism may result in increased homocysteine (Hcy) levels. It has been reported that increased serum Hcy levels may affect the intracellular fat metabolism and may cause enhanced fatty infiltration in the liver resulting in non-alcoholic fatty liver disease (NAFLD). In total, 150 patients diagnosed with FLD by ultrasound examination and 136 healthy control patients that do not have any fatty infiltration in the liver were included in the study. Patients were grouped as mild (n = 88), moderate (n = 38) or severe (n = 24) according to the stage of fatty liver in ultrasound. Serum liver function tests, Hcy, folic acid and vitamin B12 levels of the patients were studied. The genetic MTHFR C677T and A1298C polymorphisms of the patients were also evaluated. Although there was no significant difference in vitamin B12 and folic acid levels, in the severe group, Hcy levels were significantly higher than that of control and mild groups (p<0.001). By contrast, there was no significant difference in heterozygote MTHFR 677C/T and 1298A/C mutations, both MTHFR 677C/T and MTHFR 1298A/C mutations were more common in NAFLD groups compared with the control patients (p<0.001). We have determined increased Hcy levels and increased prevalence of homozygote MTHFR 677C/T and MTHFR 1298A/C mutations in patients with NAFLD compared with healthy controls. Larger studies are warranted to clarify the etiological role of the MTHFR mutations and Hcy levels in FLD. PMID:26031974

  4. Association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism with ischemic stroke in the Eastern Chinese Han population.

    PubMed

    Lv, Q-Q; Lu, J; Sun, H; Zhang, J-S

    2015-01-01

    The association between the MTHFR genetic polymorphism and ischemic stroke has been reported by a number of investigators. However, the results have been controversial and conflicting. The aim of this study was to explore the association between the MTHFR variants C677T and A1298C and the risk of ischemic stroke in an Eastern Chinese Han population. A total of 199 patients with ischemic stroke and 241 controls were recruited. Genotyping of the MTHFR C677T and A1298C polymorphisms was carried out using the Taqman 7900HT Sequence Detection System. The overall estimates (odds ratio: OR) for the allele (C) and genotype (AC+CC) of the A1298C polymorphism were 1.57 [95% confidence interval (CI) = 1.16-2.10], and 2.36 (95%CI = 1.39-4.00), respectively, establishing significant association of the MTHFR A1298C polymorphism with ischemic stroke. In contrast, there were no statistically significant differences compared to controls between MTHFR C677T polymorphic variants in the association ischemic stroke risk. Furthermore, haplotype-based analysis demonstrated that compared with the C-677-A-1298 haplotype, the C-677-C-1298 and T-677-C-1298 haplotypes showed significant increased risk of ischemic stroke (OR = 1.56; 95%CI = 1.07- 2.2; P = 0.02; OR = 1.76; 95%CI = 1.17-2.65; P < 0.01, respectively). We concluded that the A1298C polymorphism and the haplotypes C-677-C-1298 and T-677-C-1298 in MTHFR might modulate the risk of ischemic stroke in the Eastern Chinese Han population. PMID:25966188

  5. Distribution of alleles of the methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism in familial spina bifida.

    PubMed

    Johnson, W G; Stenroos, E S; Heath, S C; Chen, Y; Carroll, R; McKoy, V V; Chatkupt, S; Lehner, T

    1999-12-22

    Spina bifida cystica (SB) is one of the most common and disabling of birth defects. Folic acid supplementation in mothers during the periconceptional period has been shown to prevent more than 70% of neural tube defects (NTD) including SB. However, the mechanism is unknown. We tested a series of multicase SB families in which 224 individuals were genotyped and a group of 215 unrelated unaffected (external) control individuals for association of SB with the T allele of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism that produces a heat-labile enzyme protein. The data were analyzed using first the transmission/disequilibrium test (TDT) and second a modified case-control study design with Monte Carlo sampling methods. No association of SB with the MTHFR T allele was found by either method. Presently, association between SB and the T allele has been found in four studies, a Dutch study, an Irish study, a North American study, and an Italian study. But no association was found in four other studies, a British study, a French study, a Turkish study, and a German study. A California population-based study found only modestly increased risk of SB with this allele that was not significant at the P < 0.05 level. The present study finds no evidence of the association. Only one other study, the German study, has used TDT analysis. The present study is the first to use a modified case-control study design with Monte Carlo sampling methods to test this association. Thus, it appears that the MTHFR T allele is a risk factor for SB in some populations but not others. Major genetic risk factors for folate-related SB remain to be found. PMID:10594879

  6. A retrospective comparative exploratory study on two Methylentetrahydrofolate Reductase (MTHFR) polymorphisms in esophagogastric cancer: the A1298C MTHFR polymorphism is an independent prognostic factor only in neoadjuvantly treated gastric cancer patients

    PubMed Central

    2014-01-01

    Background Methylentetrahydrofolate reductase (MTHFR) plays a major role in folate metabolism and consequently could be an important factor for the efficacy of a treatment with 5-fluorouracil. Our aim was to evaluate the prognostic and predictive value of two well characterized constitutional MTHFR gene polymorphisms for primarily resected and neoadjuvantly treated esophagogastric adenocarcinomas. Methods 569 patients from two centers were analyzed (gastric cancer: 218, carcinoma of the esophagogastric junction (AEG II, III): 208 and esophagus (AEG I): 143). 369 patients received neoadjuvant chemotherapy followed by surgery, 200 patients were resected without preoperative treatment. The MTHFR C677T and A1298C polymorphisms were determined in DNA from peripheral blood lymphozytes. Associations with prognosis, response and clinicopathological factors were analyzed retrospectively within a prospective database (chi-square, log-rank, cox regression). Results Only the MTHFR A1298C polymorphisms had prognostic relevance in neoadjuvantly treated patients but it was not a predictor for response to neoadjuvant chemotherapy. The AC genotype of the MTHFR A1298C polymorphisms was significantly associated with worse outcome (p?=?0.02, HR 1.47 (1.06-2.04). If neoadjuvantly treated patients were analyzed based on their tumor localization, the AC genotype of the MTHFR A1298C polymorphisms was a significant negative prognostic factor in patients with gastric cancer according to UICC 6th edition (gastric cancer including AEG type II, III: HR 2.0, 95% CI 1.3-2.0, p?=?0.001) and 7th edition (gastric cancer without AEG II, III: HR 2.8, 95% CI 1.5-5.7, p?=?0.003), not for AEG I. For both definitions of gastric cancer the AC genotype was confirmed as an independent negative prognostic factor in cox regression analysis. In primarily resected patients neither the MTHFR A1298C nor the MTHFR C677T polymorphisms had prognostic impact. Conclusions The MTHFR A1298C polymorphisms was an independent prognostic factor in patients with neoadjuvantly treated gastric adenocarcinomas (according to both UICC 6th or 7th definitions for gastric cancer) but not in AEG I nor in primarily resected patients, which confirms the impact of this enzyme on chemotherapy associated outcome. PMID:24490800

  7. Effect of Riboflavin Status on the Homocysteine-lowering Effect of Folate in Relation to the MTHFR (C677T) Genotype

    Microsoft Academic Search

    Stuart J. Moat; Pauline A. L. Ashfield-Watt; Hilary J. Powers; Robert G. Newcombe; Ian F. W. McDowell

    2003-01-01

    Background: Riboflavin (vitamin B2) is the precursor for FAD, the cofactor for methylenetetrahydrofolate reductase (MTHFR). MTHFR catalyzes the formation of 5-methyltetrahydrofolate, which acts as a methyl donor for homocysteine remethylation. Individuals with the MTHFR 677C3 T mutation have increased plasma total homocysteine (tHcy) concentrations, particularly in as- sociation with low folate status. It has been proposed that riboflavin may act

  8. Association of methylenetetrahydrofolate reductase (MTHFR) polymorphisms with genetic susceptibility to gastric cancer: a meta-analysis

    Microsoft Academic Search

    Elias Zintzaras

    2006-01-01

    To clarify the influence of MTHFR C677T and A1298C polymorphisms on gastric cancer (GC), a meta-analysis of eight case-control studies (1,584\\/2,785 cases\\/controls) was carried out. Overall, there was moderate heterogeneity among studies, and the C677T allele T was associated with a 27% increased risk of GC compared with C allele: the random effects (RE) OR (95% confidence interval in parenthesis)

  9. Association of PHB 1630 C>T and MTHFR 677 C>T polymorphisms with breast and ovarian cancer risk in BRCA1/2 mutation carriers: results from a multicenter study

    PubMed Central

    Jakubowska, A; Rozkrut, D; Antoniou, A; Hamann, U; Scott, R J; McGuffog, L; Healy, S; Sinilnikova, O M; Rennert, G; Lejbkowicz, F; Flugelman, A; Andrulis, I L; Glendon, G; Ozcelik, H; Thomassen, M; Paligo, M; Aretini, P; Kantala, J; Aroer, B; von Wachenfeldt, A; Liljegren, A; Loman, N; Herbst, K; Kristoffersson, U; Rosenquist, R; Karlsson, P; Stenmark-Askmalm, M; Melin, B; Nathanson, K L; Domchek, S M; Byrski, T; Huzarski, T; Gronwald, J; Menkiszak, J; Cybulski, C; Serrano, P; Osorio, A; Cajal, T R; Tsitlaidou, M; Benítez, J; Gilbert, M; Rookus, M; Aalfs, C M; Kluijt, I; Boessenkool-Pape, J L; Meijers-Heijboer, H E J; Oosterwijk, J C; van Asperen, C J; Blok, M J; Nelen, M R; van den Ouweland, A M W; Seynaeve, C; van der Luijt, R B; Devilee, P; Easton, D F; Peock, S; Frost, D; Platte, R; Ellis, S D; Fineberg, E; Evans, D G; Lalloo, F; Eeles, R; Jacobs, C; Adlard, J; Davidson, R; Eccles, D; Cole, T; Cook, J; Godwin, A; Bove, B; Stoppa-Lyonnet, D; Caux-Moncoutier, V; Belotti, M; Tirapo, C; Mazoyer, S; Barjhoux, L; Boutry-Kryza, N; Pujol, P; Coupier, I; Peyrat, J-P; Vennin, P; Muller, D; Fricker, J-P; Venat-Bouvet, L; Johannsson, O Th; Isaacs, C; Schmutzler, R; Wappenschmidt, B; Meindl, A; Arnold, N; Varon-Mateeva, R; Niederacher, D; Sutter, C; Deissler, H; Preisler-Adams, S; Simard, J; Soucy, P; Durocher, F; Chenevix-Trench, G; Beesley, J; Chen, X; Rebbeck, T; Couch, F; Wang, X; Lindor, N; Fredericksen, Z; Pankratz, V S; Peterlongo, P; Bonanni, B; Fortuzzi, S; Peissel, B; Szabo, C; Mai, P L; Loud, J T; Lubinski, J

    2012-01-01

    Background: The variable penetrance of breast cancer in BRCA1/2 mutation carriers suggests that other genetic or environmental factors modify breast cancer risk. Two genes of special interest are prohibitin (PHB) and methylene-tetrahydrofolate reductase (MTHFR), both of which are important either directly or indirectly in maintaining genomic integrity. Methods: To evaluate the potential role of genetic variants within PHB and MTHFR in breast and ovarian cancer risk, 4102 BRCA1 and 2093 BRCA2 mutation carriers, and 6211 BRCA1 and 2902 BRCA2 carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2 (CIMBA) were genotyped for the PHB 1630 C>T (rs6917) polymorphism and the MTHFR 677 C>T (rs1801133) polymorphism, respectively. Results: There was no evidence of association between the PHB 1630 C>T and MTHFR 677 C>T polymorphisms with either disease for BRCA1 or BRCA2 mutation carriers when breast and ovarian cancer associations were evaluated separately. Analysis that evaluated associations for breast and ovarian cancer simultaneously showed some evidence that BRCA1 mutation carriers who had the rare homozygote genotype (TT) of the PHB 1630 C>T polymorphism were at increased risk of both breast and ovarian cancer (HR 1.50, 95%CI 1.10–2.04 and HR 2.16, 95%CI 1.24–3.76, respectively). However, there was no evidence of association under a multiplicative model for the effect of each minor allele. Conclusion: The PHB 1630TT genotype may modify breast and ovarian cancer risks in BRCA1 mutation carriers. This association need to be evaluated in larger series of BRCA1 mutation carriers. PMID:22669161

  10. Molecular genetic analysis in mild hyperhomocysteinemia: A common mutation in the methylenetetrahydrofolate reductase gene is a genetic risk factor for cardiovascular disease

    SciTech Connect

    Kluijtmans, L.A.J.; Heuvel, L.P.W.J. van den; Stevens, E.M.B. [Univ. Hospital Nijmegen (Netherlands)] [and others

    1996-01-01

    Mild hyperhomocysteinemia is an established risk factor for cardiovascular disease. Genetic aberrations in the cystathionine P-synthase (CBS) and methylenetetrahydrofolate reductase (MTHFR) genes may account for reduced enzyme activities and elevated plasma homocysteine levels. In 15 unrelated Dutch patients with homozygous CBS deficiency, we observed the 833T{yields}C (1278T) mutation in 50% of the alleles. Very recently, we identified a common mutation (677C{yields}T; A{yields}V) in the MTHFR gene, which, in homozygous state, is responsible for the thermolabile phenotype and which is associated with decreased specific MTHFR activity and elevated homocysteine levels. We screened 60 cardiovascular patients and 111 controls for these two mutations, to determine whether these mutations are risk factors for premature cardiovascular disease. Heterozygosity for the 833T{yields}C mutation in the CBS gene was observed in one individual of the control group but was absent in patients with premature cardiovascular disease. Homozygosity for the 677C-{yields}T mutation in the MTHFR gene was found in 9 (15%) of 60 cardiovascular patients and in only 6 ({approximately}5%) of 111 control individuals (odds ratio 3.1 [95% confidence interval 1.0-9.21]). Because of both the high prevalence of the 833T-{yields}C mutation among homozygotes for CBS deficiency and its absence in 60 cardiovascular patients, we may conclude that heterozygosity for CBS deficiency does not appear to be involved in premature cardiovascular disease. However, a frequent homozygous mutation in the MTHFR gene is associated with a threefold increase in risk for premature cardiovascular disease. 35 refs., 3 figs., 1 tab.

  11. Cerebral Venous Thrombosis and Livedo Reticularis in a Case with MTHFR 677TT Homozygote

    PubMed Central

    Lee, Jee-Young

    2006-01-01

    Hyperhomocysteinemia associated with methylene terahydrofolate reductase (MTHFR) mutation can be a risk factor for idiopathic cerebral venous thrombosis. We describe the first case of MTHFR 677TT homozygote with cerebral venous thrombosis and livedo reticularis. A 45-year-old man presented with seizures and mottled-like skin lesions, that were aggravated by cold temperature. Hemorrhagic infarct in the right frontoparietal area with superior sagittal sinus thrombosis was observed. He had hyperhomocysteinemia, low plasma folate level, and MTHFR 677TT homozygote genotype, which might be associated with livedo reticularis and increase the risk for cerebral venous thrombosis. PMID:20396498

  12. Methylenetetrahydrofolate reductase polymorphism and pre-eclampsia

    Microsoft Academic Search

    S Sohda; T Arinami; H Hamada; N Yamada; H Hamaguchi; T Kubo

    1997-01-01

    A common missense mutation in the methylenetetrahydrofolate reductase (MTHFR) gene, a C to T substitution at nucleotide 677, is responsible for reduced MTHFR activity and associated with modestly increased plasma homocysteine concentrations. Since underlying maternal vascular disease increases the risk of pre-eclampsia, we had the working hypothesis that pre-eclampsia patients would have an increased T677 allele frequency compared with controls.

  13. A COMMON POLYMORPHISM IN THE METHYLENETETRAHYDROFOLATE REDUCTASE (MTHFR) GENE IS ASSOCIATED WITH QUANTITATIVE ULTRASOUND IN THOSE WITH LOW PLASMA FOLATE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study of a polymorphism in the MTHFR gene, plasma folate, and bone phenotypes in 1632 individuals revealed that the genotype effect on BMD and quantitative ultrasound was dependent on the level of folate. Our findings support the hypothesis that the association between an MTHFR polymorphism and bo...

  14. Plasma Homocyst(e)ine Concentration, But Not MTHFR Genotype, Is Associated With Variation in Carotid Plaque Area

    Microsoft Academic Search

    J. David Spence; M. Rene Malinow; Peter A. Barnett; Ali J. Marian; David Freeman; Robert A. Hegele

    Background and Purpose—Elevated plasma homocyst(e)ine (H(e)) concentration is associated with premature athero- sclerosis. A common cause of elevated plasma H(e) concentration is a thermolabile mutation (677T) in the gene encoding methylenetetrahydrofolate reductase (MTHFR). We sought to determine whether plasma H(e) concentration or MTHFR genotype would be more strongly associated with carotid plaque area (CPA), a potential intermediate phenotype of atherosclerosis.

  15. Elevated total plasma homocysteine and 667C{r_arrow}T mutation of the 5,10-methylenetetrahydrofolate reductase gene in thrombotic vascular disease

    SciTech Connect

    De Franchis, R.; Sebastio, G.; Andria, G. [Universita Federico II, Naples (Italy)] [and others

    1996-07-01

    Moderate elevation of total plasma homocysteine (tHcy) has been reported as an independent risk factor for thrombotic vascular disease, a well-known multifactorial disorder. Possible genetic causes of elevated tHcy include defects of the sulfur-containing amino acids metabolism due to deficiencies of cystathionine {Beta}-synthase, of 5,10-methylenetetrahydrofolate reductase (MTHFR), and of the enzymes of cobalamin metabolism. An impaired activity of MTHFR due to a thermolabile form of the enzyme has been observed in {le}28% of hyperhomocysteinemic patients with premature vascular disease. More recently, the molecular basis of such enzymatic thermolability has been related to a common mutation of the MTHFR gene, causing a C-to-T substitution at nt 677 (677C{r_arrow}T). This mutation was found in 38% of unselected chromosomes from 57 French Canadian individuals. The homozygous state for the mutation was present in 12% of these subjects and correlated with significantly elevated tHcy. Preliminary evidence indicates that the frequency of homozygotes for the 677C{r_arrow}T mutation may vary significantly in populations from different geographic areas. 5 refs., 2 tabs.

  16. Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is associated with osteoporotic vertebral fractures, but is a weak predictor of BMD

    Microsoft Academic Search

    Morten M. Villadsen; Mathias H. Bünger; Mette Carstens; Liselotte Stenkjær; Bente L. Langdahl

    2005-01-01

    Osteoporosis is a common disease with a strong genetic component. Linkage studies have suggested linkage between BMD and loci on chromosome 1. The MTHFR gene is located on chromosome 1. MTHFR catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methylenetetrahydrofolate, which is used for homocysteine methylation to methionine. The rare genotype (TT) of the C677T polymorphism has previously been demonstrated to be

  17. Hyperbaric oxygen therapy in branch retinal artery occlusion in a 15-year-old boy with methylenetetrahydrofolate reductase mutation.

    PubMed

    Celebi, Ali Riza Cenk; Kadayifcilar, Sibel; Eldem, Bora

    2015-01-01

    Purpose. To report the efficacy of hyperbaric oxygen (HBO) therapy in a case of branch retinal artery occlusion (BRAO) in a 15-year-old boy. Methods. We report a 15-year-old boy with sudden loss of vision due to BRAO. Examination included laboratory evaluation for systemic risk factors. Follow-up exams included visual acuity, fundus examination, fundus fluorescein angiography, and visual field testing. HBO therapy was employed for treatment. Results. Medical history was positive for isolated glucocorticoid deficiency. Laboratory evaluation disclosed hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR) mutation. The visual acuity 0.05 at presentation improved to 0.8 after 20 days of HBO therapy. There was no change on visual fields. Conclusion. In this pediatric case, HBO therapy was useful in the treatment of BRAO. PMID:25722905

  18. Molecular beacons: a new approach for semiautomated mutation analysis

    Microsoft Academic Search

    Belinda A. J. Giesendorf; Jacqueline A. M. Vet; Sanjay Tyagi; Ewald J. M. G. Mensink; Frans J. M. Trijbels; Henk J. Blom

    Molecular beacons are oligonucleotide probes that be- come fluorescent upon hybridization. We designed molecular beacons to detect a point mutation in the methylenetetrahydrofolate reductase (MTHFR) gene, a mutation that has been related to an increased risk for cardiovascular disease and neural tube defects. The application of molecular beacons enables fast, semi- automated, accurate mutation detection. Moreover, the procedure is performed

  19. 5,10 Methylenetetrahydrofolate reductase genetic polymorphism as a risk factor for neural tube defects

    Microsoft Academic Search

    C. Y. Ou; V. K. Brown; M. J. Khoury

    1996-01-01

    Persons with a thermolabile form of the enzyme 5,10 methylenetetrahydrofolate reductase (MTHFR) have reduced enzyme activity and increased plasma homocysteine which can be lowered by supplemental folic acid. Thermolability of the enzyme has recently been shown to be caused by a common mutation (677C{sup â}T) in the MTHFR gene. We studied 41 fibroblast cultures from NTD-affected fetuses and compared their

  20. Heterogeneity in the prevalence of methylenetetrahydrofolate reductase gene polymorphisms in women of different ethnic groups

    Microsoft Academic Search

    Setareh Torabian Esfahani; Edward A Cogger; Marie A Caudill

    2003-01-01

    Objective To determine the prevalence of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms in women of different ethnic groups and to relate these common mutations to plasma homocysteine, red cell folate, and serum folate. Design A one-time fasting blood sample was obtained for MTHFR genotype (C677T and A1298C) determinations (n=433). Serum folate, red cell folate, and homocysteine analyses were performed in nonfolic

  1. Association of the C677T polymorphism in the MTHFR gene with breast and\\/or ovarian cancer risk in Jewish women

    Microsoft Academic Search

    R Gershoni-Baruch; E Dagan; D Israeli; L Kasinetz; E Kadouri; E Friedman

    2000-01-01

    The C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with reduced enzyme activity, hyperhomocysteinaemia and increased risk for atherosclerosis in homozygotes. We examined the frequency of this mutation and its association with disease pattern in 491 Jewish women with either sporadic (n=355; 72%) or hereditary (n=136; 28%) breast and\\/or ovarian cancer and in 69 asymptomatic BRCA1\\/2 mutation carriers,

  2. Children With Stroke: Polymorphism of the MTHFR Gene, Mild Hyperhomocysteinemia, and Vitamin Status

    Microsoft Academic Search

    Esther Cardo; Eugènia Monrós; Catrina Colomé; Rafael Artuch; Jaume Campistol; Mercè Pineda; M. Antònia Vilaseca

    2000-01-01

    The aim of this study was to investigate a possible association among the thermolabile polymorphism, nucleotide 677 cytosine to thymidine point mutation (677 C?T) of the methylenetetrahydrofolate reductase (MTHFR) gene, hyperhomocysteinemia, serum folate, vitamins B12 and B6, and stroke in children. Allele and genotype frequencies for the 677 C?T polymorphism in 21 children with stroke and 28 healthy children of

  3. Livedoid vasculopathy in a patient with lupus anticoagulant and MTHFR mutation: treatment with low-molecular-weight heparin.

    PubMed

    Abou Rahal, Jihane; Ishak, Rim S; Otrock, Zaher K; Kibbi, Abdul-Ghani; Taher, Ali T

    2012-11-01

    Livedoid vasculopathy is characterized by painful purpuric lesions on the extremities which frequently ulcerate and heal with atrophic scarring. For many years, livedoid vasculopathy has been considered to be a primary vasculitic process. However, there has been evidence considering livedoid vasculopathy as an occlusive vasculopathy due to a hypercoagulable state. We present the case of livedoid vasculopathy in a 21-year-old female who had been suffering of painful lower extremity lesions of 3 years duration. The patient was found to be lupus anticoagulant positive and homozygous for methylenetetrahydrofolate reductase C677T mutation. The patient was successfully treated with low-molecular-weight heparin. PMID:22592843

  4. Head and Neck Cancer Susceptibility: A Genetic Marker in the Methylenetetrahydrofolate Reductase Gene

    Microsoft Academic Search

    Nelofar Kureshi; Shehzad Ghaffar; Sammer Siddiqui; Iftikhar Salahuddin; Philippe M. Frossard

    2004-01-01

    Progress in the elucidation of molecular genetic changes that lead to the development of tumors should soon bring novel diagnostic and therapeutic procedures into clinical practice. In this respect, methylenetetrahydrofolate reductase (MTHFR) plays a central role in folate metabolism that affects DNA methylation and synthesis. DNA methylation is an epigenetic feature that influences cellular development and function. Germ line mutation

  5. Methylenetetrahydrofolate Reductase 677C.T and Methionine Synthase 2756A.G Mutations: No Impact on Survival, Cognitive Functioning, or Cognitive Decline in Nonagenarians

    Microsoft Academic Search

    Lise Bathum; Jacob von Bornemann Hjelmborg; Lene Christiansen; Matt McGue; Bernard Jeune; Kaare Christensen

    Background. Several reports have shown an association between homocysteine, cognitive functioning, and survival among the oldest-old. Two common polymorphisms in the genes coding for methylenetetrahydrofolate reductase (MTHFR 677C.T) and methionine synthase (MTR 2756A.G) have an impact on plasma homocysteine level. Methods. We examined the effect of the MTHFR 677C.T and MTR 2756A.G genotypes on baseline cognitive functioning, cognitive decline over

  6. Frequency of the Methylenetetrahydrofolate REDUCTASE 677CT and 1298AC mutations in an Iranian Turkish female population

    PubMed Central

    BAGHERI, Morteza; ABDI RAD, Isa

    2010-01-01

    ABSTRACT Introduction: Gene-environmental interactions in the pathway of folate metabolism influence greatly the embryonic development. Individual specific MTHFR 677C/T and 1298A/C mutations are known as risk factors for predisposition to human disorders. Therefore, we studied the frequencies of the MTHFR 677CT and 1298AC mutations in a female general population from Iranian Azeri Turkish. Material and methods: We studied 108 unrelated women from Iranian Azeri Turkish general population. Genomic DNA was extracted using standard procedure. The MTHFR 677CT and 1298AC mutations determined by PCR-RFLP method. Outcomes: The frequencies (percent) at position 677 for C and T alleles were 159(74%), 57(26%), and for CC, CT, and TT genotypes were 59(54.6%), 41(38%), and 8(7.41%) respectively. The frequencies (percent) at position 1298 for A and C alleles were 136(63%), 80(37%), and for AA, AC, and CC genotypes were 43(39.8%), 50(46.3%), and 15(13.9%) respectively. Conclusions: The frequency of MTHFR 677 C and T alleles were 0.74 and 0.26 while that of MTHFR 1298 A and C alleles were 0.63 and 0.37 in present study, respectively. This is the first report in its own kind in Iranian Azeri Turkish women. PMID:21977149

  7. Identification of six methylenetetrahydrofolate reductase ( MTHFR) genotypes resulting from common polymorphisms: impact on plasma homocysteine levels and development of coronary artery disease

    Microsoft Academic Search

    Christian Meisel; Ingolf Cascorbi; Thomas Gerloff; Verena Stangl; Michael Laule; Joachim M. Muller; Klaus D. Wernecke; Gert Baumann; Ivar Roots; Karl Stangl

    2001-01-01

    Although three common MTHFR polymorphisms (C677T, A1298C, T1317C) have been reported, only polymorphism C677T has been investigated intensively as a risk factor for coronary artery disease (CAD). We investigated polymorphism frequencies, allelic associations and the effect of the resulting MTHFR genotypes on total plasma homocysteine (tHcy) levels and on coronary risk in a case-control study with 1000 angiographically confirmed Middle-European

  8. Polymorphisms in the methylenetetrahydrofolate reductase gene are associated with susceptibility

    E-print Network

    California at Berkeley, University of

    ,10-methylenetetrahydro- folate reductase (MTHFR). A common 677 C 3 T polymorphism in the MTHFR gene results in thermolability and reduced MTHFR activity that decreases the pool of methylTHF and increases the pool of methyleneTHF. Recently, another polymorphism in MTHFR (1298 A 3 C) has been identified that also results

  9. A Common Variant in Methionine Synthase Reductase Combined with Low Cobalamin (Vitamin B 12) Increases Risk for Spina Bifida

    Microsoft Academic Search

    Aaron Wilson; Robert Platt; Qing Wu; Daniel Leclerc; Benedicte Christensen; Hong Yang; Roy A. Gravel; Rima Rozen

    1999-01-01

    Impairment of folate and cobalamin (vitamin B12) metabolism has been observed in families with neural tube defects (NTDs). Genetic variants of enzymes in the homocysteine remethylation pathway might act as predisposing factors contributing to NTD risk. The first polymorphism linked to increased NTD risk was the 677C?T mutation in methylenetetrahydrofolate reductase (MTHFR). We now report a polymorphism in methionine synthase

  10. C677T mutation in the 5,10-MTHFR gene and risk of Down syndrome in Italy

    Microsoft Academic Search

    Liborio Stuppia; Valentina Gatta; Anna Rita Gaspari; Ivana Antonucci; Elisena Morizio; Giuseppe Calabrese; Giandomenico Palka

    2002-01-01

    The C677T polymorphism of the MTHFR gene has been associated to maternal risk of Down syndrome, due to the detection of an higher prevalence of the T allele among mothers of children with trisomy 21, compared to control mothers. In order to confirm this association, we studied the presence of the C677T in 64 mothers of Down syndrome children and

  11. Evaluation of Gestational Diabetes Mellitus Risk in South Indian Women Based on MTHFR (C677T) and FVL (G1691A) Mutations

    PubMed Central

    Khan, Imran Ali; Shaik, Noor Ahmad; Kamineni, Vasundhara; Jahan, Parveen; Hasan, Qurratulain; Rao, Pragna

    2015-01-01

    We aimed to scrutinize the extent to which single amino acid substitutions in the MTHFR and factor V Leiden (FVL) genes affect the risk of gestational diabetes mellitus (GDM) in pregnant women of South Indian descendant. This case–control study was implemented once the ethical approval has been obtained. Overall, 237 women were recruited in this study: 137 had been diagnosed with GDM and the remaining 100 women were used as normal controls or non-GDM. The diagnosis of GDM was confirmed with biochemical analysis, i.e., GCT and oral glucose tolerance tests. Five milliliters of peripheral blood was collected and used for biochemical and molecular analyses. DNA was isolated, and genotyping for MTHFR (C677T) and FVL (G1691A) mutations was performed using PCR–RFLP. FVL (G1691A) locus was not polymorphic in the investigated sample. There was no significant difference in the allele and genotype frequencies of C677T polymorphism between GDM and non-GDM women (p?=?0.8892). PMID:26000264

  12. A Hypomethylating Variant of MTHFR, 677C.T, Blunts the Neural Response to Errors in Patients with

    E-print Network

    Manoach, Dara S.

    A Hypomethylating Variant of MTHFR, 677C.T, Blunts the Neural Response to Errors in Patients in methylenetetrahydrofolate reductase (MTHFR 677C.T, rs1801133) that increases risk for schizophrenia and that has been specifically associated with increased perseverative errors among patients. MTHFR is a key regulator

  13. MTHFR genotypes and breast cancer survival after surgery and chemotherapy: a report from the Shanghai Breast Cancer Study

    Microsoft Academic Search

    Martha J. Shrubsole; Xiao Ou Shu; Zhi Xian Ruan; Qiuyin Cai; Hui Cai; Qi Niu; Yu-Tang Gao; Wei Zheng

    2005-01-01

    Summary  Methylenetetrahydrofolate reductase (MTHFR) regulates the intracellular folates pool for DNA synthesis and methylation. Sequence variations in MTHFR (nucleotides 677 (CT) and 1298 (AC)) result in allozymes with decreased activity. The 677TT genotype is associated with increased toxicity of methotrexate and increased clinical response to 5-fluorouracil in treatment of cancers including breast cancer. We evaluated MTHFR genotypes and breast cancer survival

  14. Relations between molecular and biological abnormalities in 11 families from siblings affected with methylenetetrahydrofolate reductase deficiency

    Microsoft Academic Search

    Carole Tonetti; Jean-Marie Saudubray; Bernard Echenne; Pierre Landrieu; Stéphane Giraudier; Jacqueline Zittoun

    2003-01-01

    Methylenetetrahydrofolate reductase (MTHFR) deficiency is an autosomal recessive disorder resulting in elevated homocysteine levels in plasma and urine. MTHFR catalyses the reduction of methylenetetrahydrofolate to methyltetrahydrofolate, a cofactor for homocysteine remethylation to methionine. MTHFR deficiency may be diagnosed from infancy to adulthood with a broad spectrum of clinical symptoms. A molecular analysis of the MTHFR gene combined with an assessment

  15. Mthfr gene ablation enhances susceptibility to arsenic prenatal toxicity

    PubMed Central

    Wlodarczyk, Bogdan J.; Zhu, Huiping; Finnell, Richard H.

    2014-01-01

    Background In utero exposure to arsenic is known to adversely affect reproductive outcomes. Evidence of arsenic teratogenicity vary widely and depend on individual genotypic differences in sensitivity to As. In this study, we investigated the potential interaction between 5,10-methylenetetrahydrofolate reductase (Mthfr) genotype and arsenic embryotoxicity using the Mthfr knockout mouse model. Methods Pregnant dams were treated with sodium arsenate, and reproductive outcomes including: implantation, resorption, congenital malformation and fetal birth weight were recorded at E18.5. Results When the dams in Mthfr+/? x Mthfr+/? matings were treated with 7.2mg/kg As, the resorption rate increased to 43.4%, from a background frequency of 7.2%. The As treatment also induced external malformations (40.9%) and significantly lowered the average fetal birth weight among fetuses, without any obvious toxic effect on the dam. When comparing the pregnancy outcomes resulting from different mating scenarios (Mthfr+/+ x Mthfr+/?, Mthfr+/? x Mthfr+/? and Mthfr?/? x Mthfr+/?) and arsenic exposure; the resorption rate showed a linear relationship with the number of null alleles (0, 1 or 2) in the Mthfr dams. Fetuses from nullizygous dams had the highest rate of external malformations (43%) and lowest average birth weight. When comparing the outcomes of reciprocal matings (nullizygote x wild-type versus wild-type x nullizygote) after As treatment, the null dams showed significantly higher rates of resorptions and malformations, along with lower fetal birth weights. Conclusions Maternal genotype contributes to the sensitivity of As embryotoxicity in the Mthfr mouse model. The fetal genotype, however, does not appear to affect the reproductive outcome after in utero As exposure. PMID:24384392

  16. Study on Environmental Causes and SNPs of MTHFR, MS and CBS Genes Related to Congenital Heart Disease

    PubMed Central

    Liu, Yan; Huang, Peng; Lin, Ning; Sun, Xiaoru; Yu, Rongbin; Zhang, Yuanyuan; Qin, Yuming; Wang, Lijuan

    2015-01-01

    Purpose Congenital heart diseases (CHD) are among the most common birth defects in China. Environmental causes and folate metabolism changes may alter susceptibility to CHD. The aim of this study is to evaluate the relevant risk-factors of children with CHD and their mothers. Methods 138 children with CHD and 207 normal children for controls were recruited. Their mothers were also enlisted in this study and interviewed following a questionnaire about their pregnant history and early pregnancy situation. Five single nucleotide polymorphisms (SNPs) in methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MS) and cystathionine ?-synthase (CBS) of mothers and children were genotyped. Results There were significant differences in the gender of children, occupation of mothers, family history with CHD, history of abortion, history of adverse pregnancy, early pregnancy health, fetus during pregnancy, pesticide exposure and drug exposure in CHD group and control group ( P < 0.05). Logistic regression analyses showed that after adjustment for above factors, MTHFR rs1801131 were significantly associated with their offspring CHD risk in mothers. Compared with the mothers whose MTHFR were rs1801131 AA and AC genotypes, the mothers who got a mutation of MTHFR rs1801131 CC genotypes had a 267% increase in risk of given birth of a CHD children (OR=3.67,95%CI=1.12-12.05). Meanwhile, MTHFR rs1801131 were significantly associated with CHD susceptibility in children (OR = 1.42, 95% CI = 1.00-2.44 in additive model). Conclusions Besides mothers’ social and fertility characteristics, our results suggested that the genetic variants in folate metabolism pathway might be one of the most related risk-factors of CHD. MTHFR rs1801131 were identified as loci in Chinese population that were involved in CHD. PMID:26035828

  17. Thermolabile MTHFR genotype and retinal vascular occlusive disease

    Microsoft Academic Search

    M Cahill; M Karabatzaki; C Donoghue; R Meleady; L A Mynett-Johnson; D Mooney; I M Graham; A S Whitehead; D C Shields

    2001-01-01

    BACKGROUNDRaised levels of total plasma homocysteine (tHcy) are associated with an increased risk of retinal vascular occlusive disease. A thermolabile form of a pivotal enzyme in homocysteine metabolism, methylenetetrahydrofolate reductase (MTHFR), has been associated with vascular occlusive disease and raised tHcy levels. The relation between thermolabile MTHFR genotype, tHcy, and retinal vascular occlusive disease has not been determined.METHODSA retrospective case-control

  18. MTHFR gene C677T polymorphism and type 2 diabetic nephropathy in Asian populations: a meta-analysis

    PubMed Central

    Chen, Haiyan; Wei, Fang; Wang, Lihua; Wang, Zhe; Meng, Jia; Jia, Lan; Sun, Guijiang; Zhang, Ruining; Li, Bo; Yu, Haibo; Pang, Haiyan; Bi, Xueqing; Dong, Hongye; Jiang, Aili; Wang, Lin

    2015-01-01

    Background: Many studies have suggested a correlation between the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and diabetic nephropathy (DN), but their results are inconclusive. Methods: To confirm this correlation, we performed a meta-analysis of 15 studies. The dichotomous data are presented as odds ratios (OR) with 95% confidence intervals (CI). Results: The results of this study suggested that the MTHFR 677 T allele was more likely to increase the risk of DN in Asian (OR = 1.466, 95% CI = 1.143-1.880, P = 0.003), West Asian (OR = 1.750, 95% CI = 1.150-2.664, P = 0.009), and Chinese populations (OR = 2.162, 95% CI = 1.719-2.719, P = 0.001), but not in East Asian or Japanese populations. The carriers of the MTHFR 677 T allele were associated with progression of DN in the “5-10 year duration” group, but not in the “> 10 year duration” group (OR = 2.187, 95% CI = 1.787-2.677, P = 0.001). Conclusion: Development of DN is associated with MTHFR C677T polymorphisms in Asian populations, especially in early type 2 diabetes.

  19. Maternal Supplementary Folate Intake, Methylenetetrahydrofolate Reductase (MTHFR) C677T and A1298C Polymorphisms and the Risk of Orofacial Cleft in Iranian Children

    PubMed Central

    Ebadifar, Asghar; KhorramKhorshid, Hamid Reza; Kamali, Koorosh; Salehi Zeinabadi, Mehdi; Khoshbakht, Tayyebeh; Ameli, Nazila

    2015-01-01

    Background: The purpose of this study was to describe the association of MTHFR gene single nucleotide polymorphisms (C677T and A1298C) and maternal supplementary folate intake with orofacial clefts in the Iranian population. Methods: In this case-control study, peripheral venous blood was taken from 65 patients with orofacial clefts and 215 unaffected controls for DNA extraction and kept in EDTA for further analysis. The genotyping was carried out using Polymerase Chain Reaction (PCR) followed by Restriction Fragment Length Polymorphism (RFLP) and gel electrophoresis. Data were analyzed using Chi square test and logistic regression tests. Results: Genotype frequencies of 677TT were reported to be 13.5 and 36.1% in controls and CL/P patients, respectively, which showed a significant difference compared to CC as reference (OR=4.118; 95% CI=1.997–8.492; p=0.001). Conversely, 1298CC with frequencies of 10.8 and 12.7% in controls and patients, respectively, showed no significant difference compared to AA (OR=2.359; 95% CI=0.792–7.023; p=0.123). Comparing patients whose mothers did not report the folate supplement intake during pregnancy, to controls, it was observed that lack of folate intake was a predisposing factor for having a child with oral clefts (OR=5/718, p=0.000). Conclusion: Children carrying the 677TT variant of the MTHFR gene may have an increased risk of CL/P. In addition, the finding that the risk associated with this allele was obviously higher when the mothers didn’t use folic acid, supports the hypothesis that folic acid may play a role in the etiology of CL/P. PMID:26140186

  20. Targeted insertion of two Mthfr promoters in mice reveals temporal- and tissue-specific regulation

    Microsoft Academic Search

    Laura Pickell; Qing Wu; Xiao-Ling Wang; Daniel Leclerc; Hana Friedman; Alan C. Peterson; Rima Rozen

    Methylenetetrahydrofolate reductase (MTHFR), a key enzyme in folate metabolism, synthesizes 5-methyltetrahydrofolate, the\\u000a main circulatory form of folate which is required for maintaining nontoxic levels of homocysteine and providing one-carbon\\u000a units for methylation. A common 677C ? T variant in MTHFR confers mild MTHFR deficiency and has been associated with a number of human disorders, including neural tube defects and\\u000a vascular disease. Two

  1. Association of the MTHFR A1298C Variant with Unexplained Severe Male Infertility

    Microsoft Academic Search

    Abdelmajid Eloualid; Omar Abidi; Majida Charif; Brahim El houate; Houda Benrahma; Noureddine Louanjli; Elbakkay Chadli; Maria Ajjemami; Abdelhamid Barakat; Anu Bashamboo; Ken McElreavey; Houria Rhaissi; Hassan Rouba

    2012-01-01

    The methylenetetrahydrofolate reductase (MTHFR) gene is one of the main regulatory enzymes involved in folate metabolism, DNA synthesis and remethylation reactions. The influence of MTHFR variants on male infertility is not completely understood. The objective of this study was to analyze the distribution of the MTHFR C677T and A1298C variants using PCR-Restriction Fragment Length Polymorphism (RFLP) in a case group

  2. Methylenetetrahydrofolate reductase: biochemical characterization and medical significance.

    PubMed

    Trimmer, Elizabeth E

    2013-01-01

    Methylenetetrahydrofolate reductase (MTHFR) catalyzes the reduction of 5,10-methylenetetrahydofolate (CH2-H4folate) to 5-methyltetrahydrofolate (CH3-H4folate). The enzyme employs a noncovalently-bound flavin adenine dinucleotide (FAD), which accepts reducing equivalents from NAD(P)H and transfers them to CH2-H4folate. The reaction provides the sole source of CH3-H4folate, which is utilized by methionine synthase in the synthesis of methionine from homocysteine. MTHFR plays a key role in folate metabolism and in the homeostasis of homocysteine; mutations in the enzyme lead to hyperhomocyst(e)inemia. A common C677T polymorphism in MTHFR has been associated with an increased risk for the development of cardiovascular disease, Alzheimer's disease, and depression in adults, and of neural tube defects in the fetus. The mutation also confers protection for certain types of cancers. This review presents the current knowledge of the enzyme, its biochemical characterization, and medical significance. PMID:23116396

  3. Renal transplantation experience in a patient with factor V Leiden homozygous, MTHFR C677T heterozygous, and PAI heterozygous mutation.

    PubMed

    Gülhan, Bora; Tavil, Betül; Gümrük, Fatma; Aki, Tuncay F; Topaloglu, Rezan

    2015-08-01

    Vascular complications are important causes of allograft loss in renal transplantation. A two and a half-month-old boy was diagnosed with posterior urethral valve and progressed to end-stage renal disease at eight yr of age. During the HD period, a central venous catheter was replaced three times for repeated thrombosis. The boy was found to be homozygous for FVL and heterozygous for both MTHFR (C677T) and PAI. At the age of 12, renal transplantation was performed from a deceased donor. Postoperative anticoagulation therapy was initiated with continuous intravenous administration of heparin at the dose of 10 IU/kg/h. HD was performed for the first three days. By the fourth day of transplantation, his urine output had increased gradually. Heparin infusion was continued for 18 days during hospitalization at the same dosage. Thereafter, he was discharged with LMWH. On the third month after transplantation, his serum creatinine level was 1.1 mg/dL and eGFR was 75.7 mL/min/1.73 m(2) . He has still been using LMWH, and his eGFR was 78.7 mL/min/1.73 m(2) eight months after transplantation. Postoperative low-dose heparin treatment is a safe strategy for managing a patient with multiple thrombotic risk factors. PMID:25996881

  4. Biological and clinical implications of the MTHFR C677T polymorphism

    Microsoft Academic Search

    Per Magne Ueland; Steinar Hustad; Jørn Schneede; Helga Refsum; Stein Emil Vollset

    2001-01-01

    The enzyme methylenetetrahydrofolate reductase (MTHFR) directs folate species either to DNA synthesis or to homocysteine (Hcy) remethylation. The common MTHFR C677T polymorphism affects the activity of the enzyme and hence folate distribution. Under conditions of impaired folate status, the homozygous TT genotype has been regarded as harmful because it is associated with a high concentration of plasma total Hcy, increased

  5. Mutations at Several Loci Cause Increased Expression of Ribonucleotide Reductase in Escherichia coli

    PubMed Central

    Feeney, Morgan Anne; Ke, Na

    2012-01-01

    Production of deoxyribonucleotides for DNA synthesis is an essential and tightly regulated process. The class Ia ribonucleotide reductase (RNR), the product of the nrdAB genes, is required for aerobic growth of Escherichia coli. In catalyzing the reduction of ribonucleotides, two of the cysteines of RNR become oxidized, forming a disulfide bond. To regenerate active RNR, the cell uses thioredoxins and glutaredoxins to reduce the disulfide bond. Strains that lack thioredoxins 1 and 2 and glutaredoxin 1 do not grow because RNR remains in its oxidized, inactive form. However, suppressor mutations that lead to RNR overproduction allow glutaredoxin 3 to reduce sufficient RNR for growth of these mutant strains. We previously described suppressor mutations in the dnaA and dnaN genes that had such effects. Here we report the isolation of new mutations that lead to increased levels of RNR. These include mutations that were not known to influence production of RNR previously, such as a mutation in the hda gene and insertions in the nrdAB promoter region of insertion elements IS1 and IS5. Bioinformatic analysis raises the possibility that IS element insertion in this region represents an adaptive mechanism in nrdAB regulation in E. coli and closely related species. We also characterize mutations altering different amino acids in DnaA and DnaN from those isolated before. PMID:22247510

  6. Mice deficient in methylenetetrahydrofolate reductase exhibit hyperhomocysteinemia and decreased methylation capacity, with neuropathology and aortic lipid deposition

    Microsoft Academic Search

    Zhoutao Chen; A C Karaplis; Susan L. Ackerman; Igor P. Pogribny; Stepan Melnyk; Cacan S Lussier; Moy Fong Chen; A Pai; S W John; R S Smith; T Bottiglieri; P Bagley; J Selhub; M A Rudnicki; S J James; R Rozen

    2001-01-01

    Hyperhomocysteinemia, a risk factor for cardiovascular disease, is caused by nutritional and\\/or genetic disruptions in homocysteine metabolism. The most common genetic cause of hyperhomocysteinemia is the 677C-->T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene. This variant, with mild enzymatic deficiency, is associated with an increased risk for neural tube defects and pregnancy complications and with a decreased risk for colon

  7. Alterations in intracellular deoxyribonucleotide levels of mutationally altered ribonucleotide reductases in Escherichia coli.

    PubMed Central

    Platz, A; Karlsson, M; Hahne, S; Eriksson, S; Sjöberg, B M

    1985-01-01

    Four recombinant plasmid clones (pPS305, pPS308, pPS317, and pPS319) coding for Escherichia coli ribonucleotide reductase have been characterized in vivo and in vitro. Each clone carried a different missense mutation affecting the B1 subunit. Measurements were made of deoxyribonucleoside triphosphate pools. Cells carrying the wild-type plasmid, pPS2, overproduced ribonucleotide reductase 10 to 20 times. As a consequence of this elevated enzyme level, the deoxyribonucleotide pools were approximately three times higher. All four mutant clones showed disturbed deoxyribonucleotide pools. The in vitro studies involved chromatography on affinity media, measurements of enzyme activity and allosteric regulation with a variety of substrates and effector molecules, and direct photoaffinity labeling in the presence of dTTP. Clones pPS305 and pPS308 were shown to code for catalytically defective enzymes, whereas clones pPS317 and pPS319 were shown to code for allosterically altered enzymes. The characterized missense mutations can thus be localized to areas involved in regulation of the substrate specificity or to the active site of protein B1. The alteration of the deoxyribonucleotide pools found in cells containing the allosterically defective clones pPS317 and pPS319 clearly demonstrated in vivo significance for the allosteric control of protein B1 in E. coli cells. PMID:3905766

  8. Novel mutator mutants of E. coli nrdAB ribonucleotide reductase: insight into allosteric regulation and control of mutation rates

    PubMed Central

    Ahluwalia, Deepti; Bienstock, Rachelle J.; Schaaper, Roel M.

    2012-01-01

    Ribonucleotide reductase (RNR) is the enzyme critically responsible for the production of the 5?-deoxynucleoside-triphosphates (dNTPs), the direct precursors for DNA synthesis. The dNTP levels are tightly controlled to permit high efficiency and fidelity of DNA synthesis. Much of this control occurs at the level of the RNR by feedback processes, but a detailed understanding of these mechanisms is still lacking. Using a genetic approach in the bacterium E. coli, a paradigm for the Class Ia RNRs, we isolated 23 novel RNR mutants displaying elevated mutation rates along with altered dNTP levels. The responsible amino-acid substitutions in RNR reside in three different regions: (i) the (d)ATP-binding activity domain, (ii) a novel region in the small subunit adjacent to the activity domain, and (iii) the dNTP-binding specificity site, several of which are associated with different dNTP pool alterations and different mutational outcomes. These mutants provide new insight into the precise mechanisms by which RNR is regulated and how dNTP pool disturbances resulting from defects in RNR can lead to increased mutation. PMID:22417940

  9. Insights into severe 5,10-methylenetetrahydrofolate reductase deficiency: molecular genetic and enzymatic characterization of 76 patients.

    PubMed

    Burda, Patricie; Schäfer, Alexandra; Suormala, Terttu; Rummel, Till; Bürer, Céline; Heuberger, Dorothea; Frapolli, Michele; Giunta, Cecilia; Sokolová, Jitka; Vlášková, Hana; Kožich, Viktor; Koch, Hans Georg; Fowler, Brian; Froese, D Sean; Baumgartner, Matthias R

    2015-06-01

    5,10-Methylenetetrahydrofolate reductase (MTHFR) deficiency is the most common inherited disorder of folate metabolism and causes severe hyperhomocysteinaemia. To better understand the relationship between mutation and function, we performed molecular genetic analysis of 76 MTHFR deficient patients, followed by extensive enzymatic characterization of fibroblasts from 72 of these. A deleterious mutation was detected on each of the 152 patient alleles, with one allele harboring two mutations. Sixty five different mutations (42 novel) were detected, including a common splicing mutation (c.1542G>A) found in 21 alleles. Using an enzyme assay in the physiological direction, we found residual activity (1.7%-42% of control) in 42 cell lines, of which 28 showed reduced affinity for nicotinamide adenine dinucleotide phosphate (NADPH), one reduced affinity for methylenetetrahydrofolate, five flavin adenine dinucleotide-responsiveness, and 24 abnormal kinetics of S-adenosylmethionine inhibition. Missense mutations causing virtually absent activity were found exclusively in the N-terminal catalytic domain, whereas missense mutations in the C-terminal regulatory domain caused decreased NADPH binding and disturbed inhibition by S-adenosylmethionine. Characterization of patients in this way provides a basis for improved diagnosis using expanded enzymatic criteria, increases understanding of the molecular basis of MTHFR dysfunction, and points to the possible role of cofactor or substrate in the treatment of patients with specific mutations. PMID:25736335

  10. Dietary intake of folate and co-factors in folate metabolism, MTHFR polymorphisms, and reduced rectal cancer

    Microsoft Academic Search

    Maureen A. Murtaugh; Karen Curtin; Carol Sweeney; Roger K. Wolff; Richard Holubkov; Bette J. Caan; Martha L. Slattery

    2007-01-01

    Little is known about the contribution of polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR) and the folate metabolism pathway in rectal cancer alone. Data were from participants in a case–control study conducted\\u000a in Northern California and Utah (751 cases and 979 controls). We examined independent associations and interactions of folate,\\u000a B vitamins, methionine, alcohol, and MTHFR polymorphisms (MTHFR C677T and

  11. Direct selection for mutations affecting specific splice sites in a hamster dihydrofolate reductase minigene.

    PubMed Central

    Chen, I T; Chasin, L A

    1993-01-01

    A Chinese hamster cell line containing an extra exon 2 (50 bp) inserted into a single intron of a dihydrofolate reductase (dhfr) minigene was constructed. The extra exon 2 was efficiently spliced into the RNA, resulting in an mRNA that is incapable of coding for the DHFR enzyme. Mutations that decreased splicing of this extra exon 2 caused it to be skipped and so produced normal dhfr mRNA. In contrast to the parental cell line, the splicing mutants display a DHFR-positive growth phenotype. Splicing mutants were isolated from this cell line after treatment with four different mutagens (racemic benzo[c]phenanthrene diol epoxide, ethyl methanesulfonate, ethyl nitrosourea, and UV irradiation). By polymerase chain reaction amplification and direct DNA sequencing, we determined the base changes in 66 mutants. Each of the mutagens generated highly specific base changes. All mutations were single-base substitutions and comprised 24 different changes distributed over 16 positions. Most of the mutations were within the consensus sequences at the exon 2 splice donor, acceptor, and branch sites. The RNA splicing patterns in the mutants were analyzed by quantitative reverse transcription-polymerase chain reaction. The recruitment of cryptic sites was rarely seen; simple exon skipping was the predominant mutant phenotype. The wide variety of mutations that produced exon skipping suggests that this phenotype is the typical consequence of splice site damage and supports the exon definition model of splice site selection. A few mutations were located outside the consensus sequences, in the exon or between the branch point and the polypyrimidine tract, identifying additional positions that play a role in splice site definition. That most of these 66 mutations fell within consensus sequences in this near-saturation mutagenesis suggests that splicing signals beyond the consensus may consist of robust RNA structures. Images PMID:8417332

  12. Polymorphisms of 5,10-Methylenetetrahydrofolate Reductase and Cystathionine ?-Synthase Genes as a Risk Factor for Neural Tube Defects in Sétif, Algeria

    Microsoft Academic Search

    Bakhouche Houcher; Romyla Bourouba; Farida Djabi; Erkan Yilmaz; Nejat Akar

    2009-01-01

    Background: Neural tube defects (NTD) are severe congenital malformations due to a failure in neural tube formation at the beginning of pregnancy. The etiology of NTD is multifactorial, with environmental and genetic determinants. We suggest a study of gene-gene interactions regarding the possible association of NTD with specific mutations of 5,10-methylenetetrahydrofolate reductase (MTHFR) and cystathionine ?-synthase (CBS) genes. Patients and

  13. Novel Point Mutations in the Dihydrofolate Reductase Gene of Plasmodium vivax: Evidence for Sequential Selection by Drug Pressure

    Microsoft Academic Search

    Mallika Imwong; Sasithon Pukrittayakamee; Laurent Renia; Franck Letourneur; Jean-Paul Charlieu; Ubolsree Leartsakulpanich; Sornchai Looareesuwan; Nicholas J. White; Georges Snounou

    2003-01-01

    Mutations in the dihydrofolate reductase (dhfr) genes of Plasmodium falciparum and P. vivax are associated with resistance to the antifolate antimalarial drugs. P. vivax dhfr sequences were obtained from 55 P. vivax isolates (isolates Belem and Sal 1, which are established lines originating from Latin America, and isolates from patient samples from Thailand (n 44), India (n 5), Iran (n

  14. Impact of thrombophilic genes mutations on thrombosis risk in Egyptian nonmetastatic cancer patients.

    PubMed

    Wahba, Mona Ahmed; Ismail, Mona Ahmed; Saad, Abeer Attia; Habashy, Deena Mohamed; Hafeez, Zeinab Mohamed Abdel; Boshnak, Noha Hussein

    2015-04-01

    Venous thromboembolism (VTE) is a common complication in cancer patients. Several genetic risk factors related to thrombophilia are known; however, their contributions to thrombotic tendency in cancer patients have conflicting results. We aimed to determine the prevalence of factor V Leiden (FVL), prothrombin (PTH) G20210A and methylene tetrahydrofolate reductase (MTHFR) C677T gene polymorphisms in Egyptian nonmetastatic cancer patients and their influence on thrombosis risk in those patients. Factor V Leiden, PTH G20210A and MTHFR C677T polymorphisms were detected in 40 cancer patients with VTE (group 1) and 40 cancer patients with no evidence of VTE (group 2) by PCR-based DNA analysis. Factor V and MTHFR mutations were higher in group 1 than in group 2 (factor V heterozygous mutation: 20 vs. 7.5%, homozygous mutation: 10 vs. 2.5%; MTHFR heterozygous mutation: 40 vs. 25%, homozygous mutation 5 vs. 0%, respectively) (P?=?0.03). Mortality rate was higher in group 1 (75%) than in group 2 (25%; P?mutation (P?=?1). Mortality rate was higher in the presence of homozygous and heterozygous factor V mutation (100 and 82%, respectively) compared to the wild type (41%) (P?=?0.0006). Having any of the three studied gene mutations worsened the overall survival (P?=?0.0003). Cox regression proved that both thrombosis and presence of factor V mutation are independent factors affecting survival in cancer patients (P?MTHFR mutations and risk of VTE in Egyptian cancer patients. Thrombosis and presence of factor V mutation are independent factors that influence survival in those patients. PMID:25565385

  15. The association of p53 mutations and p53 codon 72, Her 2 codon 655 and MTHFR C677T polymorphisms with breast cancer in Northern Greece

    Microsoft Academic Search

    Theodora G. Kalemi; Alexandros F. Lambropoulos; Maria Gueorguiev; Sofia Chrisafi; Konstantinos T. Papazisis; Alexandros Kotsis

    2005-01-01

    The aim of this study was to explore a possible association between p53 codon 72, Her 2 codon 655 and MTHFR C677T polymorphisms and breast cancer in Northern Greece. We examined 42 women with breast cancer and 51 controls. A total of 42 women with breast cancer as well as healthy controls were investigated and results showed that p53 codon

  16. Transcobalamin and methionine synthase reductase mutated polymorphisms aggravate the risk of neural tube defects in humans

    Microsoft Academic Search

    R. M. Guéant-Rodriguez; C. Rendeli; B. Namour; L. Venuti; A. Romano; G. Anello; P. Bosco; R. Debard; P. Gérard; M. Viola; E. Salvaggio; J. L. Guéant

    2003-01-01

    The pathogenic mechanism of neural tube defects may involve genetic polymorphisms and nutritional factors related to homocysteine metabolism. We evaluated the association of polymorphisms of three genes affecting vitamin B12-dependent remethylation of homocysteine, transcobalamin (TC), methioninesynthase (MTR) and MTRreductase (MTRR), combined or not with methylenetetrahydrofolatereductase (MTHFR), with the risk of having neural tube defect in 40 children with spina bifida

  17. Effect of MTHFR 677C>T on plasma total homocysteine levels in renal graft recipients

    Microsoft Academic Search

    MANUELA FÖDINGER; GABRIELE WÖLFL; GOTTFRIED FISCHER; SUSANNE RASOUL-ROCKENSCHAUB; RAINER SCHMID; WALTER H. HORL; GERE SUNDER-PLASSMANN

    1999-01-01

    Effect of MTHFR 677C>T on plasma total homocysteine levels in renal graft recipients.BackgroundHyperhomocysteinemia is an established, independent risk factor for vascular disease morbidity and mortality. The 5,10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism C677T has been shown to result in increased total homocysteine concentrations on the basis of low folate levels caused by a decreased enzyme activity. The effect of this polymorphism

  18. Riboflavin Lowers Homocysteine in Individuals Homozygous for the MTHFR 677C3T Polymorphism

    Microsoft Academic Search

    Helene McNulty; Le Roy; C. Dowey; J. J. Strain; Adrian Dunne; Mary Ward; Anne M. Molloy; Liadhan B. McAnena; Joan P. Hughes; Mary Hannon-Fletcher; John M. Scott

    Background—Meta-analyses predict that a 25% lowering of plasma homocysteine would reduce the risk of coronary heart disease by 11% to 16% and stroke by 19% to 24%. Individuals homozygous for the methylenetetrahydrofolate reductase (MTHFR) 677C3T polymorphism have reduced MTHFR enzyme activity resulting from the inappropriate loss of the riboflavin cofactor, but it is unknown whether their typically high homocysteine levels

  19. Genotype and haplotype distributions of MTHFR 677C>T and 1298A>C single nucleotide polymorphisms: a meta-analysis

    Microsoft Academic Search

    Shuji Ogino; Robert B. Wilson

    2003-01-01

    .  ?Common single nucleotide polymorphisms (SNPs; 677C>T and 1298A>C) in the methylenetetrahydrofolate reductase gene (MTHFR) decrease the activity of the enzyme, leading to hyperhomocysteinemia, particularly in folate-deficient states. We calculate\\u000a herein the haplotype frequencies of the MTHFR 677 and 1298 polymorphisms in pooled general populations derived from published data. We selected 16 articles that provided\\u000a reliable data on combined MTHFR genotypes

  20. In Vitro Generation of Novel Pyrimethamine Resistance Mutations in the Toxoplasma gondii Dihydrofolate Reductase

    PubMed Central

    Reynolds, Mary G.; Oh, Jung; Roos, David S.

    2001-01-01

    Pyrimethamine is a potent inhibitor of dihydrofolate reductase and is widely used in the treatment of opportunistic infections caused by the protozoan parasite Toxoplasma gondii. In order to assess the potential role of dhfr sequence polymorphisms in drug treatment failures, we examined the dhfr-ts genes of representative isolates for T. gondii virulence types I, II, and III. These strains exhibit differences in their sensitivities to pyrimethamine but no differences in predicted dhfr-ts protein sequences. To assess the potential for pyrimethamine-resistant dhfr mutants to emerge, three drug-sensitive variants of the T. gondii dhfr-ts gene (the wild-type T. gondii sequence and two mutants engineered to reflect polymorphisms observed in drug-sensitive Plasmodium falciparum) were subjected to random mutagenesis and transfected into either wild-type T. gondii parasites or dhfr-deficient Saccharomyces cerevisiae under pyrimethamine selection. Three resistance mutations were identified, at amino acid residues 25 (Trp?Arg), 98 (Leu?Ser), and 134 (Leu?His). PMID:11257045

  1. Altered heme catabolism by heme oxygenase-1 caused by mutations in human NADPH cytochrome P450 reductase

    SciTech Connect

    Pandey, Amit V., E-mail: amit@pandeylab.org [Pediatric Endocrinology, Diabetology and Metabolism, Department of Clinical Research, University of Bern, Tiefenaustrasse 120c, CH-3004 Bern (Switzerland); Flueck, Christa E.; Mullis, Primus E. [Pediatric Endocrinology, Diabetology and Metabolism, Department of Clinical Research, University of Bern, Tiefenaustrasse 120c, CH-3004 Bern (Switzerland)] [Pediatric Endocrinology, Diabetology and Metabolism, Department of Clinical Research, University of Bern, Tiefenaustrasse 120c, CH-3004 Bern (Switzerland)

    2010-09-24

    Research highlights: {yields} Mutations in POR identified from patients lead to reduced HO-1 activities. {yields} POR mutation Y181D affecting FMN binding results in total loss of HO-1 activity. {yields} POR mutations A287P, C569Y and V608F, lost 50-70% activity. {yields} Mutations in FAD binding domain, R457H, Y459H and V492E lost all HO-1 activity. {yields} POR polymorphisms P228L, R316W, G413S, A503V and G504R have normal activity. -- Abstract: Human heme oxygenase-1 (HO-1) carries out heme catabolism supported by electrons supplied from the NADPH through NADPH P450 reductase (POR, CPR). Previously we have shown that mutations in human POR cause a rare form of congenital adrenal hyperplasia. In this study, we have evaluated the effects of mutations in POR on HO-1 activity. We used purified preparations of wild type and mutant human POR and in vitro reconstitution with purified HO-1 to measure heme degradation in a coupled assay using biliverdin reductase. Here we show that mutations in POR found in patients may reduce HO-1 activity, potentially influencing heme catabolism in individuals carrying mutant POR alleles. POR mutants Y181D, A457H, Y459H, V492E and R616X had total loss of HO-1 activity, while POR mutations A287P, C569Y and V608F lost 50-70% activity. The POR variants P228L, R316W and G413S, A503V and G504R identified as polymorphs had close to WT activity. Loss of HO-1 activity may result in increased oxidative neurotoxicity, anemia, growth retardation and iron deposition. Further examination of patients affected with POR deficiency will be required to assess the metabolic effects of reduced HO-1 activity in affected individuals.

  2. The thermolabile variant of MTHFR is associated with depression in the British Women's Heart and Health Study and a meta-analysis

    Microsoft Academic Search

    S J Lewis; D A Lawlor; G Davey Smith; R Araya; N Timpson; I N M Day; S Ebrahim

    2006-01-01

    Low dietary folate intake has been implicated as a risk factor for depression. However, observational epidemiological studies are plagued by problems of confounding, reverse causality and measurement error. A common polymorphism (C677T) in MTHFR is associated with methyltetrahydrofolate reductase (MTHFR) activity and circulating folate and homocysteine levels and offers insights into whether the association between low folate and depression is

  3. Methylenetetrahydrofolate reductase C677T polymorphism and predisposition towards esophageal squamous cell carcinoma in a German Caucasian and a northern Chinese population

    Microsoft Academic Search

    Jianhui Zhang; Rainer B. Zotz; Yan Li; Rui Wang; Sybille Kiel; Wolfgang A. Schulz; Denggui Wen; Zhifeng Chen; Liwei Zhang; Shijie Wang; Helmut E. Gabbert; Mario Sarbia

    2004-01-01

    Purpose Folate deficiency is considered to increase the risk of developing esophageal cancer. Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme involved in folate metabolism. A single C ? T substitution at nucleotide 677 of the MTHFR cDNA influences enzyme activity. The purpose of this study is to compare the association of the MTHFR C677T polymorphism with susceptibility to esophageal squamous

  4. Evaluation of the MTHFR C677T allele and the MTHFR gene locus in a German spina bifida population

    Microsoft Academic Search

    M. C. Koch; K. Stegmann; A. Ziegler; B. Schröter; A. Ermert

    1998-01-01

    A number of recent studies have demonstrated that the occurrence and recurrence risk of neural tube defects (NTD) is reduced\\u000a by folic acid supplementation before and during pregnancy. Epidemiological studies have shown low plasma folate and raised\\u000a plasma homocysteine in women with spina bifida aperta (SB) children suggesting an abnormal folate metabolism. The 5,10-methylenetetrahydrofolate\\u000a reductase (MTHFR) variant C677T, resulting in

  5. Association of von Willebrand Factor Activity with ACE I\\/D and MTHFR C677T Polymorphisms in Migrainecha

    Microsoft Academic Search

    GE Tietjen; NA Herial; C Utley; L White; S Yerga-Woolwine; B Joe

    2009-01-01

    Angiotensin-converting enzyme (ACE) insertion (I)\\/deletion (D) and methylene-tetrahydrofolate reductase (MTHFR) C677T polymorphisms are linked to endothelial dysfunction and to cerebral white matter lesions. Objectives of this study were to determine if ACE and MTHFR gene polymorphisms are associated with von Willebrand factor (vWF) activity, an endothelial dysfunction marker, and with a distinct headache phenotype. We enrolled 64 women (18–50 years

  6. Role of polymorphisms in MTHFR and MTHFD1 genes in the outcome of childhood acute lymphoblastic leukemia

    Microsoft Academic Search

    M Krajinovic; É Lemieux-Blanchard; S Chiasson; M Primeau; I Costea; A Moghrabi

    2004-01-01

    The central role of 5,10-methylenetetrahydrofolate reductase (MTHFR) and methylenetetrahydrofolate dehydrogenase (MTHFD1) in folate metabolism renders polymorphisms in genes encoding these enzymes potential modulators of therapeutic response to antifolate chemotherapeutics. The analysis of 201 children treated with methotrexate for childhood acute lymphoblastic leukemia (ALL) showed that patients with either the MTHFR T677A1298 haplotype or MTHFD1 A1958 variant had a lower probability

  7. Genetic Polymorphisms in MTHFR 677 and 1298, GSTM1 and T1, and Metabolism of Arsenic

    Microsoft Academic Search

    Craig Steinmaus; Lee E. Moore; Miriam Shipp; David Kalman; Omar A. Rey; Mary L. Biggs; Claudia Hopenhayn; Michael N. Bates; Shichun Zheng; John K. Wiencke; Allan H. Smith

    2007-01-01

    Methylation is the primary route of metabolism of inorganic arsenic in humans, and previous studies showed that interindividual differences in arsenic methylation may have important impacts on susceptibility to arsenic-induced cancer. To date, the factors that regulate arsenic methylation in humans are mostly unknown. Urinary arsenic methylation patterns and genetic polymorphisms in methylenetetrahydrofolate reductase (MTHFR) and glutathione S-transferase (GST) were

  8. Population- and Family-Based Studies Associate the "MTHFR" Gene with Idiopathic Autism in Simplex Families

    ERIC Educational Resources Information Center

    Liu, Xudong; Solehdin, Fatima; Cohen, Ira L.; Gonzalez, Maripaz G.; Jenkins, Edmund C.; Lewis, M. E. Suzanne; Holden, Jeanette J. A.

    2011-01-01

    Two methylenetetrahydrofolate reductase gene ("MTHFR") functional polymorphisms were studied in 205 North American simplex (SPX) and 307 multiplex (MPX) families having one or more children with an autism spectrum disorder. Case-control comparisons revealed a significantly higher frequency of the low-activity 677T allele, higher prevalence of the…

  9. A Promoter Mutation Causes Differential Nitrate Reductase Activity of Mycobacterium tuberculosis and Mycobacterium bovis

    PubMed Central

    Stermann, Marion; Sedlacek, Ludwig; Maass, Silvia; Bange, Franz-Christoph

    2004-01-01

    The recent publication of the genome sequence of Mycobacterium bovis showed >99.95% identity to M. tuberculosis. No genes unique to M. bovis were found. Instead numerous single-nucleotide polymorphisms (SNPs) were identified. This has led to the hypothesis that differential gene expression due to SNPs might explain the differences between the human and bovine tubercle bacilli. One phenotypic distinction between M. tuberculosis and M. bovis is nitrate reduction, which not only is an essential diagnostic tool but also contributes to mycobacterial pathogenesis. We previously showed that narGHJI encodes a nitrate reductase in both M. tuberculosis and M. bovis and that NarGHJI-mediated nitrate reductase activity was substantially higher in the human tubercle bacillus. In the present study we used a genetic approach to demonstrate that an SNP within the promoter of the nitrate reductase gene cluster narGHJI is responsible for the different nitrate reductase activity of M. tuberculosis and M. bovis. This is the first example of an SNP that leads to differential gene expression between the human and bovine tubercle bacilli. PMID:15090527

  10. A promoter mutation causes differential nitrate reductase activity of Mycobacterium tuberculosis and Mycobacterium bovis.

    PubMed

    Stermann, Marion; Sedlacek, Ludwig; Maass, Silvia; Bange, Franz-Christoph

    2004-05-01

    The recent publication of the genome sequence of Mycobacterium bovis showed >99.95% identity to M. tuberculosis. No genes unique to M. bovis were found. Instead numerous single-nucleotide polymorphisms (SNPs) were identified. This has led to the hypothesis that differential gene expression due to SNPs might explain the differences between the human and bovine tubercle bacilli. One phenotypic distinction between M. tuberculosis and M. bovis is nitrate reduction, which not only is an essential diagnostic tool but also contributes to mycobacterial pathogenesis. We previously showed that narGHJI encodes a nitrate reductase in both M. tuberculosis and M. bovis and that NarGHJI-mediated nitrate reductase activity was substantially higher in the human tubercle bacillus. In the present study we used a genetic approach to demonstrate that an SNP within the promoter of the nitrate reductase gene cluster narGHJI is responsible for the different nitrate reductase activity of M. tuberculosis and M. bovis. This is the first example of an SNP that leads to differential gene expression between the human and bovine tubercle bacilli. PMID:15090527

  11. Amniotic fluid homocysteine levels, 5,10-methylenetetrahydrafolate reductase genotypes, and neural tube closure sites.

    PubMed

    Wenstrom, K D; Johanning, G L; Owen, J; Johnston, K E; Acton, S; Cliver, S; Tamura, T

    2000-01-01

    A specific gene mutation leading to altered homocysteine metabolism has been identified in parents and fetuses with neural tube defects (NTDs). In addition, current animal and human data indicate that spine closure occurs simultaneously in five separate sites that then fuse. We sought to determine whether either this mutation or abnormal amniotic fluid homocysteine levels are associated with all five neural tube closure sites. We retrieved stored amniotic fluid from cases of isolated fetal neural tube defect diagnosed from 1988 to 1998 (n = 80) and from normal controls matched for race, month and year of amniocentesis, and maternal age. Cases were categorized according to defect site by using all available medical records. The presence or absence of the 677C-->T mutation of 5, 10-methylenetetrahydrafolate reductase (MTHFR) gene was determined, and homocysteine levels were measured; case and controls were compared. Significantly more cases than controls were heterozygous or homozygous for the 677C-->T MTHFR mutation (44% vs. 17%, P < or = 0. 001). Likewise, cases were significantly more likely than controls to have amniotic fluid homocysteine levels >90th centile (>1.85 micromol/L), 27% vs. 10%, P = 0.02. Most (83%) of control cases had both normal MTHFR alleles and normal amniotic fluid homocysteine levels (normal/normal), whereas only 56% of NTD case were normal/normal (P = 0.001). When evaluated by defect site, only defects involving the cervical-lumbar spine, lumbosacral spine, and occipital encephalocele were significantly less likely to be normal/normal than controls (P = 0.007, 0.0003, and 0.007, respectively), suggesting a strong association with the 677C-->T allele. In contrast, anencephaly, exencephaly, and defects confined to the sacrum included many cases that had both normal MTHFR alleles and normal homocysteine and were not significantly different from controls. The 677C-->T MTHFR mutation and elevated homocysteine levels appear to be disproportionately associated with defects spanning the cervical-lumbar spine, lumbosacral spine, and occipital encephalocele. In contrast, anencephaly, exencephaly, and defects confined to the sacrum may not be related to altered homocysteine metabolism. PMID:10602110

  12. The methylenetetrahydrofolate reductase gene variant C677T influences susceptibility to migraine with aura

    Microsoft Academic Search

    Rod A Lea; Micky Ovcaric; James Sundholm; John MacMillan; Lyn R Griffiths

    2004-01-01

    BACKGROUND: The C677T variant in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with increased levels of circulating homocysteine and is a mild risk factor for vascular disease. Migraine, with and without aura (MA and MO), is a prevalent and complex neurovascular disorder that may also be affected by genetically influenced hyperhomocysteinaemia. To determine whether the C677T variant in the MTHFR

  13. 5,10 Methylenetetrahydrofolate reductase genetic polymorphism as a risk factor for neural tube defects

    SciTech Connect

    Ou, C.Y.; Brown, V.K.; Khoury, M.J. [Centers for Disease Control and Prevention, Atlanta, GA (United States)] [and others] [Centers for Disease Control and Prevention, Atlanta, GA (United States); and others

    1996-06-28

    Persons with a thermolabile form of the enzyme 5,10 methylenetetrahydrofolate reductase (MTHFR) have reduced enzyme activity and increased plasma homocysteine which can be lowered by supplemental folic acid. Thermolability of the enzyme has recently been shown to be caused by a common mutation (677C{sup {r_arrow}}T) in the MTHFR gene. We studied 41 fibroblast cultures from NTD-affected fetuses and compared their genotypes with those of 109 blood specimens from individuals in the general population. 677C{sup {r_arrow}}T homozygosity was associated with a 7.2 fold increased risk for NTDs (95% confidence interval: 1.8-30.3; p value: 0.001). These preliminary data suggest that the 677C{sup {r_arrow}}T polymorphism of the MTHFR gene is a risk factor for spina bifida and anencephaly that may provide a partial biologic explanation for why folic acid prevents these types of NTD. 13 refs., 1 fig., 1 tab.

  14. Role of folate status and methylenetetrahydrofolate reductase genotype on the toxicity and outcome of induction chemotherapy in children with acute lymphoblastic leukemia.

    PubMed

    Roy Moulik, Nirmalya; Kumar, Archana; Agrawal, Suraksha; Awasthi, Shally; Mahdi, Abbas Ali; Kumar, Ashutosh

    2015-05-01

    The effect of serum folate levels and methylenetetrahydrofolate reductase (MTHFR) genotype on complications and outcome of induction chemotherapy in 150 children with acute lymphoblastic leukemia (ALL) was studied. Folate deficiency in 26% at baseline was more common in children with MTHFR 677 mutations. Folate deficient children had a higher incidence of neutropenia (p = 0.03), thrombocytopenia (p = 0.02) and febrile neutropenia (p = 0.01) and higher transfusion requirement during induction compared to folate sufficient children. Sepsis related induction deaths were more frequent in folate deficient children (p = 0.02) during induction. Children with 677 and 1298 mutations had a higher incidence of cytopenias (p = 0.01) and mucositis (p = 0.007), the risks of which increased with concomitant folate deficiency. A significant fall in folate levels was observed post-induction (p = 0.02), most markedly in mutant 677 genotypes. Multivariate analysis revealed associations of baseline folate deficiency with low counts at day 14 (p = 0.001) and MTHFR 1298 mutations with mucositis (p = 0.02). PMID:25065700

  15. Mutational reconstructed ferric chelate reductase confers enhanced tolerance in rice to iron deficiency in calcareous soil

    PubMed Central

    Ishimaru, Yasuhiro; Kim, Suyeon; Tsukamoto, Takashi; Oki, Hiroyuki; Kobayashi, Takanori; Watanabe, Satoshi; Matsuhashi, Shinpei; Takahashi, Michiko; Nakanishi, Hiromi; Mori, Satoshi; Nishizawa, Naoko K.

    2007-01-01

    Iron (Fe) deficiency is a worldwide agricultural problem on calcareous soils with low-Fe availability due to high soil pH. Rice plants use a well documented phytosiderophore-based system (Strategy II) to take up Fe from the soil and also possess a direct Fe2+ transport system. Rice plants are extremely susceptible to low-Fe supply, however, because of low phytosiderophore secretion and low Fe3+ reduction activity. A yeast Fe3+ chelate-reductase gene refre1/372, selected for better performance at high pH, was fused to the promoter of the Fe-regulated transporter, OsIRT1, and introduced into rice plants. The transgene was expressed in response to a low-Fe nutritional status in roots of transformants. Transgenic rice plants expressing the refre1/372 gene showed higher Fe3+ chelate-reductase activity and a higher Fe-uptake rate than vector controls under Fe-deficient conditions. Consequently, transgenic rice plants exhibited an enhanced tolerance to low-Fe availability and 7.9× the grain yield of nontransformed plants in calcareous soils. This report shows that enhancing the Fe3+ chelate-reductase activity of rice plants that normally have low endogenous levels confers resistance to Fe deficiency. PMID:17449639

  16. Natural mutations lead to enhanced proteasomal degradation of human Ncb5or, a novel flavoheme reductase.

    PubMed

    Kálmán, Fanni S; Lizák, Beáta; Nagy, Szilvia K; Mészáros, Tamás; Zámbó, Veronika; Mandl, József; Csala, Miklós; Kereszturi, Eva

    2013-07-01

    NADH cytochrome b5 oxidoreductase (Ncb5or) protects ?-cells against oxidative stress and lipotoxicity. The predominant phenotype of lean Ncb5or-null mouse is insulin-dependent diabetes due to ?-cell death. This suggests the putative role of NCB5OR polymorphism in human diabetes. Therefore, we aimed to investigate the effect of natural missense mutations on the expression of human NCB5OR. Protein and mRNA levels of five non-synonymous coding variants were analyzed in transfected HEK293 and HepG2 cells. Although the mRNA levels were only slightly affected by the mutations, the amount of Ncb5or protein was largely reduced upon two Glu to Gly replacements in the third exon (p.E87G, p.E93G). These two mutations remarkably and synergistically shortened the half-life of Ncb5or and their effect could be attenuated by proteasome inhibitors. Our results strongly indicate that p.E87G, p.E93G mutations lead to enhanced proteasomal degradation due to manifest conformational alterations in the b5 domain. These data provide first evidence for natural mutations in NCB5OR gene resulting in decreased protein levels and hence having potential implications in human pathology. PMID:23523930

  17. Associations of MTHFR C677T and MTRR A66G gene polymorphisms with metabolic syndrome: a case-control study in Northern China.

    PubMed

    Yang, Boyi; Fan, Shujun; Zhi, Xueyuan; Wang, Da; Li, Yongfang; Wang, Yinuo; Wang, Yanxun; Wei, Jian; Zheng, Quanmei; Sun, Guifan

    2014-01-01

    Prior evidence indicates that homocysteine plays a role in the development of metabolic syndrome (MetS). Methylenetetrahydrofolate reductase (MTHFR) C677T and methionine synthase reductase (MTRR) A66G polymorphisms are common genetic determinants of homocysteine levels. To investigate the associations of the MTHFR C677T and MTRR A66G polymorphisms with MetS, 692 Chinese Han subjects with MetS and 878 controls were recruited. The component traits of MetS and the MTHFR C677T and MTRR A66G genotypes were determined. A significant association was observed between the MTHFR 677T allele and increased risk of MetS, high fasting blood glucose, high waist circumference, and increasing number of MetS components. The MTRR A66G polymorphism was associated with an increased risk of MetS when combined with the MTHFR 677TT genotype, although there was no association found between MetS and MTRR A66G alone. Furthermore, the MTRR 66GG genotype was associated with high fasting blood glucose and triglycerides. Our data suggest that the MTHFR 677T allele may contribute to an increased risk of MetS in the northern Chinese Han population. The MTRR A66G polymorphism is not associated with MetS. However, it may exacerbate the effect of the MTHFR C677T variant alone. Further large prospective population-based studies are required to confirm our findings. PMID:25429430

  18. Association of Polymorphisms in BDNF, MTHFR, and Genes Involved in the Dopaminergic Pathway with Memory in a Healthy Chinese Population

    ERIC Educational Resources Information Center

    Yeh, Ting-Kuang; Hu, Chung-Yi; Yeh, Ting-Chi; Lin, Pei-Jung; Wu, Chung-Hsin; Lee, Po-Lei; Chang, Chun-Yen

    2012-01-01

    The contribution of genetic factors to the memory is widely acknowledged. Research suggests that these factors include genes involved in the dopaminergic pathway, as well as the genes for brain-derived neurotrophic factor (BDNF) and methylenetetrahydrofolate reductase (MTHFR). The activity of the products of these genes is affected by single…

  19. Prevalence of MTHFR C677T Polymorphism in North Indian Mothers Having Babies with Trisomy 21 Down Syndrome

    ERIC Educational Resources Information Center

    Kohli, Utkarsh; Arora, Sadhna; Kabra, Madhulika; Ramakrishnan, Lakshmy; Gulati, Sheffali; Pandey, Ravindra

    2008-01-01

    Recent studies have evaluated possible links between polymorphisms in maternal folate metabolism genes and Down syndrome. Some of these studies show a significantly increased prevalence of the C677T polymorphism of the 5,10-methylene tetrahydrofolate reductase (NADPH) gene (MTHFR) among mothers who have had babies with Down syndrome. This study…

  20. Targeted Mutations of Bacillus anthracis Dihydrofolate Reductase Condense Complex Structure-Activity Relationships

    SciTech Connect

    J Beierlein; N Karri; A Anderson

    2011-12-31

    Several antifolates, including trimethoprim (TMP) and a series of propargyl-linked analogues, bind dihydrofolate reductase from Bacillus anthracis (BaDHFR) with lower affinity than is typical in other bacterial species. To guide lead optimization for BaDHFR, we explored a new approach to determine structure-activity relationships whereby the enzyme is altered and the analogues remain constant, essentially reversing the standard experimental design. Active site mutants of the enzyme, Ba(F96I)DHFR and Ba(Y102F)DHFR, were created and evaluated with enzyme inhibition assays and crystal structures. The affinities of the antifolates increase up to 60-fold with the Y102F mutant, suggesting that interactions with Tyr 102 are critical for affinity. Crystal structures of the enzymes bound to TMP and propargyl-linked inhibitors reveal the basis of TMP resistance and illuminate the influence of Tyr 102 on the lipophilic linker between the pyrimidine and aryl rings. Two new inhibitors test and validate these conclusions and show the value of the technique for providing new directions during lead optimization.

  1. A New Strategy to Produce a Defensin: Stable Production of Mutated NP-1 in Nitrate Reductase-Deficient Chlorella ellipsoidea

    PubMed Central

    Chen, Yu-Hong; Niu, Li-Li; Sun, Yong-Ru; Zhao, Shi-Min; Yang, Fu-Quan; Wang, Richard R.-C.; Wu, Qing; Zhang, Xiang-Qi; Hu, Zan-Min

    2013-01-01

    Defensins are small cationic peptides that could be used as the potential substitute for antibiotics. However, there is no efficient method for producing defensins. In this study, we developed a new strategy to produce defensin in nitrate reductase (NR)-deficient C. ellipsoidea (nrm-4). We constructed a plant expression vector carrying mutated NP-1 gene (mNP-1), a mature ?-defensin NP-1 gene from rabbit with an additional initiator codon in the 5?-terminus, in which the selection markers were NptII and NR genes. We transferred mNP-1 into nrm-4 using electroporation and obtained many transgenic lines with high efficiency under selection chemicals G418 and NaNO3. The mNP-1 was characterized using N-terminal sequencing after being isolated from transgenic lines. Excitingly, mNP-1 was produced at high levels (approximately 11.42 mg/l) even after 15 generations of continuous fermentation. In addition, mNP-1 had strong activity against Escherichia coli at 5 µg/ml. This research developed a new method for producing defensins using genetic engineering. PMID:23383016

  2. Variants in MTHFR gene and neural tube defects susceptibility in China.

    PubMed

    Wang, Yongxin; Liu, Yuan; Ji, Wenyu; Qin, Hu; Wu, Hao; Xu, Danshu; Turtuohut, Tukebai; Wang, Zengliang

    2015-08-01

    Neural tube defect (NTD) is a severe congenital birth abnormalities involving incomplete neural tube closure. 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene plays key role in folate cycle and methylation cycle, which could affect the DNA synthesis, repair and methylation. In this study, we aim to investigate the correlation between MTHFR polymorphisms and NTD-affected pregnancy. There were 444 participants involved in our study. Tag-SNPs were identified in HapMap Databases. Blood samples were collected from all subjects to further extract the genomic DNAs by TaqMan Blood DNA kits. We also carried out a meta-analysis based on previous published studies to further examine the association between MTHFR polymorphisms and NTD. In case-control study analysis, two SNPs were identified to be associated with NTD risk. The 677 C > T genetic variant was correlated with increased risk of NTD-affected pregnancy. However, the 1298 A > C polymorphism was shown to lower the risk of NTD-affected pregnancy. The protective role of 1298 A > C polymorphisms was further supported by the result of meta-analysis. Our study revealed that the SNPs of 677C > T and 1298A > C in MTHFR were associated with NTD-affected pregnancy, in which 677C > T was a risk factor and in contrast 1298A > C was protective factor against NTD. Our results of meta-analysis also revealed the 1298A > C MTHFR polymorphism play protective role in NTD. PMID:25855017

  3. Association between MTHFR gene polymorphism and NTDs in Chinese Han population

    PubMed Central

    Yu, Yang; Wang, Fang; Bao, Yihua; Lu, Xiaolin; Quan, Li; Lu, Ping

    2014-01-01

    Objective: This study aims to investigate the single nucleotide polymorphisms (SNPs) of 5,10-methylenetetrahydrofolate reductase (MTHFR) gene and neural tube defects (NTDs) in Chinese population. Method: A total of 271 NTDs cases and 192 healthy controls were used in this study. Fifty-two selected single nucleotide polymorphism (SNP) sites in the MTHFR gene were analyzed with next-generation sequencing method. A series of statistical methods were carried out to investigate the correlation between the SNPs and the patient susceptibility to NTDs. Results: Statistical analysis showed a significant correlation between the SNP sites rs1801133 in MTHFR gene and NTDs. The GG genotype, G allele of rs1801133 in MTHFR significantly decreased the incidence of NTDs (OR = 0.449, 95% CI: 0.255-0.789 with genotype, and OR = 0.669, 95% CI: 0.508-0.881 with allele). Conclusions: The gene polymorphism loci rs1801133 in MTHFR gene maybe potential risk factors for NTD in Chinese population. PMID:25356156

  4. Frequency of APOE, MTHFR and ACE polymorphisms in the Zambian population

    PubMed Central

    2014-01-01

    Background Polymorphisms within the apolipoprotein-E (APOE), Methylenetetrahydrofolate reductase (MTHFR) and Angiotensin I-converting enzyme (ACE) genes has been associated with cardiovascular and cerebrovascular disorders, Alzheimer’s disease and other complex diseases in various populations. The aim of the study was to analyze the allelic and genotypic frequencies of APOE, MTHFR C677T and ACE I/D gene polymorphisms in the Zambian population. Results The allele frequencies of APOE polymorphism in the Zambian populations were 13.8%, 59.5% and 26.7% for the ?2, ?3 and ?4 alleles respectively. MTHFR C677T and ACE I/D allele frequencies were 8.6% and 13.8% for the T and D minor alleles respectively. The ?2?2 genotype and TT genotype were absent in the Zambian population. The genetic distances between Zambian and other African and non-African major populations revealed an independent variability of these polymorphisms. Conclusion We found that the APOE ?3 allele and the I allele of the ACE were significantly high in our study population while there were low frequencies observed for the MTHFR 677 T and ACE D alleles. Our analysis of the APOE, MTHFR and ACE polymorphisms may provide valuable insight into the understanding of the disease risk in the Zambian population. PMID:24679048

  5. Structural and mutational studies of the carboxylate cluster in iron-free ribonucleotide reductase R2.

    PubMed

    Andersson, Martin E; Högbom, Martin; Rinaldo-Matthis, Agnes; Blodig, Wolfgang; Liang, Yuhe; Persson, Bert-Ove; Sjöberg, Britt-Marie; Su, Xiao-Dong; Nordlund, Pär

    2004-06-22

    The R2 protein of ribonucleotide reductase features a di-iron site deeply buried in the protein interior. The apo form of the R2 protein has an unusual clustering of carboxylate side chains at the empty metal-binding site. In a previous study, it was found that the loss of the four positive charge equivalents of the diferrous site in the apo protein appeared to be compensated for by the protonation of two histidine and two carboxylate side chains. We have studied the consequences of removing and introducing charged residues on the local hydrogen-bonding pattern in the region of the carboxylate cluster of Corynebacterium ammoniagenes and Escherichia coli protein R2 using site-directed mutagenesis and X-ray crystallography. The structures of the metal-free forms of wild-type C. ammoniagenes R2 and the mutant E. coli proteins D84N, S114D, E115A, H118A, and E238A have been determined and their hydrogen bonding and protonation states have been structurally assigned as far as possible. Significant alterations to the hydrogen-bonding patterns, protonation states, and hydration is observed for all mutant E. coli apo proteins as compared to wild-type apo R2. Further structural variations are revealed by the wild-type apo C. ammoniagenes R2 structure. The protonation and hydration effects seen in the carboxylate cluster appear to be due to two major factors: conservation of the overall charge of the site and the requirement of electrostatic shielding of clustered carboxylate residues. Very short hydrogen-bonding distances between some protonated carboxylate pairs are indicative of low-barrier hydrogen bonding. PMID:15196041

  6. Polymorphisms of methylenetetrahydrofolate reductase and methionine synthase genes and bladder cancer risk: a case–control study with meta-analysis

    Microsoft Academic Search

    Meilin Wang; Haixia Zhu; Guangbo Fu; Miaomiao Wang; Zhizhong Zhang; Qiang Lu; Shizhi Wang; Zhengdong Zhang

    2009-01-01

    Folate deficiency due to the methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MS) variants leads to carcinogenesis\\u000a by affecting DNA synthesis, repair, and methylation. We hypothesized that the MTHFR C677T, A1298C, and MS A2756G polymorphisms are associated with risk of bladder cancer. In a case–control study of 239 bladder cancer cases and\\u000a 250 cancer-free controls, we found that the MTHFR 677TT

  7. MTHFR association with arteriosclerotic vascular disease?

    Microsoft Academic Search

    Olivia Fletcher; Anna M. Kessling

    1998-01-01

    Complex diseases are far more common than diseases that follow simple Mendelian patterns of inheritance. Difficulties are\\u000a experienced in the designing of experiments to dissect out the contribution of a single allele to a complex phenotype. We\\u000a review the literature regarding a point mutation in methylenetetrahydrofolate reductase, a candidate gene for susceptibility\\u000a to vascular diseases.

  8. One-Carbon Metabolism, MTHFR Polymorphisms, and Risk of Breast Cancer

    Microsoft Academic Search

    Jia Chen; Marilie D. Gammon; Wendy Chan; Caroline Palomeque; James G. Wetmur; Geoffrey C. Kabat; Susan L. Teitelbaum; Julie A. Britton; Mary Beth Terry; Alfred I. Neugut; Regina M. Santella

    2005-01-01

    Accumulating evidence from epidemiologic studies suggests that risk of breast cancer is reduced in relation to increased consumption of folate and related B vitamins. We investigated independent and joint effects of B vitamin intake as well as two polymorphisms of a key one-carbon metabolizing gene (i.e., methylenetetrahydrofolate reductase (MTHFR) 677C>T and 1298A>C) on breast cancer risk. The study uses the

  9. Urinary Tract Anomalies Associated with MTHFR Gene Polymorphism C677T in Girls

    Microsoft Academic Search

    Jana Behunova; Lucia Klimcakova; Ludmila Podracka

    2011-01-01

    Background\\/Aims: Periconceptional folate has a preventive effect not only on neural tube defects, but possibly also on other birth defects such as urinary tract anomalies (UTA), orofacial clefts and conotruncal heart defects. Folate metabolism gene variants are therefore being investigated as potential susceptibility factors. Methods: We assessed the methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C genotypes in 132 UTA patients

  10. Try235Phe homozygous mutation of the steroid 5-a reductase type 2 (SRD5A2) gene in a Turkish patient.

    PubMed

    Parlak, Mesut; Durmaz, Erdem; Gursoy, Semin; Bircan, Iffet; Akcurin, Sema

    2014-01-01

    Steroid 5-a reductase type 2 isoenzyme (SRD5A2) deficiency is a male-limited autosomal recessive disorder that results in decreased conversion of testosterone to dihydrotestosterone with various de.gree of incomplete virilization in affected 46, XY infants. No clear genotype-phenotype relationship has been reported till date; moreover, the same mutation can result in considerable heterogeneity in clinical manifestations. Of 6 documented cases with Try235Phe homozygous mutation of the SRD5A2 gene, 3 patients had predominantly female external genitalia whereas the other 3 had predominantly male phenotype. We report Try235Phe homozygous mutation of the SRD5A2 gene in a Turkish patient who was initially assigned as a girl because of the predominantly female appearance of the external genitalia. PMID:25266188

  11. Association of methylenetetrahydrofolate reductase C677T polymorphism and serum lipid levels in the Guangxi Bai Ku Yao and Han populations

    Microsoft Academic Search

    Lin Zhang; Rui-Xing Yin; Wan-Ying Liu; Lin Miao; Dong-Feng Wu; Lynn Htet Htet Aung; Xi-Jiang Hu; Xiao-Li Cao; Jin-Zhen Wu; Shang-Ling Pan

    2010-01-01

    BACKGROUND: The association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and serum lipid profiles is still controversial in diverse ethnics. Bai Ku Yao is an isolated subgroup of the Yao minority in China. The aim of the present study was to eveluate the association of MTHFR C677T polymorphism and several environmental factors with serum lipid levels in the Guangxi Bai Ku

  12. Association between MTHFR 677C/T polymorphism and psoriasis risk: a meta-analysis.

    PubMed

    Qi, J H; Qi, J H; Shi, N; Chen, Y J; Nie, G

    2015-01-01

    Previous studies investigating the association between methylenetetrahydrofolate reductase (MTHFR) 677C/T polymorphisms and psoriasis risk have reported inconsistent results. The present meta-analysis aimed to comprehensively evaluate the association between MTHFR 677C/T polymorphism and psoriasis risk. The studies regarding the association between MTHFR 677C/T polymorphism and psoriasis risk were retrieved from the PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure, and Chinese Biomedical databases. Data were extracted and statistical analysis was performed with the program STATA 12.0. A total of seven studies involving 1290 psoriasis cases and 1068 healthy controls were retrieved. Combined analysis showed that there was no significant difference in MTHFR 677C/T genotype distribution between psoriasis and control subjects in the comparisons C vs T, CC vs CT + TT, CC + CT vs TT, CC vs TT, and CC vs CT [respectively: odds ratio (OR) = 0.98, 95% confidence interval (CI) = 0.76-1.26, P = 0.882; OR = 1.11, 95%CI = 0.81-1.51, P = 0.526; OR = 0.79, 95%CI = 0.53-1.19, P = 0.261; OR = 0.88, 95%CI = 0.51-1.52, P = 0.648; OR = 1.19, 95%CI = 0.90-1.58, P = 0.217]. Subgroup analysis by ethnicity also showed no significant association between MTHFR 677C/T polymorphism and psoriasis risk in both Asian and Caucasian populations. In conclusion, this meta-analysis indicates that MTHFR 677C/T polymorphism may not be associated with psoriasis risk. PMID:25966157

  13. Interaction between the MTHFR C677T polymorphism and traumatic childhood events predicts depression

    PubMed Central

    Lok, A; Bockting, C L H; Koeter, M W J; Snieder, H; Assies, J; Mocking, R J T; Vinkers, C H; Kahn, R S; Boks, M P; Schene, A H

    2013-01-01

    Childhood trauma is associated with the onset and recurrence of major depressive disorder (MDD). The thermolabile T variant of the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism (rs1801133) is associated with a limited (oxidative) stress defense. Therefore, C677T MTHFR could be a potential predictor for depressive symptomatology and MDD recurrence in the context of traumatic stress during early life. We investigated the interaction between the C677T MTHFR variant and exposure to traumatic childhood events (TCEs) on MDD recurrence during a 5.5-year follow-up in a discovery sample of 124 patients with recurrent MDD and, in an independent replication sample, on depressive symptomatology in 665 healthy individuals from the general population. In the discovery sample, Cox regression analysis revealed a significant interaction between MTHFR genotype and TCEs on MDD recurrence (P=0.017). Over the 5.5-year follow-up period, median time to recurrence was 191 days for T-allele carrying patients who experienced TCEs (T+ and TCE+); 461 days for T? and TCE+ patients; 773 days for T+ and TCE? patients and 866 days for T? and TCE? patients. In the replication sample, a significant interaction was present between the MTHFR genotype and TCEs on depressive symptomatology (P=0.002). Our results show that the effects of TCEs on the prospectively assessed recurrence of MDD and self-reported depressive symptoms in the general population depend on the MTHFR genotype. In conclusion, T-allele carriers may be at an increased risk for depressive symptoms or MDD recurrence after exposure to childhood trauma. PMID:23900311

  14. A prospective study of methylenetetrahydrofolate reductase and methionine synthase gene polymorphisms, and risk of colorectal adenoma

    Microsoft Academic Search

    Jia Chen; Edward Giovannucci; Susan E. Hankinson; Jing Ma; Walter C. Willett; Donna Spiegelman; Karl T. Kelsey; David J. Hunter

    1998-01-01

    We examined the relationship between a functional poly- morphism (667C?T, ala?val) of the methylenetetrahy- drofolate reductase gene (MTHFR) and the risk of colorectal adenomas in the prospective Nurses' Health Study. Among 257 incident polyp cases and 713 controls, the MTHFR val\\/val polymorphism (relative risk (RR) J 1.35, 95% confidence interval (CI) 0.84-2.17) was not significantly associated with risk of adenomas.

  15. Methylenetetrahydrofolate reductase and methionine synthase polymorphisms and risk of bladder cancer in a Tunisian population

    Microsoft Academic Search

    Slah Ouerhani; Elisabete Oliveira; Raja Marrakchi; Mohamed R. Ben Slama; Mohamed Sfaxi; Mohsen Ayed; Mohamed Chebil; António Amorim; Amel Benammar El Gaaied; Maria João Prata

    2007-01-01

    Folate insufficiency can induce carcinogenesis by decreasing DNA methylation. It is well known that DNA hypomethylation is a common feature in a number of cancers. Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MS) are enzymes that play central roles in the folate metabolic pathway. Two common polymorphisms in the MTHFR gene (C677T and A1298C) and one in the MS gene (A2756G)

  16. 5,10-Methylenetetrahydrofolate Reductase Gene Variants and Congenital Anomalies: A HuGE Review

    Microsoft Academic Search

    Lorenzo D. Botto; Quanhe Yang

    2000-01-01

    The enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR) is involved in folate metabolism. The MTHFR gene is located on chromosome 1 (1p36.3), and two common alleles, the C677T (thermolabile) allele and the A1298C allele, have been described. The population frequency of C677T homozygosity ranges from 1% or less among Blacks from Africa and the United States to 20% or more among Italians and

  17. Prevalence of MTHFR C677T and MS A2756G polymorphisms in major depressive disorder, and their impact on response to fluoxetine treatment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To examine the prevalence of the C677T polymorphism of the methylene tetrahydrofolate reductase (MTHFR) gene and the A2756G polymorphism of methionine synthase (MS), and their impact on antidepressant response. We screened 224 subjects (52% female, mean age 39 +/- 11 years) with SCID-diagnosed major...

  18. Evaluation of MTHFR677C>T Polymorphism in Prediction and Prognosis of Esophageal Squamous Cell Carcinoma: A Case-Control Study in a Northern Indian Population

    Microsoft Academic Search

    Meenakshi Umar; Rohit Upadhyay; Rohini Khurana; Shaleen Kumar; Uday Chand Ghoshal; Balraj Mittal

    2010-01-01

    Early diagnosis and better prognosis of esophageal squamous cell carcinoma (ESCC) is still a challenge. Besides environmental risk factors, nutritional deficiencies have an established role in pathogenesis of ESCC. Folate deficiency and functional polymorphisms in folate metabolizing genes such as methylene tetrahydrofolate reductase (MTHFR) 677C>T may have oncogenic role through disruption of normal DNA methylation pattern, synthesis, and impaired DNA

  19. Polymorphisms in the MTHFR gene are associated with breast cancer risk and prognosis in a Chinese population.

    PubMed

    Lu, Qing; Jiang, Ke; Li, Qiong; Ji, Ya-Jie; Chen, Wei-Li; Xue, Xiao-Hong

    2015-05-01

    Breast cancer is the most common cancer affecting women in China and the world. Folate supplementation is proven to be effective in reducing the risk of breast cancer or improving its prognosis. Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme involved in folate metabolism and DNA synthesis. This study aims to examine whether single nucleotide polymorphisms (SNP) in the MTHFR gene are associated with risk and survival of breast cancer and serum folate levels in healthy controls. We genotyped nine tagging SNPs in the MTHFR gene in a case-control study, including 560 breast cancer cases and 560 healthy controls in China. We found that TT genotype of rs1801133 had significant increased risk of breast cancer [adjusted odds ratio (OR)?=?1.60, 95 % confidence interval (CI) 1.12-2.28] compared with CC genotype, and CC genotype of rs9651118 conferred significant reduced risk of breast cancer (adjusted OR?=?0.65, 95 % CI 0.45-0.95) compared to TT genotype. Haplotype analysis also showed that MTHFR CACCAA and AGTCAC haplotypes (rs12121543-rs13306553-rs9651118-rs1801133-rs4846048-rs1801131) had significant reduced risk of breast cancer (adjusted OR?=?0.70, 95 % CI 0.58-0.86; adjusted OR?=?0.57, 95 % CI 0.40-0.80) compared with CATTAA haplotype. Besides, MTHFR rs9651118 CC genotype was significantly associated with survival in breast cancer cases (adjusted hazard ratio (HR)?=?0.63, 95 % CI 0.40-0.99). But none of the SNPs in the MTHFR gene was associated with serum folate level in healthy controls. These findings suggest that variants in the MTHFR gene may influence the risk and prognosis of breast cancer. PMID:25566964

  20. Enrichment of MTHFR 677?T in a Chinese long-lived cohort and its association with lipid modulation

    PubMed Central

    2014-01-01

    Background Variants in the Methylenetetrahydrofolate reductase (MTHFR) gene may result in a lowered catalytic activity and associate with subsequent elevated serum homocysteine (Hcy) concentration, abnormal DNA synthesis and methylation, cardiovascular risk, and unhealthy aging. Several investigations on the relationship of MTHFR C677T polymorphism with serum lipid profile and longevity have been conducted in some populations, but the findings remain mixed. Herein, we sought to look at the association between MTHFR C677T and lipid profile in a longevous cohort in Bama, a well-known home of longevity in China. Methods Genotyping of MTHFR C677T was undertaken in 516 long-lived inhabitants (aged 90 and older, long-lived group, LG) and 493 healthy controls (aged 60–75, non-long-lived group, non-LG) recruited from Bama area. Correlation between MTHFR genotypes and lipids was then evaluated. Results T allele and TT genotype were significantly more prevalent in LG (P?=?0.001 and 0.002, respectively), especially in females, than in non-LG. No difference in the tested lipid measures among MTHFR C677T genotypes was observed in LG, non-LG and total population (P?>?0.05 for all). However, female but not male T carriers exhibited higher TC and LDL-C levels than did T noncarriers in the total population and in LG after stratification by sex (P?MTHFR 677?T genotypes and its modest unfavorable impact on lipids in Bama long-lived individuals may imply an existence of other protective genotypes which require further determination. PMID:24968810

  1. MTHFR rs1801133 C>T polymorphism is associated with an increased risk of tetralogy of Fallot

    PubMed Central

    HUANG, JIANBING; MEI, JU; JIANG, LIANYONG; JIANG, ZHAOLEI; LIU, HAO; DING, FANGBAO

    2014-01-01

    Abnormal folate metabolism and common variants of folate-metabolizing enzymes have been described as possible risk factors for congenital heart disease (CHD). Two important folate-metabolizing enzymes involved in the folate/homocysteine metabolic pathway are 5,10-methylenetetrahydrofolate reductase (MTHFR) and methylenetetrahydrofolate dehydrogenase 1 (MTHFD1). MTHFR and MTHFD1 polymorphisms may be associated with CHD susceptibility. To evaluate the impact of MTHFR and MTHFD1 single-nucleotide polymorphisms (SNPs) on CHD susceptibility, we genotyped functional MTHFR SNPs rs1801133 C>T, rs1801131 A>C and rs2274976 G>A, and MTHFD SNPs rs2236225 C>T, rs1950902 G>A and rs1076991 A>G in a hospital-based case-control study of 173 tetralogy of Fallot (TOF) cases and 207 non-CHD controls. When MTHFR rs1801133 CC homozygote genotype was used as the reference group, the TT genotype was associated with a significantly increased risk for TOF [TT vs. CC: odds ratio (OR)=1.67; 95% confidence interval (CI): 1.01–2.75; P=0.046]. In the recessive model, when MTHFR rs1801133 CC/CT genotype was used as the reference group, the TT homozygote genotype was associated with a significantly increased risk for TOF (OR=1.81, 95% CI: 1.15–2.84; P=0.010). In conclusion, our findings suggest that MTHFR rs1801133 C>T polymorphism may play a role in susceptibility for TOF. Large-scale studies with a more rigorous study design including diverse ethnic populations are required to confirm these findings. PMID:24649091

  2. Plasmodium falciparum strains harboring dihydrofolate reductase with the I164L mutation are absent in Malawi and Zambia even under antifolate drug pressure.

    PubMed

    Ochong, Edwin; Bell, David J; Johnson, David J; D'Alessandro, Umberto; Mulenga, Modest; Muangnoicharoen, Sant; Van Geertruyden, Jean-Pierre; Winstanley, Peter A; Bray, Patrick G; Ward, Stephen A; Owen, Andrew

    2008-11-01

    The Plasmodium falciparum dihydrofolate reductase (PfDHFR) enzyme is the target of pyrimethamine, a component of the antimalarial pyrimethamine-sulfadoxine. Resistance to this drug is associated primarily with mutations in the Pfdhfr gene. The I164L mutant allele is of particular interest, because strains possessing this mutation are highly resistant to pyrimethamine and to chlorproguanil, a component of chlorproguanil-dapsone. A recent study from Malawi reported this mutation at a prevalence of 4.7% in parasites from human immunodeficiency virus-positive pregnant women by using a real-time PCR method. These observations have huge implications for the use of pyrimethamine-sulfadoxine, chlorproguanil-dapsone, and future antifolate-artemisinin combinations in Africa. It was imperative that this finding be rigorously tested. We identified a number of critical limitations in the original genotyping strategy. Using a refined and validated real-time PCR strategy, we report here that this mutation was absent in 158 isolates from Malawi and 42 isolates from Zambia collected between 2003 and 2005. PMID:18725445

  3. Status of vitamin B-12 and B-6 but not of folate, homocysteine and the methylenetetrahydrofolate reductase C677T polymorphism are associated with impaired cognition and depression in adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The C677T polymorphism of the methylene tetrahydrofolate reductase (MTHFR) gene differs in frequency in different ethnic groups which have differing prevalence of age-related cognitive impairments. We used a battery of neuropsychological tests to examine association of the MTHFR C677T polymorphism w...

  4. Association of von Willebrand factor activity with ACE I/D and MTHFR C677T polymorphisms in migraine.

    PubMed

    Tietjen, G E; Herial, N A; Utley, C; White, L; Yerga-Woolwine, S; Joe, B

    2009-09-01

    Angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms are linked to endothelial dysfunction and to cerebral white matter lesions. Objectives of this study were to determine if ACE and MTHFR gene polymorphisms are associated with von Willebrand factor (vWF) activity, an endothelial dysfunction marker, and with a distinct headache phenotype. We enrolled 64 women (18-50 years old) with International Classification of Headache Disorders, 2nd edn migraine without aura (MoA) and 61 with aura (MA). Genotypic frequencies: ACE DD 35%, ID 42%, II 23%, and MTHFR TT 17%, CT 40%, CC 43%. Those with ACE DD genotype had higher levels of vWF activity (152%) compared with ID and II genotypes. Levels were highest (179%) with combined ACE DD and MTHFR TT genotypes. ACE DD was associated with higher headache frequency, and MTHFR TT was associated with MA. In migraine, vWF activity may be a marker of endothelial-mediated genetic risk for ischaemic conditions. PMID:19298544

  5. A potential interaction between COMT and MTHFR genetic variants in Han Chinese patients with bipolar II disorder

    PubMed Central

    Wang, Liang-Jen; Lee, Sheng-Yu; Chen, Shiou-Lan; Chang, Yun-Hsuan; Chen, Po See; Huang, San-Yuan; Tzeng, Nian-Sheng; Chen, Kao Chin; Lee, I. Hui; Wang, Tzu-Yun; Yang, Yen Kuang; Lu, Ru-Band

    2015-01-01

    Bipolar II disorder (BP-II), characterized by recurrent dysregulation of mood, is a serious and chronic psychiatric illness. However, BP-II is commonly under-recognized, even in psychiatric settings. Because dopaminergic disturbance is thought to be involved in the development of bipolar disorder (BPD), it seems essential to investigate dopamine-related genes like the catechol-O-methyltransferase (COMT) gene, which are involved in dopamine metabolism, and the methylenetetrahydrofolate reductase (MTHFR) gene, which may affect COMT methylation and COMT function. The current study examined the association and interaction of the COMT Val158Met and MTHFR C677T variants with BP-II. Nine hundred seventy-eight participants were recruited: 531 with BP-II and 447 healthy controls. The genotypes of the COMT and MTHFR polymorphisms were determined using a polymerase chain reaction-restriction fragment length polymorphism analysis. Logistic regression analysis showed a significant interaction effect of the COMT Val158Met Val/Val genotype and the MTHFR C677T C/T + T/T genotype (P = 0.039) for the protective effect on the odds of developing BP-II. Our findings support preliminary evidence that the COMT and MTHFR genes interact in BP-II, and they imply the connection of both dopaminergic pathways and methylation pathways in the pathogenesis of BP-II. PMID:25744938

  6. MTHFR C677T Polymorphism and Risk of Congenital Heart Defects: Evidence from 29 Case-Control and TDT Studies

    PubMed Central

    Gong, Fangqi; Zhu, Weihua; Fu, Songling

    2013-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme for folate metabolism in humans; it is encoded by the MTHFR gene. Several studies have assessed the association between MTHFR C677T polymorphism and the risk of congenital heart defects (CHDs), while the results were inconsistent. Methods and Findings Multiple electronic databases were searched to identify relevant studies published up to July 22, 2012. Data from case-control and TDT studies were integrated in an allelic model using the Catmap and Metafor software. Twenty-nine publications were included in this meta-analysis. The overall meta-analysis showed significant association between MTHFR C677T polymorphism and CHDs risk in children with heterogeneity (Pheterogeneity?=?0.000) and publication bias (Pegger?=?0.039), but it turned into null after the trim-and-fill method was implemented (OR?=?1.12, 95% CI?=?0.95–1.31). Nevertheless, positive results were obtained after stratified by ethnicity and sample size in all subgroups except the mixed population. For mothers, there was significant association between the variant and CHDs without heterogeneity (Pheterogeneity?=?0.150, OR?=?1.16, 95% CI?=?1.05–1.29) and publication bias (Pegger?=?0.981). However, the results varied across each subgroup in the stratified analysis of ethnicity and sample size. Conclusions Both infant and maternal MTHFR C677T polymorphisms may contribute to the risk of CHDs. PMID:23536781

  7. Is the prevalence of MTHFR C677T polymorphism associated with ultraviolet radiation in Eurasia?

    PubMed

    Yafei, Wang; Lijun, Pei; Jinfeng, Wang; Xiaoying, Zheng

    2012-12-01

    The methylenetetrahydrofolic acid reductase (MTHFR) C677T polymorphism causes an amino-acid change from alanine to valine and results in the enzyme becoming thermolabile and half decreased activity. Its prevalence varies among global population. We collected data about MTHFR C677T polymorphism prevalence from epidemiology studies, as well as ultraviolet (UV) radiations and some other climatological factors from the internet. The results of the correlation and quadric regression showed that there was inverse U-shape relationship between T allele frequency and UV radiation. The explanatory power of UV radiation was stronger than latitude and all climatological factors. Our results supported the hypothesis that the distribution pattern of MTFHR C677T polymorphism in Eurasia might be the result of interaction of genetic and environmental natural selection, especially the UV radiation. PMID:22992775

  8. MTHFR 677TT genotype and disease risk: is there a modulating role for B-vitamins?

    PubMed

    Reilly, R; McNulty, H; Pentieva, K; Strain, J J; Ward, M

    2014-02-01

    Methylenetetrahydrofolate reductase (MTHFR) is a critical folate-metabolising enzyme which requires riboflavin as its co-factor. A common polymorphism (677C?T) in the MTHFR gene results in reduced MTHFR activity in vivo which in turn leads to impaired folate metabolism and elevated homocysteine concentrations. Homozygosity for this polymorphism (TT genotype) is associated with an increased risk of a number of conditions including heart disease and stroke, but there is considerable variability in the extent of excess risk in various reports. The present review will explore the evidence which supports a role for this polymorphism as a risk factor for a number of adverse health outcomes, and the potential modulating roles for B-vitamins in alleviating disease risk. The evidence is convincing in the case which links this polymorphism with hypertension and hypertensive disorders of pregnancy, particularly preeclampsia. Furthermore, elevated blood pressure was found to be highly responsive to riboflavin intervention specifically in individuals with the MTHFR 677TT genotype. Future intervention studies targeted at these genetically predisposed individuals are required to further investigate this novel gene-nutrient interaction. This polymorphism has also been associated with an increased risk of neural tube defects (NTD) and other adverse pregnancy outcomes; however, the evidence in this area has been inconsistent. Preliminary evidence has suggested that there may be a much greater need for women with the MTHFR 677TT genotype to adhere to the specific recommendation of commencing folic acid prior to conception for the prevention of NTD, but this requires further investigation. PMID:24131523

  9. Screening of polymorphisms for MTHFR and DHFR genes in spina bifida children and their mothers

    NASA Astrophysics Data System (ADS)

    Husna, M. Z.; Endom, I.; Ibrahim, S.; Selvi, N. Amaramalar; Fakhrurazi, H.; Htwe, R. Ohnmar; Kanehaswari, Y.; Halim, A. R. Abdul; Wong, S. W.; Subashini, K.; Syahira, O. Nur; Aishah, S.

    2013-11-01

    Mechanism underlying the beneficial effect of folic acid supplementation in reducing the risk of neural tube defect is still not well understood. Current evidences show the involvement of folic acid metabolic gene's polymorphism as contributing factors that regulate this pathway. Therefore, the objective of this research was to determine the presence of C677T polymorphism for methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase (DHFR-19 bp deletion) genes between mother-children pairs of case and control. With the approval of UKMMC ethic committee, genomic DNA was extracted from one hundred and forty consented bloods. Polymerase chain reaction (PCR), PCR-RFLP (Restriction Fragment Length Polymorphism) and sequencing were employed to verify each nucleotide change. Our result shows that mutant MTHFR and DHFR alleles are present in all Malaysian sub-ethnic groups, case and control. Even though mutant MTHFR are found to be slightly higher in the case groups, 75% of the affected child is a non carrier for this allele and 62.5% of the mothers with an affected child are genotypically normal. For DHFR, almost all (87.5-100%) investigated samples are a carrier or having a double DHFR deletion be it a case or control pairs. However, strong maternal inheritance shown by the deleted allele might be due to a cascade effect of lacks of folate consumption or maternal uniparental disomy. In conclusion, the use of MTHFR and DHFR as markers in determining the risk of having spina bifida baby is uninformative and plays a small indirect role as the genetic causes of spina bifida. Therefore, spina bifida remains etiologically unknown polygenic and quantitative developmental trait whereby the searches for positive genetic marker need to be continued.

  10. Increased prevalence of combined MTR and MTHFR genotypes among individuals with severely elevated total homocysteine plasma levels

    Microsoft Academic Search

    Alexandra Feix; Robert Fritsche-Polanz; Josef Kletzmayr; Andreas Vychytil; Walter H. Hörl; Gere Sunder-Plassmann; Manuela Födinger

    2001-01-01

    The prevalence of the methionine synthase (MTR) 2756A?G polymorphism among individuals with severely elevated total homocysteine (tHcy) plasma levels is unknown. Therefore, 1,716 subjects, including 415 hemodialysis patients, 179 peritoneal dialysis patients, 733 kidney graft recipients, and 389 healthy subjects, were investigated. The distribution of MTR 2756A?G, as well as 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C?T\\/1298A?C, genotypes among study participants with extremely

  11. Isolation of mutants of Acinetobacter calcoaceticus deficient in wax ester synthesis and complementation of one mutation with a gene encoding a fatty acyl coenzyme A reductase.

    PubMed Central

    Reiser, S; Somerville, C

    1997-01-01

    Acinetobacter calcoaceticus BD413 accumulates wax esters and triacylglycerol under conditions of mineral nutrient limitation. Nitrosoguanidine-induced mutants of strain BD413 were isolated that failed to accumulate wax esters under nitrogen-limited growth conditions. One of the mutants, Wow15 (without wax), accumulated wax when grown in the presence of cis-11-hexadecenal and hexadecanol but not hexadecane or hexadecanoic acid. This suggested that the mutation may have inactivated a gene encoding either an acyl-acyl carrier protein or acyl-coenzyme A (CoA) reductase. The Wow15 mutant was complemented with a cosmid genomic library prepared from wild-type A. calcoaceticus BD413. The complementary region was localized to a single gene (acr1) encoding a protein of 32,468 Da that is 44% identical over a region of 264 amino acids to a product of unknown function encoded by an open reading frame associated with mycolic acid synthesis in Mycobacterium tuberculosis H37Ra. Extracts of Escherichia coli cells expressing the acr1 gene catalyzed the reduction of acyl-CoA to the corresponding fatty aldehyde, indicating that the gene encodes a novel fatty acyl-CoA reductase. PMID:9139916

  12. Methionine synthase A2756G and methylenetetrahydrofolate reductase A1298C polymorphisms are not risk factors for idiopathic venous thromboembolism

    Microsoft Academic Search

    Ophira Salomon; Nurit Rosenberg; Ariella Zivelin; David M Steinberg; Nurit Kornbrot; Rima Dardik; Aida Inbal; Uri Seligsohn

    2001-01-01

    Hyperhomocysteinemia is a defined risk factor for venous thromboembolism (VTE). Several polymorphisms of genes encoding for enzymes acting in the remethylation pathway of homocysteine metabolism, ie, methionine synthase (MS) A2756G, methylenetetrahydrofolate reductase (MTHFR) C677T and MTHFR A1298C, can cause increased homocysteine levels particularly in patients with deficiencies of folic acid, vitamin B6, or B12 and hence be potential risk factors

  13. Association of MTHFR C677T polymorphism with schizophrenia and its effect on episodic memory and gray matter density in patients

    PubMed Central

    Zhang, Yanling; Yan, Hao; Tian, Lin; Wang, Fang; Lu, Tianlan; Wang, Lifang; Yan, Jun; Liu, Qi; Kang, Lan; Ruan, Yanyan; Zhang, Dai; Yue, Weihua

    2013-01-01

    Growing evidence suggests that the methylenetetrahydrofolate reductase (MTHFR) may play a role in the pathogenesis of schizophrenia. Recent studies suggested that the MTHFR 677T, as a risk allele, has an impact on brain activation and memory function in schizophrenia patients. To confirm further the association between this functional polymorphism and schizophrenia, we detected genotypes of MTHFR C677T polymorphism in 1,002 schizophrenic patients and 1,036 controls of Chinese Han population, by using direct DNA sequencing method. To explore further effects of MTHFR C677T polymorphism on memory and brain function in schizophrenia, 33 schizophrenia patients and 29 healthy participants were selected from above samples to be assessed with MRI scanning and episodic memory (EM) examination. The case - control association study results showed that the MTHFR C677T was associated with schizophrenia (?2 = 14.11, P = 1.74 × 10?4, OR = 0.79; 95% CI = 0.70 – 0.89). We also found that the MTHFR 677T allele had a load-dependent effect on EM in schizophrenic patients, but not in healthy control participants. Further analysis on gray matter density (GMD) revealed significant diagnostic effects in bilateral frontal cortices, bilateral insula, left medial temporal cortex and bilateral occipital cortices, effects of MTHFR genotype in the right insula, right inferior frontal gyrus, right rolandic opercula, right parahippocampal gyrus and right medial temporal pole, and effects of genotype-diagnosis interaction in the right temporal gyrus. Our findings suggested that the MTHFR 677T allele might have effect on risk of schizophrenia, memory impairment and GMD changes in patients. PMID:23318463

  14. Interaction of MTHFR C677T and A1298C, and MTR A2756G gene polymorphisms in breast cancer risk in a population in Northeast Brazil.

    PubMed

    de Cássia Carvalho Barbosa, Rita; da Costa, Débora Menezes; Cordeiro, Denise Ellen Francelino; Vieira, Ana Patricia Freitas; Rabenhorst, Silvia Helena Barem

    2012-11-01

    Polymorphisms in genes encoding enzymes of folate metabolism are a focus of breast cancer risk studies due of the role of these enzymes in DNA methylation, synthesis, and repair. MTHFR, encoding for 5,10-methylenetetrahydrofolate reductase, is one of the most studied genes in this regard, but findings are controversial, and the majority of studies have analyzed polymorphisms individually. In this case control study, we examined the combination of the polymorphisms MTHFR C677T and A1298C with MTR A2756G, where MTR, methionine synthase, is an important enzyme of the folate cycle in the methylation pathway. One hundred and forty-two patients with breast cancer and controls were included and the genotypes were determined using PCR-RFLP. In the population studied, individuals carrying the polymorphic allele in the heterozygous state for both enzymes, MTHFR C677T and MTR A2756G, had an increased risk [odds ratio, OR=2.77 (95% confidence interval, CI=1.19-6.52)] for disease, compared to those with the wild genotype. In addition, individuals carrying the MTR 2756 genotype AG had an increased risk when this was combined with the MTHFR 1298 genotype CC [OR=5.13 (95% CI=0.87-38.82)]. No significant results were found from the analyses associating the MTHFR C677T and A1298C genotypes. However, when stratifying the patients by age (50 years old as the cut-off), patients over 50 years old had greater risk, with the presence of both MTHFR polymorphisms in the heterozygous state [OR=5.33 (95% CI=1.42-21.03)]. This study points out the importance of the interactions between the MTHFR C677T, MTHFR A1298C and MTR A2756G polymorphisms, and also highlights the relevance of the MTR A2756G polymorphism and age in breast cancer risk. PMID:23155246

  15. MTHFR C677T Predisposes to POAG but Not to PACG in a North Indian Population: A Case Control Study

    PubMed Central

    Gupta, Shashank; Bhaskar, Pradeep Kumar; Bhardwaj, Ritu; Chandra, Abhishek; Chaudhry, Vidya Nair; Chaudhry, Prashaant; Ali, Akhtar; Mukherjee, Ashim; Mutsuddi, Mousumi

    2014-01-01

    Hyperhomocysteinemia induced by the C677T genetic variant in MTHFR (methylenetetrahydrofolate reductase) has been implicated in neuronal cell death of retinal ganglion cells (RGC), which is a characteristic feature of glaucoma. However, association of MTHFR C677T with glaucoma has been controversial because of inconsistent results across association studies. Association between MTHFR C677T and glaucoma has not been reported in Indian population. Therefore, with a focus on neurodegenerative death of RGC in glaucoma, the current study aimed to investigate association of MTHFR C677T with Primary Open Angle Glaucoma (POAG) and Primary Angle Closure Glaucoma (PACG) in a North Indian population. A total of 404 participants (231 patients and 173 controls) were included in this study. Genotyping was performed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism. A few random samples were also tested by direct sequencing. Genotypic and allelic distributions of the POAG and PACG cohorts were compared to that of controls by chi-square test and odds ratios were reported with 95% confidence intervals. Genotypic and allelic distributions between POAG cases and controls were significantly different (p?=?0.03 and p?=?0.01 respectively). Unlike POAG, we did not find significant difference in the genotypic and allelic distributions of C677T between PACG cases and controls (p>0.05). We also observed a higher proportion of TT associated POAG in females than that in males. However, this is a preliminary indication of gender specific risk of C677T that needs to be replicated in a larger cohort of males and females. The present investigation on MTHFR C677T and glaucoma reveals that the TT genotype and T allele of this polymorphism are significant risk factors for POAG but not for PACG in North Indian population. Ours is the first report demonstrating association of MTHFR C677T with POAG but not PACG in individuals from North India. PMID:25054348

  16. MTHFR 677C>T Polymorphism Increases the Male Infertility Risk: A Meta-Analysis Involving 26 Studies

    PubMed Central

    Gong, Mancheng; Dong, Wenjing; He, Tingyu; Shi, Zhirong; Huang, Guiying; Ren, Rui; Huang, Sichong; Qiu, Shaopeng; Yuan, Runqiang

    2015-01-01

    Background and Objectives Methylenetetrahydrofolate reductase (MTHFR) polymorphism may be a risk factor for male infertility. However, the epidemiologic studies showed inconsistent results regarding MTHFR polymorphism and the risk of male infertility. Therefore, we performed a meta-analysis of published case-control studies to re-examine the controversy. Methods Electronic searches of PubMed, EMBASE, Google Scholar and China National Knowledge Infrastructure (CNKI) were conducted to select eligible literatures for this meta-analysis (updated to June 19, 2014). According to our inclusion criteria and the Newcastle-Ottawa Scale (NOS), only high quality studies that observed the association between MTHFR polymorphism and male infertility risk were included. Crude odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of association between the MTHFR polymorphism and male infertility risk. Results Twenty-six studies involving 5,575 cases and 5,447 controls were recruited. Overall, MTHFR 677C>T polymorphism showed significant associations with male infertility risk in both fixed effects (CT+TT vs. CC: OR = 1.34, 95% CI: 1.23–1.46) and random effects models (CT+TT vs. CC: OR = 1.39, 95% CI: 1.19–1.62). Further, when stratified by ethnicity, sperm concentration and control sources, the similar results were observed in Asians, Caucasians, Azoo or OAT subgroup and both in population-based and hospital-based controls. Nevertheless, no significant association was only observed in oligo subgroup. Conclusions Our results indicated that the MTHFR polymorphism is associated with an increased risk of male infertility. Further well-designed analytical studies are necessary to confirm our conclusions and evaluate gene-environment interactions with male infertility risk. PMID:25793386

  17. Directed Evolution and Structural Analysis of NADPH-Dependent Acetoacetyl Coenzyme A (Acetoacetyl-CoA) Reductase from Ralstonia eutropha Reveals Two Mutations Responsible for Enhanced Kinetics

    PubMed Central

    Matsumoto, Ken'ichiro; Tanaka, Yoshikazu; Watanabe, Tsuyoshi; Motohashi, Ren; Ikeda, Koji; Tobitani, Kota; Yao, Min; Tanaka, Isao

    2013-01-01

    NADPH-dependent acetoacetyl-coenzyme A (acetoacetyl-CoA) reductase (PhaB) is a key enzyme in the synthesis of poly(3-hydroxybutyrate) [P(3HB)], along with ?-ketothiolase (PhaA) and polyhydroxyalkanoate synthase (PhaC). In this study, PhaB from Ralstonia eutropha was engineered by means of directed evolution consisting of an error-prone PCR-mediated mutagenesis and a P(3HB) accumulation-based in vivo screening system using Escherichia coli. From approximately 20,000 mutants, we obtained two mutant candidates bearing Gln47Leu (Q47L) and Thr173Ser (T173S) substitutions. The mutants exhibited kcat values that were 2.4-fold and 3.5-fold higher than that of the wild-type enzyme, respectively. In fact, the PhaB mutants did exhibit enhanced activity and P(3HB) accumulation when expressed in recombinant Corynebacterium glutamicum. Comparative three-dimensional structural analysis of wild-type PhaB and highly active PhaB mutants revealed that the beneficial mutations affected the flexibility around the active site, which in turn played an important role in substrate recognition. Furthermore, both the kinetic analysis and crystal structure data supported the conclusion that PhaB forms a ternary complex with NADPH and acetoacetyl-CoA. These results suggest that the mutations affected the interaction with substrates, resulting in the acquirement of enhanced activity. PMID:23913421

  18. Association between MTHFR C677T polymorphism and venous thromboembolism risk in the Chinese population: a meta-analysis of 24 case-controlled studies.

    PubMed

    Zhang, Peijin; Gao, Xiuyin; Zhang, Yanyan; Hu, Yuewen; Ma, He; Wang, Wei; Wang, Hui; Zhang, Jing; Xu, Hao; Lu, Zhaojun

    2015-05-01

    The association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and venous thromboembolism (VTE) risk in the Chinese population has been widely reported, but results were inconsistent and underpowered. To elucidate the variable results, a meta-analysis and systematic review were performed from all case-controlled studies relating MTHFR C677T polymorphism by pooling data on them. We estimated the pooled odds ratio with its 95% confidence intervals to assess this possible association. Finally, a total of 24 studies with 2339 cases and 4048 controls were included in the current meta-analysis. Significant association was found with VTE risk for all genetic models. Subgroup analyses by type of VTE further identified the above-mentioned association in deep vein thrombosis/pulmonary embolism and splanchnic vein thrombosis. The findings from our meta-analysis support the associations of MTHFR C677T polymorphism with VTE risk in the Chinese population. PMID:25149317

  19. Analysis of MTHFR and MTRR Gene Polymorphisms in Iranian Ventricular Septal Defect Subjects.

    PubMed

    Pishva, Seyyed Reza; Vasudevan, Ramachandran; Etemad, Ali; Heidari, Farzad; Komara, Makanko; Ismail, Patimah; Othman, Fauziah; Karimi, Abdollah; Sabri, Mohammad Reza

    2013-01-01

    Ventricular septal defect (VSD) is one of the most common types of congenital heart defects (CHD). There are vivid multifactorial causes for VSD in which both genetic and environmental risk factors are consequential in the development of CHD. Methionine synthase reductase (MTRR) and methylenetetrahydrofolate reductase (MTHFR) are two of the key regulatory enzymes involved in the metabolic pathway of homocysteine. Genes involved in homocysteine/folate metabolism may play an important role in CHDs. In this study; we determined the association of A66G and C524T polymorphisms of the MTRR gene and C677T polymorphism of the MTHFR gene in Iranian VSD subjects. A total of 123 children with VSDs and 125 healthy children were included in this study. Genomic DNA was extracted from the buccal cells of all the subjects. The restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP) method was carried out to amplify the A66G and C524T polymorphism of MTRR and C677T polymorphism of MTHFR genes digested with Hinf1, Xho1 and Nde1 enzymes, respectively. The genotype frequencies of CC, CT and TT of MTRR gene among the studied cases were 43.1%, 40.7% and 16.3%, respectively, compared to 52.8%, 43.2% and 4.0%, respectively among the controls. For the MTRR A66G gene polymorphism, the genotypes frequencies of AA, AG and GG among the cases were 33.3%, 43.9% and 22.8%, respectively, while the frequencies were 49.6%, 42.4% and 8.0%, respectively, among control subjects. The frequencies for CC and CT genotypes of the MTHFR gene were 51.2% and 48.8%, respectively, in VSD patients compared to 56.8% and 43.2% respectively, in control subjects. Apart from MTHFR C677T polymorphism, significant differences were noticed (p < 0.05) in C524T and A66G polymorphisms of the MTRR gene between cases and control subjects. PMID:23358257

  20. Analysis of MTHFR and MTRR Gene Polymorphisms in Iranian Ventricular Septal Defect Subjects

    PubMed Central

    Pishva, Seyyed Reza; Vasudevan, Ramachandran; Etemad, Ali; Heidari, Farzad; Komara, Makanko; Ismail, Patimah; Othman, Fauziah; Karimi, Abdollah; Sabri, Mohammad Reza

    2013-01-01

    Ventricular septal defect (VSD) is one of the most common types of congenital heart defects (CHD). There are vivid multifactorial causes for VSD in which both genetic and environmental risk factors are consequential in the development of CHD. Methionine synthase reductase (MTRR) and methylenetetrahydrofolate reductase (MTHFR) are two of the key regulatory enzymes involved in the metabolic pathway of homocysteine. Genes involved in homocysteine/folate metabolism may play an important role in CHDs. In this study; we determined the association of A66G and C524T polymorphisms of the MTRR gene and C677T polymorphism of the MTHFR gene in Iranian VSD subjects. A total of 123 children with VSDs and 125 healthy children were included in this study. Genomic DNA was extracted from the buccal cells of all the subjects. The restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP) method was carried out to amplify the A66G and C524T polymorphism of MTRR and C677T polymorphism of MTHFR genes digested with Hinf1, Xho1 and Nde1 enzymes, respectively. The genotype frequencies of CC, CT and TT of MTRR gene among the studied cases were 43.1%, 40.7% and 16.3%, respectively, compared to 52.8%, 43.2% and 4.0%, respectively among the controls. For the MTRR A66G gene polymorphism, the genotypes frequencies of AA, AG and GG among the cases were 33.3%, 43.9% and 22.8%, respectively, while the frequencies were 49.6%, 42.4% and 8.0%, respectively, among control subjects. The frequencies for CC and CT genotypes of the MTHFR gene were 51.2% and 48.8%, respectively, in VSD patients compared to 56.8% and 43.2% respectively, in control subjects. Apart from MTHFR C677T polymorphism, significant differences were noticed (p < 0.05) in C524T and A66G polymorphisms of the MTRR gene between cases and control subjects. PMID:23358257

  1. Contribution of GSTM1, GSTT1, and MTHFR polymorphisms to end-stage renal disease of unknown etiology in Mexicans

    PubMed Central

    Gutiérrez-Amavizca, B. E.; Orozco-Castellanos, R.; Ortíz-Orozco, R.; Padilla-Gutiérrez, J.; Valle, Y.; Gutiérrez-Gutiérrez, N.; García-García, G.; Gallegos-Arreola, M.; Figuera, L. E.

    2013-01-01

    Oxidative stress is increased in chronic kidney disease, owing to an imbalance between the oxidative and antioxidant pathways as well as a state of persistent hyperhomocysteinemia. The enzymes glutathione S-transferases (GSTs) and methylenetetrahydrofolate reductase (MTHFR) are implicated in the regulation of these pathways. This study investigates the association between polymorphisms in the Glutathione S-transferase Mu 1 (GSTM1), glutathione S-transferase theta 1 (GSTT1), and MTHFR genes and end-stage renal disease (ESRD) of unknown etiology in patients in Mexico. A Case-control study included 110 ESRD patients and 125 healthy individuals. GSTM1 and GSTT1 genotypes were determined using the multiplex polymerase chain reaction (PCR). The MTHFR C677T polymorphism was studied using a PCR/restriction fragment length polymorphism method. In ESRD patients, GSTM1 and GSTT1 null genotype frequencies were 61% and 7% respectively. GSTM1 genotype frequencies differed significantly between groups, showing that homozygous deletion of the GSTM1 gene was associated with susceptibility to ESRD of unknown etiology (P = 0.007, odds ratios = 2.05, 95% confidence interval 1.21-3.45). The MTHFR C677T polymorphism genotype and allele distributions were similar in both groups (P > 0.05), and the CT genotype was the most common genotype in both groups (45.5% and 46.6%). Our findings suggest that the GSTM1 null polymorphism appears to be associated with the ESRD of unknown etiology in patients in Mexico. PMID:24339523

  2. Significant Impact of the MTHFR Polymorphisms and Haplotypes on Male Infertility Risk

    PubMed Central

    Gupta, Nishi; Sarkar, Saumya; David, Archana; Gangwar, Pravin Kumar; Gupta, Richa; Khanna, Gita; Sankhwar, Satya Narayan; Khanna, Anil; Rajender, Singh

    2013-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR) converts 5,10-methylene tetrahydrofolate to 5-methyl tetrahydrofolate and affects the activity of cellular cycles participating in nucleotide synthesis, DNA repair, genome stability, maintenance of methyl pool, and gene regulation. Genetically compromised MTHFR activity has been suggested to affect male fertility. The objective of the present study was to find the impact on infertility risk of c.203G>A, c.1298A>C, and c.1793G>A polymorphisms in the MTHFR gene. Methods PCR-RFLP and DNA sequencing were used to genotype the common SNPs in the MTHFR gene in 630 infertile and 250 fertile males. Chi-square test was applied for statistical comparison of genotype data. Linkage disequilibrium between the SNPs and the frequency of common haplotypes were assessed using Haploview software. Biochemical levels of total homocysteine (tHcy) and folic acid were measured. Meta-analysis on c.1298A>C polymorphism was performed using data from ten studies, comprising 2734 cases and 2737 controls. Results c.203G>A and c.1298A>C were found to be unrelated to infertility risk. c.1793G>A was protective against infertility (P?=?0.0008). c.677C>T and c.1793G>A were in significant LD (D’?=?0.9). Folic acid and tHcy level did not correlate with male infertility. Pooled estimate on c.1298A>C data from all published studies including our data showed no association of this polymorphism with male infertility (Odds ratio?=?1.035, P?=?0.56), azoospermia (Odds ratio?=?0.97, P?=?0.74), or oligoasthenoteratozoospermia (Odds ratio?=?0.92, p?=?0.29). Eight haplotypes with more than 1% frequency were detected, of which CCGA was protective against infertility (p?=?0.02), but the significance of the latter was not seen after applying Bonferroni correction. Conclusion Among MTHFR polymorphisms, c.203G>A and c.1298A>C do not affect infertility risk and c.1793G>A is protective against infertility. Haplotype analysis suggested that risk factors on the MTHFR locus do not extend too long on the DNA string. PMID:23874907

  3. New insights into the catalytic mechanism of vitamin K epoxide reductase (VKORC1) – The catalytic properties of the major mutations of rVKORC1 explain the biological cost associated to mutations?

    PubMed Central

    Matagrin, Benjamin; Hodroge, Ahmed; Montagut-Romans, Adrien; Andru, Julie; Fourel, Isabelle; Besse, Stéphane; Benoit, Etienne; Lattard, Virginie

    2013-01-01

    The systematic use of antivitamin K anticoagulants (AVK) as rodenticides caused the selection of rats resistant to AVKs. The resistance is mainly associated to genetic polymorphisms in the Vkorc1 gene encoding the VKORC1 enzyme responsible for the reduction of vitamin K 2,3-epoxide to vitamin K. Five major mutations, which are responsible for AVK resistance, have been described. Possible explanations for the biological cost of these mutations have been suggested. This biological cost might be linked to an increase in the vitamin K requirements. To analyze the possible involvement of VKORC1 in this biological cost, rVKORC1 and its major mutants were expressed in Pichia pastoris as membrane-bound proteins and their catalytic properties were determined for vitamin K and 3-OH-vitamin K production. In this report, we showed that mutations at Leu-120 and Tyr-139 dramatically affect the vitamin K epoxide reductase activity. Moreover, this study allowed the detection of an additional production of 3-hydroxyvitamin K for all the mutants in position 139. This result suggests the involvement of Tyr-139 residue in the second half-step of the catalytic mechanism corresponding to the dehydration of vitamin K epoxide. As a consequence, the biological cost observed in Y139C and Y139S resistant rat strains is at least partially explained by the catalytic properties of the mutated VKORC1 involving a loss of vitamin K from the vitamin K cycle through the formation of 3-hydroxyvitamin K and a very low catalytic efficiency of the VKOR activity. PMID:23772386

  4. New insights into the catalytic mechanism of vitamin K epoxide reductase (VKORC1) - The catalytic properties of the major mutations of rVKORC1 explain the biological cost associated to mutations.

    PubMed

    Matagrin, Benjamin; Hodroge, Ahmed; Montagut-Romans, Adrien; Andru, Julie; Fourel, Isabelle; Besse, Stéphane; Benoit, Etienne; Lattard, Virginie

    2013-01-01

    The systematic use of antivitamin K anticoagulants (AVK) as rodenticides caused the selection of rats resistant to AVKs. The resistance is mainly associated to genetic polymorphisms in the Vkorc1 gene encoding the VKORC1 enzyme responsible for the reduction of vitamin K 2,3-epoxide to vitamin K. Five major mutations, which are responsible for AVK resistance, have been described. Possible explanations for the biological cost of these mutations have been suggested. This biological cost might be linked to an increase in the vitamin K requirements. To analyze the possible involvement of VKORC1 in this biological cost, rVKORC1 and its major mutants were expressed in Pichia pastoris as membrane-bound proteins and their catalytic properties were determined for vitamin K and 3-OH-vitamin K production. In this report, we showed that mutations at Leu-120 and Tyr-139 dramatically affect the vitamin K epoxide reductase activity. Moreover, this study allowed the detection of an additional production of 3-hydroxyvitamin K for all the mutants in position 139. This result suggests the involvement of Tyr-139 residue in the second half-step of the catalytic mechanism corresponding to the dehydration of vitamin K epoxide. As a consequence, the biological cost observed in Y139C and Y139S resistant rat strains is at least partially explained by the catalytic properties of the mutated VKORC1 involving a loss of vitamin K from the vitamin K cycle through the formation of 3-hydroxyvitamin K and a very low catalytic efficiency of the VKOR activity. PMID:23772386

  5. MTHFR Polymorphisms, Folate Intake, and Carcinogen DNA Adducts in the Lung

    PubMed Central

    Lee, Mi-Sun; Asomaning, Kofi; Su, Li; Wain, John C.; Mark, Eugene J.; Christiani, David C.

    2011-01-01

    The methylenetetrahydrofolate reductase (MTHFR) genes and folate in one-carbon metabolism are essential for DNA methylation and synthesis. However, their role in carcinogen DNA damage in target lung tissue, a dosimeter for cancer risk, is not known. Our study aimed to investigate the association between genetic and nutritional one-carbon metabolism factors and DNA adducts in target lung. Data on 135 lung cancer cases from the Massachusetts General Hospital were studied. Genotyping was completed for MTHFR C677T (rs1801133) and A1298C (rs1801131). Information on dietary intake for one-carbon related micronutrients, folate and other B vitamin, was derived from a validated food frequency questionnaire. DNA adducts in lung were measured by 32P-postlabeling. After adjusting for potential confounders, DNA adduct levels in lung significantly increased by 69.2% [95% confidence interval (CI), 5.5% to 171.5%] for the MTHFR 1298AC+CC genotype. The high risk group, combining the A1298C (AC+CC) plus C677T (CT+TT) genotypes, had significantly enhanced levels of lung adducts by 210.7% (95% CI, 21.4% to 695.2%) in contrast to the A1298C (AA) plus C677T (CC) genotypes. Elevation of DNA adduct was pronounced - 111.3% (95% CI, ?3.0 to 360.5%) among 1298AC+CC patients who consumed the lowest level of folate intake as compared with 1298AA individuals with highest tertile of intake. These results indicate that DNA adducts levels are influenced by MTHFR polymorphisms and low folate consumption, suggesting an important role of genetic and nutritional factors in protecting DNA damage from lung carcinogen in at-risk populations. PMID:22052259

  6. Meta-analysis of the association of MTHFR polymorphisms with multiple myeloma risk.

    PubMed

    Ma, Li-Min; Ruan, Lin-Hai; Yang, Hai-Ping

    2015-01-01

    The association of methylenetetrahydrofolate reductase (MTHFR) polymorphisms with multiple myeloma (MM) risk has been explored, but the results remain controversial. Thus, a meta-analysis was performed to provide a comprehensively estimate. The case-control studies about MTHFR C677T and A1298C polymorphisms with MM risk were collected by searching PubMed, Elsevier, China National Knowledge Infrastructure and Wanfang Databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were applied to assess the strength of association. Overall, no significant association was found between MTHFR A1298C polymorphism and MM risk under all four genetic models (AC vs. AA, OR?=?0.99, 95%CI?=?0.82-1.20; CC vs. AA, OR?=?1.14, 95%CI?=?0.77-1.68; recessive model, OR?=?1.10, 95%CI?=?0.76-1.59; dominant model, OR?=?1.01, 95%CI?=?0.84-1.22). The risk was also not significantly altered for C677T polymorphism and MM in overall comparisons (CT vs. CC, OR?=?1.04, 95%CI?=?0.93-1.17; TT vs. CC, OR?=?1.16, 95%CI?=?0.98-1.37; recessive model, OR?=?1.13, 95%CI?=?0.98-1.32; dominant model, OR?=?1.07, 95%CI?=?0.96-1.20). In subgroup analyses by ethnicity, no significant association was observed in both Caucasians and Asians. This meta-analysis suggested that MTHFR polymorphisms were not associated with MM risk. PMID:26022785

  7. Homocysteine levels are associated with MTHFR A1298C polymorphism in Indian population.

    PubMed

    Kumar, Jitender; Das, Swapan K; Sharma, Priyanka; Karthikeyan, Ganesan; Ramakrishnan, Lakshmy; Sengupta, Shantanu

    2005-01-01

    An elevated level of homocysteine is an independent risk factor for cardiovascular diseases and is associated with other complex disorders. Homocysteine levels can be elevated due to dietary and/or genetic factors. A majority of Indian population have a low level of vitamin B12 (presumably due to vegetarian diet)--a critical nutritional factor, deficiency of which results in hyperhomocysteinemia. Hence, polymorphisms in the genes responsible for homocysteine metabolism can be perceived to have a greater impact in relation to hyperhomocysteinemia in Indian population. For this reason, the effects of diet and/or methylenetetrahydrofolate reductase (MTHFR) polymorphism were assessed in 200 individuals having varying homocysteine levels. Homocysteine levels were significantly elevated in individuals adhering to a vegetarian diet (P = 0.019) or having MTHFR A1298C polymorphism (P = 0.006). The minor allele frequency (MAF) of MTHFR C677T and A1298C was 0.15 and 0.44 respectively in this cohort. Since the MAF of these polymorphisms differed considerably from Caucasian and other Asian populations, frequencies of these polymorphisms were also determined in more than 400 individuals from different ethnic populations, selected from the entire country based on their geographical location and linguistic lineage, and was found to be similar to that of our cohort. The fact that MTHFR A1298C polymorphism is significantly associated with homocysteine levels, and that the CC genotype is present at a higher frequency in the Indian population, makes it extremely relevant in terms of its potential impact on hyperhomocysteinemia. PMID:16244782

  8. Meta-analysis of the association of MTHFR polymorphisms with multiple myeloma risk

    PubMed Central

    Ma, Li-Min; Ruan, Lin-Hai; Yang, Hai-Ping

    2015-01-01

    The association of methylenetetrahydrofolate reductase (MTHFR) polymorphisms with multiple myeloma (MM) risk has been explored, but the results remain controversial. Thus, a meta-analysis was performed to provide a comprehensively estimate. The case-control studies about MTHFR C677T and A1298C polymorphisms with MM risk were collected by searching PubMed, Elsevier, China National Knowledge Infrastructure and Wanfang Databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were applied to assess the strength of association. Overall, no significant association was found between MTHFR A1298C polymorphism and MM risk under all four genetic models (AC vs. AA, OR?=?0.99, 95%CI?=?0.82-1.20; CC vs. AA, OR?=?1.14, 95%CI?=?0.77-1.68; recessive model, OR?=?1.10, 95%CI?=?0.76-1.59; dominant model, OR?=?1.01, 95%CI?=?0.84-1.22). The risk was also not significantly altered for C677T polymorphism and MM in overall comparisons (CT vs. CC, OR?=?1.04, 95%CI?=?0.93-1.17; TT vs. CC, OR?=?1.16, 95%CI?=?0.98-1.37; recessive model, OR?=?1.13, 95%CI?=?0.98-1.32; dominant model, OR?=?1.07, 95%CI?=?0.96-1.20). In subgroup analyses by ethnicity, no significant association was observed in both Caucasians and Asians. This meta-analysis suggested that MTHFR polymorphisms were not associated with MM risk. PMID:26022785

  9. The Association between MTHFR Gene Polymorphisms and Hepatocellular Carcinoma Risk: A Meta-Analysis

    PubMed Central

    Deng, Yan; Huang, Shan; Xu, Juanjuan; Li, Haiwei; Li, Shan; Zhao, Jinmin

    2013-01-01

    Background The association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and hepatocellular carcinoma (HCC) risk was inconsistent and underpowered. To clarify the effects of MTHFR gene polymorphisms on the risk of HCC, a meta-analysis of all available studies relating C677T and/or A1298C polymorphisms of MTHFR gene to the risk of HCC was conducted. Methods The authors searched PubMed, EMBASE, Cochrane Library, Web of Science, and Chinese Biomedical Literature database (CBM) for the period up to July 2012. Data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) was calculated. Metaregression and subgroup analyses were performed to identify the source of heterogeneity. Results Finally, 12 studies with 2,351 cases and 4,091 controls were included for C677T polymorphism and 6 studies with 1,333 cases and 1,878 controls were included for A1298C polymorphism. With respect to A1298C polymorphism, significantly decreased HCC risk was found in the overall population (CC vs. AA: OR?=?0.660, 95%CI 0.460–0.946, P?=?0.024; recessive model: OR?=?0.667, 95%CI?=?0.470–0.948, P?=?0.024). In subgroup analyses, significantly decreased HCC risk was found in Asian population (CC vs. AA: OR?=?0.647, 95%CI?=?0.435–0.963; P?=?0.032) and population-based studies (CC vs. AA: OR?=?0.519, 95%CI?=?0.327–0.823; P?=?0.005). With respect to C677T polymorphism, no significant association with HCC risk was demonstrated in overall and stratified analyses. Conclusions We concluded that MTHFR A1298C polymorphism may play a protective role in the carcinogenesis of HCC. Further large and well-designed studies are needed to confirm this association. PMID:23457501

  10. Methylenetetrahydrofolate reductase polymorphism interacts with riboflavin intake to influence bone mineral density

    Microsoft Academic Search

    H. M. Macdonald; F. E. McGuigan; W. D. Fraser; S. A. New; S. H. Ralston; D. M. Reid

    2004-01-01

    Bone mineral density is a complex trait regulated by an interaction between genetic and environmental factors. Recent studies have identified a functional polymorphism affecting codon 677 of the methylenetetrahydrofolate reductase (MTHFR) gene that is associated with reduced bone mineral density (BMD) in Japanese and Danish postmenopausal women and increased risk of fracture in elderly Danish women. Since dietary B vitamins

  11. Folate Intake, MTHFR Polymorphisms, and the Risk of Colorectal Cancer: A Systematic Review and Meta-Analysis

    PubMed Central

    Kennedy, Deborah A.; Stern, Seth J.; Matok, Ilan; Moretti, Myla E.; Sarkar, Moumita; Adams-Webber, Thomasin; Koren, Gideon

    2012-01-01

    Background. The objective was to determine whether relationships exist between the methylene-tetrahydrofolate reductase (MTHFR) polymorphisms and risk of colorectal cancer (CRC) and examine whether the risk is modified by level of folate intake. Methods. MEDLINE, Embase, and SCOPUS were searched to May 2012 using the terms “folic acid,” “folate,” “colorectal cancer,” “methylenetetrahydrofolate reductase,” “MTHFR.” Observational studies were included which (1) assessed the risk of CRC for each polymorphism and/or (2) had defined levels of folate intake for each polymorphism and assessed the risk of CRC. Results. From 910 references, 67 studies met our criteria; hand searching yielded 10 studies. The summary risk estimate comparing the 677CT versus CC genotype was 1.02 (95% CI 0.95–1.10) and for 677TT versus CC was 0.88 (95% CI 0.80–0.96) both with heterogeneity. The summary risk estimates for A1298C polymorphisms suggested no reduced risk. The summary risk estimate for high versus low total folate for the 677CC genotype was 0.70 (95% CI 0.56–0.89) and the 677TT genotype 0.63 (95% CI 0.41–0.97). Conclusion. These results suggest that the 677TT genotype is associated with a reduced risk of developing CRC, under conditions of high total folate intake, and this associated risk remains reduced for both MTHFR 677 CC and TT genotypes. PMID:23125859

  12. MTHFR deficiency or reduced intake of folate or choline in pregnant mice results in impaired short-term memory and increased apoptosis in the hippocampus of wild-type offspring.

    PubMed

    Jadavji, N M; Deng, L; Malysheva, O; Caudill, M A; Rozen, R

    2015-08-01

    Genetic or nutritional disturbances in one-carbon metabolism, with associated hyperhomocysteinemia, can result in complex disorders including pregnancy complications and neuropsychiatric diseases. In earlier work, we showed that mice with a complete deficiency of methylenetetrahydrofolate reductase (MTHFR), a critical enzyme in folate and homocysteine metabolism, had cognitive impairment with disturbances in choline metabolism. Maternal demands for folate and choline are increased during pregnancy and deficiencies of these nutrients result in several negative outcomes including increased resorption and delayed development. The goal of this study was to investigate the behavioral and neurobiological impact of a maternal genetic deficiency in MTHFR or maternal nutritional deficiency of folate or choline during pregnancy on 3-week-old Mthfr(+/+) offspring. Mthfr(+/+) and Mthfr(+/-) females were placed on control diets (CD); and Mthfr(+/+) females were placed on folate-deficient diets (FD) or choline-deficient diets (ChDD) throughout pregnancy and lactation until their offspring were 3weeks of age. Short-term memory was assessed in offspring, and hippocampal tissue was evaluated for morphological changes, apoptosis, proliferation and choline metabolism. Maternal MTHFR deficiency resulted in short-term memory impairment in offspring. These dams had elevated levels of plasma homocysteine when compared with wild-type dams. There were no differences in plasma homocysteine in offspring. Increased apoptosis and proliferation was observed in the hippocampus of offspring from Mthfr(+/-) mothers. In the maternal FD and ChDD study, offspring also showed short-term memory impairment with increased apoptosis in the hippocampus; increased neurogenesis was observed in ChDD offspring. Choline acetyltransferase protein was increased in the offspring hippocampus of both dietary groups and betaine was decreased in the hippocampus of FD offspring. Our results reveal short-term memory deficits in the offspring of dams with MTHFR deficiency or dietary deficiencies of critical methyl donors. We suggest that deficiencies in maternal one-carbon metabolism during pregnancy can contribute to hippocampal dysfunction in offspring through apoptosis or altered choline metabolism. PMID:25956258

  13. Association of the Maternal MTHFR C677T Polymorphism with Susceptibility to Neural Tube Defects in Offsprings: Evidence from 25 Case-Control Studies

    PubMed Central

    Zou, Peng; Ji, Guixiang; Gu, Aihua; Zhao, Peng

    2012-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in folate metabolism and is involved in DNA methylation, DNA synthesis, and DNA repair. In addition, it is a possible risk factor in neural tube defects (NTDs). The association of the C677T polymorphism in the MTHFR gene and NTD susceptibility has been widely demonstrated, but the results remain inconclusive. In this study, we performed a meta-analysis with 2429 cases and 3570 controls to investigate the effect of the MTHFR C677T polymorphism on NTDs. Methods An electronic search of PubMed and Embase database for papers on the MTHFR C677T polymorphism and NTD risk was performed. All data were analysed with STATA (version 11). Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. Sensitivity analysis, test of heterogeneity, cumulative meta-analysis, and assessment of bias were performed in our meta-analysis. Results A significant association between the MTHFR C677T polymorphism and NTD susceptibility was revealed in our meta-analysis ( TT versus CC: OR ?=?2.022, 95% CI: 1.508, 2.712; CT+TT versus CC: OR ?=?1.303, 95% CI: 1.089, 1.558; TT versus CC+CT: OR ?=?1.716, 95% CI: 1.448, 2.033; 2TT+CT versus 2CC+CT: OR ?=?1.330, 95% CI: 1.160, 1.525). Moreover, an increased NTD risk was found after stratification of the MTHFR C677T variant data by ethnicity and source of controls. Conclusion The results suggested the maternal MTHFR C677T polymorphism is a genetic risk factor for NTDs. Further functional studies to investigate folate-related gene polymorphisms, periconceptional multivitamin supplements, complex interactions, and the development of NTDs are warranted. PMID:23056169

  14. [Construction of adeno-associated virus vector carried mutated dihydrofolate reductase and green fluorescent protein and its expression in NIH3T3 cells].

    PubMed

    Li, Li-Bo; Feng, Ru; Zhou, Shu-Yun

    2002-06-01

    The aim of this study was to construct recombinant mDHFR-GFP/AAV vector containing mutated dihydrofolate reductase (mDHFR) and green fluorescent protein (GFP) fusion genes and its expression in NIH3T3 cells, to investigate the resistance of the cells to methotrexate. Amplified cDNA of mDHFR and GFP segmented from their plasmid separately were linked by PCR with the aminoacetic acid linker. The fusion gene was inserted into T vector, and after enzyme cutting the fusion gene fragment was inserted into AAV vector, then packaging the vector into recombined AAV and infected NIH3T3 cells. Expression of gene fusion was observed by PCR, fluorescent microscopy and flow cytometry. mDHFR and GFP cDNA were found in NIH3T3 genomic DNA, the GFP expression rate was about 25%, and resistance of the transferred cells to MTX was increased markedly. The results showed that AAV vector can transfer mDHFR and GFP fusion gene into NIH3T3 cells and increase resistance to MTX in gene modified cells. This data provided a basis for application of mDHFR and AAV vector in gene therapy. PMID:12513788

  15. Mutation of the Inducible ARABIDOPSIS THALIANA CYTOCHROME P450 REDUCTASE2 Alters Lignin Composition and Improves Saccharification1[W][OPEN

    PubMed Central

    Sundin, Lisa; Vanholme, Ruben; Geerinck, Jan; Goeminne, Geert; Höfer, René; Kim, Hoon; Ralph, John; Boerjan, Wout

    2014-01-01

    ARABIDOPSIS THALIANA CYTOCHROME P450 REDUCTASE1 (ATR1) and ATR2 provide electrons from NADPH to a large number of CYTOCHROME P450 (CYP450) enzymes in Arabidopsis (Arabidopsis thaliana). Whereas ATR1 is constitutively expressed, the expression of ATR2 appears to be induced during lignin biosynthesis and upon stresses. Therefore, ATR2 was hypothesized to be preferentially involved in providing electrons to the three CYP450s involved in lignin biosynthesis: CINNAMATE 4-HYDROXYLASE (C4H), p-COUMARATE 3-HYDROXYLASE1 (C3H1), and FERULATE 5-HYDROXYLASE1 (F5H1). Here, we show that the atr2 mutation resulted in a 6% reduction in total lignin amount in the main inflorescence stem and a compositional shift of the remaining lignin to a 10-fold higher fraction of p-hydroxyphenyl units at the expense of syringyl units. Phenolic profiling revealed shifts in lignin-related phenolic metabolites, in particular with the substrates of C4H, C3H1 and F5H1 accumulating in atr2 mutants. Glucosinolate and flavonol glycoside biosynthesis, both of which also rely on CYP450 activities, appeared less affected. The cellulose in the atr2 inflorescence stems was more susceptible to enzymatic hydrolysis after alkaline pretreatment, making ATR2 a potential target for engineering plant cell walls for biofuel production. PMID:25315601

  16. Mutation of the light-induced yellow leaf 1 gene, which encodes a geranylgeranyl reductase, affects chlorophyll biosynthesis and light sensitivity in rice.

    PubMed

    Zhou, Yong; Gong, Zhiyun; Yang, Zefeng; Yuan, Yuan; Zhu, Jinyan; Wang, Man; Yuan, Fuhai; Wu, Shujun; Wang, Zhiqin; Yi, Chuandeng; Xu, Tinghua; Ryom, MyongChol; Gu, Minghong; Liang, Guohua

    2013-01-01

    Chlorophylls (Chls) are crucial for capturing light energy for photosynthesis. Although several genes responsible for Chl biosynthesis were characterized in rice (Oryza sativa), the genetic properties of the hydrogenating enzyme involved in the final step of Chl synthesis remain unknown. In this study, we characterized a rice light-induced yellow leaf 1-1 (lyl1-1) mutant that is hypersensitive to high-light and defective in the Chl synthesis. Light-shading experiment suggested that the yellowing of lyl1-1 is light-induced. Map-based cloning of LYL1 revealed that it encodes a geranylgeranyl reductase. The mutation of LYL1 led to the majority of Chl molecules are conjugated with an unsaturated geranylgeraniol side chain. LYL1 is the firstly defined gene involved in the reduction step from Chl-geranylgeranylated (Chl(GG)) and geranylgeranyl pyrophosphate (GGPP) to Chl-phytol (Chl(Phy)) and phytyl pyrophosphate (PPP) in rice. LYL1 can be induced by light and suppressed by darkness which is consistent with its potential biological functions. Additionally, the lyl1-1 mutant suffered from severe photooxidative damage and displayed a drastic reduction in the levels of ?-tocopherol and photosynthetic proteins. We concluded that LYL1 also plays an important role in response to high-light in rice. PMID:24058671

  17. Mutation for Nonsyndromic Mental Retardation in the trans-2-Enoyl-CoA Reductase TER Gene Involved in Fatty Acid Elongation Impairs the Enzyme Activity and Stability, Leading to Change in Sphingolipid Profile*

    PubMed Central

    Abe, Kensuke; Ohno, Yusuke; Sassa, Takayuki; Taguchi, Ryo; Çal??kan, Minal; Ober, Carole; Kihara, Akio

    2013-01-01

    Very long-chain fatty acids (VLCFAs, chain length >C20) exist in tissues throughout the body and are synthesized by repetition of the fatty acid (FA) elongation cycle composed of four successive enzymatic reactions. In mammals, the TER gene is the only gene encoding trans-2-enoyl-CoA reductase, which catalyzes the fourth reaction in the FA elongation cycle. The TER P182L mutation is the pathogenic mutation for nonsyndromic mental retardation. This mutation substitutes a leucine for a proline residue at amino acid 182 in the TER enzyme. Currently, the mechanism by which the TER P182L mutation causes nonsyndromic mental retardation is unknown. To understand the effect of this mutation on the TER enzyme and VLCFA synthesis, we have biochemically characterized the TER P182L mutant enzyme using yeast and mammalian cells transfected with the TER P182L mutant gene and analyzed the FA elongation cycle in the B-lymphoblastoid cell line with the homozygous TER P182L mutation (TERP182L/P182L B-lymphoblastoid cell line). We have found that TER P182L mutant enzyme exhibits reduced trans-2-enoyl-CoA reductase activity and protein stability, thereby impairing VLCFA synthesis and, in turn, altering the sphingolipid profile (i.e. decreased level of C24 sphingomyelin and C24 ceramide) in the TERP182L/P182L B-lymphoblastoid cell line. We have also found that in addition to the TER enzyme-catalyzed fourth reaction, the third reaction in the FA elongation cycle is affected by the TER P182L mutation. These findings provide new insight into the biochemical defects associated with this genetic mutation. PMID:24220030

  18. General and oxidative stress responses in Bacillus subtilis: cloning, expression, and mutation of the alkyl hydroperoxide reductase operon.

    PubMed Central

    Antelmann, H; Engelmann, S; Schmid, R; Hecker, M

    1996-01-01

    The AhpC subunit of the Bacillus subtilis alkyl hydroperoxide reductase was identified as a general stress protein induced in response to heat or salt stress or after entry of the organism into the stationary phase. The ahp operon, encoding the two subunits AhpC and AhpF, was cloned and localized between the gntRKPZ operon and the bglA locus. Two-dimensional gel analyses revealed an especially strong induction of AhpC and AhpF in cells subjected to oxidative stress. Transcriptional studies showed a 3- to 4-fold induction of ahp mRNA after heat or salt stress or starvation for glucose and a 20-fold induction by oxidative stress, thus confirming the protein induction data for AhpC and AhpF. Stress induction occurred at a sigmaA-dependent promoter that overlaps with operator sites similar to the per box. Compared with the wild type, the ahpC mutant was resistant to hydrogen peroxide because of the derepression of the peroxide regulon (N. Bsat, L. Chen, and J. D. Helmann, J. Bacteriol. 178:6579-6586, 1996) but more sensitive to cumene hydroperoxide (CHP) during exponential growth. In contrast, stationary-phase wild-type and ahpC mutant cells displayed complete resistance to treatment with 1 mM CHP. Moreover, a sigmaB mutant was found to be extremely sensitive to CHP during vegetative growth and in stationary phase, which indicates that sigmaB-dependent general stress proteins are involved in the protection of cells against oxidative stress. PMID:8932314

  19. Association of MTHFR C677T with total homocysteine plasma levels and susceptibility to Parkinson's disease: a meta-analysis.

    PubMed

    Zhu, Ying; Zhu, Rui-Xia; He, Zhi-Yi; Liu, Xu; Liu, He-Nan

    2015-06-01

    The C677T single-nucleotide polymorphism in the methylenetetrahydrofolate reductase gene (MTHFR) may elevate homocysteine (Hcy) levels and increase the risk of Parkinson's disease (PD); however, results are conflicting. Our aim was to resolve contradictions in the literature and to determine whether MTHFR C677T has a significant role in regulating Hcy levels and/or is a significant risk factor for PD. MEDLINE, EMBASE, the Cochrane Library, China Biological Medicine Database and Google Scholar were searched until May 2014. Strict selection and exclusion criteria were determined, and odds ratios (ORs)/weighted mean differences (WMDs) with 95 % confidence intervals (CIs) were used to assess the strength of associations. Statistical analyses were performed using STATA 12.0. Fifteen studies that together assessed 2690 PD cases and 8465 controls were included. Meta-analysis showed that no significant difference in the distribution of MTHFR C677T between PD cases and controls was found. While stratifying for ethnicity, significant association was revealed in Europeans (T vs. C, OR = 1.17, 95 % CIs 1.04-1.31) but not in Asians. Significant association between the T allele and increased Hcy levels was found in PD cases and controls; Hcy levels were higher in PD cases and controls carrying the MTHFR T677 allele than in non-carriers (TT vs. CC, PD WMD = 6.50, 95 % CIs 6.20-6.80; controls WMD = 4.52, 95 % CIs 4.24-4.80). Other within-group comparisons showed similar results. This meta-analysis suggests that MTHFR C667T may confer PD susceptibility in Europeans. The T allele may be an independent risk factor for elevated Hcy levels in PD patients. PMID:25564416

  20. MTHFR 677C ? T genotype disrupts prefrontal function in schizophrenia through an interaction with COMT 158Val ? Met

    PubMed Central

    Roffman, Joshua L.; Gollub, Randy L.; Calhoun, Vince D.; Wassink, Thomas H.; Weiss, Anthony P.; Ho, Beng C.; White, Tonya; Clark, Vincent P.; Fries, Jill; Andreasen, Nancy C.; Goff, Donald C.; Manoach, Dara S.

    2008-01-01

    Understanding how risk genes cumulatively impair brain function in schizophrenia could provide critical insights into its pathophysiology. Working memory impairment in schizophrenia has been associated with abnormal dopamine signaling in the prefrontal cortex, which is likely under complex genetic control. The catechol-O-methyltransferase (COMT) 158Val ? Met polymorphism (rs4680), which affects the availability of prefrontal dopamine signaling, consistently stratifies prefrontal activation during working memory performance. However, the low-dopamine COMT 158Val allele does not confer increased risk for schizophrenia, and its effects on prefrontal function are not specific to the disorder. In the setting of other genetic variants influencing prefrontal dopamine signaling, COMT 158Val ? Met genotype may exert disease-specific effects. A second polymorphism, methylenetetrahydrofolate reductase (MTHFR) 677C ? T (rs1801133), has been associated with overall schizophrenia risk and executive function impairment in patients, and may influence dopamine signaling through mechanisms upstream of COMT effects. We found that the hypofunctional 677T variant was associated with decreased working memory load-dependent activation in the prefrontal and insular cortices in 79 schizophrenia patients, but not in 75 demographically matched healthy controls. Further, significant MTHFR × COMT genotype interactions were observed, which differed by diagnostic group: Reduced prefrontal activation was associated with the 677T and 158Val alleles in patients, but with 677C/C and 158Met/Met genotype in controls. These findings are consistent with epistatic effects of the COMT and MTHFR polymorphisms on prefrontal dopamine signaling, and suggest that in schizophrenia patients, the MTHFR 677T allele exacerbates prefrontal dopamine deficiency. The findings also suggest the importance of weighing COMT effects on prefrontal function within the context of MTHFR genotype. PMID:18988738

  1. Implications on human fertility of the 677C->T and 1298A->C polymorphisms of the MTHFR gene: consequences of a possible genetic selection

    Microsoft Academic Search

    A. Reyes-Engel; E. Munoz; M. J. Gaitan; E. Fabre; M. Gallo; J. L. Dieguez; M. Ruiz; M. Morell

    2002-01-01

    Mutant alleles with the 677C?T and 1298A?C polymorphisms of the MTHFR gene, and consequent lower methylentetrahydro- folate reductase enzyme activity, have been related to higher plasma homocysteine levels, which are associated with cardiovascular diseases. We assessed the genotype frequencies, degrees of fertility and homocysteine levels, and discuss a possible genetic selection for the gene polymorphisms studied. A total of 1777

  2. Association between MTHFR C677T, MTHFR A1298C and MS A2756G polymorphisms and risk of cervical intraepithelial neoplasia II/III and cervical cancer: a meta-analysis.

    PubMed

    Zhu, Jie; Wu, Lei; Kohlmeier, Martin; Ye, Fangli; Cai, Wei

    2013-09-01

    Numerous case-control studies on the association between polymorphisms of key genes involved in methionine remethylation [methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MS)] and the susceptibility of cervical intraepithelial neoplasia (CIN) and cervical cancer have provided inconclusive results. The aim of the present meta-analysis was to determine the effects of two MTHFR (C677T and A1298C) and one MS gene polymorphism (A2756G) on the risk of CIN II/III or cervical cancer. Relevant data were retrieved following a systematic search in PubMed, Web of Science, MEDLINE and Wanfang Data up to November 2012. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were estimated from eligible studies by meta-analysis with subgroup analyses stratified by ethnicity. A total of 13 studies with 1,936 cases and 2,858 controls were included in the present meta?analysis. An increased risk of cervical cancer was found in Asian women with the MTHFR 677T allele (TT vs. CC: OR=1.41, 95% CI=1.07?1.86, P=0.01; TT vs. CC+CT: OR=1.38, 95% CI=1.08-1.75, P=0.008), while a decreased risk was observed in Caucasian women (TT vs. CC: OR=0.65, 95% CI=0.45-0.93, P=0.02; TT+CT vs. CC: OR=0.7, 95% CI=0.58-0.86, P=0.0005). No effects of MTHFR C677T polymorphism on CIN II/III risk and MTHFR A1298C or MS A2756G polymorphisms on cervical cancer risk were detected. The sensitivity analysis suggested stability of this meta-analysis and no publication bias was detected. The MTHFR 677T allele may enhance the risk of cervical cancer in the Asian female population and play a protective role in Caucasian females. However, limited association is suggested between MTHFR A1298C and MS A2756G polymorphisms with cervical tumorigenesis. PMID:23864153

  3. MTHFR-1298 A>C (rs1801131) is a predictor of survival in two cohorts of stage II/III colorectal cancer patients treated with adjuvant fluoropyrimidine chemotherapy with or without oxaliplatin.

    PubMed

    Cecchin, E; Perrone, G; Nobili, S; Polesel, J; De Mattia, E; Zanusso, C; Petreni, P; Lonardi, S; Pella, N; D'Andrea, M; Errante, D; Rizzolio, F; Mazzei, T; Landini, I; Mini, E; Toffoli, G

    2015-06-01

    Adjuvant treatment based on fluoropyrimidines (FL) improves the prognosis of stage II/III colorectal cancer (CRC). Validated predictive/prognostic biomarkers would spare therapy-related morbidity in patients with a good prognosis. We compared the impact of a set of 22 FL-related polymorphisms with the prognosis of two cohorts of CRC patients treated with adjuvant FL with or without OXA, including a total of 262 cases. 5,10-Methylentetrahydrofolate reductase (MTHFR) MTHFR-1298 A>C (rs1801131) polymorphism had a concordant effect: MTHFR-rs1801131-1298CC genotype carriers had a worse disease free survival (DFS) in both the cohorts. In the pooled population MTHFR-rs1801131-1298CC carriers had also a worse overall survival. We computed a clinical score related to DFS including MTHFR-rs1801131, tumor stage, sex and tumor location, where rs1801131 is the most detrimental factor (hazard ratio=5.3, 95% confidence interval=2.2-12.9; P-value=0.0006). MTHFR-rs1801131 is a prognostic factor that could be used as an additional criteria for the choice of the proper adjuvant regimen in stage II/III colorectal cancer patients. PMID:25331073

  4. Folate Intake and Methylenetetrahydrofolate Reductase Gene Polymorphisms as Predictive and Prognostic Biomarkers for Ovarian Cancer Risk

    PubMed Central

    Zhang, Li; Liu, Wenxin; Hao, Quan; Bao, Lewen; Wang, Ke

    2012-01-01

    Folic acid and methylenetetrahydrofolate reductase (MTHFR) may affect the development of human cancer. However, few studies have evaluated folate intake and MTHFR in susceptibility to and prognosis of patients with ovarian cancer. We conducted a prospective case-control study in 215 ovarian cancer patients and 218 controls (all Chinese) between Jan. 2004 and Jan. 2007. MTHFR C677T genotyping was done by PCR-RFLP. All patients were followed up until Dec. 2010. We found a 2.43-fold increased risk of ovarian cancer among MTHFR 677TT carriers, and a decreased risk of ovarian cancer in individuals with high folate intake (OR = 0.54, 95% CI = 0.32–0.94). Cox regression survival analysis showed that among the ovarian cancer patients, those carrying the 677TT genotype had a higher risk of death (HR = 2.17, 95% CI = 1.20–4.79), while high folate intake was associated with a lower risk of death (HR = 0.43, 95% CI = 0.33–0.88). Moreover, MTHFR 677CC carriers with higher folate intake showed a lower risk of death from ovarian cancer (HR = 0.32, 95% CI = 0.27–0.82). In summary, high folate intake may lessen susceptibility and improve the prognosis of ovarian cancer patients, while the MTHFR 677TT genotype appears to increase ovarian cancer risk and worsen its prognosis in a Chinese population. PMID:22605962

  5. Association between decreased vitamin levels and MTHFR, MTR and MTRR gene polymorphisms as determinants for elevated total homocysteine concentrations in pregnant women

    Microsoft Academic Search

    P R Barbosa; S P Stabler; A L K Machado; R C Braga; R D C Hirata; M H Hirata; L F Sampaio-Neto; R H Allen; E M Guerra-Shinohara; EM Guerra-Shinohara

    2008-01-01

    Objectives:To examine the association between methylenetetrahydrofolate reductase (MTHFR) (C677T and A1298C), methionine synthase (MTR) A2756G and methionine synthase reductase (MTRR) A66G gene polymorphisms and total homocysteine (tHcy), methylmalonic acid (MMA) and S-adenosylmethionine\\/S-adenosylhomocysteine (SAM\\/SAH) levels; and to evaluate the potential interactions with folate or cobalamin (Cbl) status.Subjects\\/Methods:Two hundred seventy-five healthy women at labor who delivered full-term normal babies. Cbl, folate, tHcy,

  6. Detection of the G34R mutation in the 5 alpha reductase 2 gene by allele specific PCR and its linkage to the 89L allele among Egyptian cases.

    PubMed

    Gad, Y Z; Khairt, R; Mazen, I; Osman, H G

    2007-01-01

    The 5 alpha-reductase type 2 deficiency is an autosomal recessive disorder of sexual development among 46,XY individuals. In Egypt, there is a prevalence of a G34R disease underlying mutation. This study aimed to devise a rapid diagnostic method based on allele specific PCR (AS-PCR) and a linked polymorphism (V89L). The results showed that one set of primers was capable to differentiate between normal, heterozygous, and affected individuals efficiently. All 34R mutation carrying sequences had 100% linkage to the 89L allele, contrasting normal ones with low 89L frequencies. This linkage infers a founder effect among Egyptians having G34R mutation. PMID:18391540

  7. MTHFR C677T polymorphism is associated with hyperlipidemia in women with polycystic ovary syndrome

    PubMed Central

    Jain, Madhu; Pandey, Priyanka; Tiwary, Narendra K; Jain, Shuchi

    2012-01-01

    CONTEXT: Women with polycystic ovary syndrome (PCOS) are prone for coronary artery disease (CAD), and hyperhomocysteinemia is an independent risk factor for CAD. MTHFR deficiency is the most common cause of hyperhomocysteinemia, thereby provoking a possible association between PCOS and MTHFR C677T polymorphism. AIMS: The aim of this study was to investigate an association of MTHFR C677T polymorphism with PCOS. SETTINGS AND DESIGN: 92 women with PCOS (Rotterdam criteria) and 95 age-matched controls were compared with respect to MTHFR C677T polymorphism. The 2 genotypes (CC and CT) obtained were compared with clinical and laboratory parameters in women with PCOS. MATERIALS AND METHODS: In a case-control study, clinical, biochemical, hormonal and genetic analysis (PCR-RFLP of peripheral leucocytes) was carried out on all women with PCOS as well as controls. STATISTICAL ANALYSIS: Student “t” test for quantitative and Chi-square test for nominal variables was used. For estimation of risk, odds ratio and 95% confidence interval were calculated. RESULTS: The odds ratio of bearing a heterozygous genotype (CT) was 1.32 in women with PCOS as compared to controls (P = 0.48). No homozygous mutation (TT) was found in the study population. Serum cholesterol was more in heterozygous (CT) genotype (215.48 ± 25.56 mg/dl) as compared to normal (CC) genotype (203.29 ± 16.35 mg/dl) in women with PCOS (P = 0.01). Similarly, serum triglyceride was more in heterozygous (CT) genotype (95.86 ± 37.34 mg/dl) as compared to normal (CC) genotype (82.36 ± 20.88 mg/dl) in women with PCOS (P = 0.04). CONCLUSIONS: Although not statistically significant, there is a slightly higher prevalence of heterozygous (CT) genotype in women with PCOS. MTHFR C677T polymorphism when present may confer an increased susceptibility to develop hyperlipidemia in women with PCOS. More prospective studies are needed to confirm whether this hyperlipidemia due to MTHFR C677T polymorphism clinically manifests into CAD in long term in women with PCOS. PMID:22870016

  8. Methylenetetrahydrofolate reductase C677T polymorphism in patients with lung cancer in a Korean population

    Microsoft Academic Search

    Lian-Hua Cui; Min-Ho Shin; Hee Nam Kim; Hye-Rim Song; Jin-Mei Piao; Sun-Seog Kweon; Jin-Su Choi; Woo-Jun Yun; Young-Chul Kim; In-Jae Oh; Kyu-Sik Kim

    2011-01-01

    Background  This study was designed to investigate an association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism\\u000a and the risk of lung cancer in a Korean population.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  We conducted a large-scale, case-control study involving 3938 patients with newly diagnosed lung cancer and 1700 healthy controls.\\u000a Genotyping was performed with peripheral blood DNA for MTHFR C677T polymorphisms. Statistical significance was estimated by\\u000a logistic regression

  9. The Association of Methylenetetrahydrofolate Reductase Genotypes with the Risk of Childhood Leukemia in Taiwan

    PubMed Central

    Chang, Wen-Shin; Ji, Hong-Xue; Hsiao, Chieh-Lun; Miao, Chia-En; Hsu, Yuan-Nian; Bau, Da-Tian

    2015-01-01

    Background Acute lymphoblastic leukemia (ALL) is the most prevalent type of pediatric cancer, the causes of which are likely to involve an interaction between genetic and environmental factors. To evaluate the effects of the genotypic polymorphisms in methylenetetrahydrofolate reductase (MTHFR) on childhood ALL risk in Taiwan, two well-known polymorphic genotypes of MTHFR, C677T (rs1801133) and A1298C (rs1801131), were analyzed to examine the extent of their associations with childhood ALL susceptibility and to discuss the MTHFR genotypic contribution to childhood ALL risk among different populations. Methodology/Principal Findings In total, 266 patients with childhood ALL and an equal number of non-cancer controls recruited were genotyped utilizing PCR-RFLP methodology. The MTHFR C677T genotype, but not the A1298C, was differently distributed between childhood ALL and control groups. The CT and TT of MTHFR C677T genotypes were significantly more frequently found in controls than in childhood ALL patients (odds ratios=0.60 and 0.48, 95% confidence intervals=0.42–0.87 and 0.24–0.97, respectively). As for gender, the boys carrying the MTHFR C677T CT or TT genotype conferred a lower odds ratio of 0.51 (95% confidence interval=0.32–0.81, P=0.0113) for childhood ALL. As for age, those equal to or greater than 3.5 years of age at onset of disease carrying the MTHFR C677T CT or TT genotype were of lower risk (odds ratio= 0.43 and 95% confidence interval=0.26–0.71, P=0.0016). Conclusions Our results indicated that the MTHFR C677T T allele was a protective biomarker for childhood ALL in Taiwan, and the association was more significant in male patients and in patients 3.5 years of age or older at onset of disease. PMID:25793509

  10. Sodium arsenite alters cell cycle and MTHFR, MT1/2, and c-Myc protein levels in MCF-7 cells

    SciTech Connect

    Ruiz-Ramos, Ruben [Centro de Investigacion en Salud Poblacional, INSP, Cuernavaca, Morelos (Mexico); Departamento de Toxicologia, Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional, 07360 Mexico D.F. (Mexico); Lopez-Carrillo, Lizbeth [Centro de Investigacion en Salud Poblacional, INSP, Cuernavaca, Morelos (Mexico); Albores, Arnulfo [Departamento de Toxicologia, Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional, 07360 Mexico D.F. (Mexico); Hernandez-Ramirez, Raul U. [Centro de Investigacion en Salud Poblacional, INSP, Cuernavaca, Morelos (Mexico); Cebrian, Mariano E., E-mail: mcebrian@cinvestav.m [Departamento de Toxicologia, Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional, 07360 Mexico D.F. (Mexico)

    2009-12-15

    There is limited available information on the effects of arsenic on enzymes participating in the folate cycle. Therefore, our aim was to evaluate the effects of sodium arsenite on the protein levels of methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase (DHFR) and its further relationship with the expression MT1/2 and c-myc in MCF-7 cells. Arsenite treatment (0-10 muM) for 4 h decreased MTHFR levels in a concentration-dependent fashion without significant effects on DHFR. The effects on MTHFR were observed at arsenite concentrations not significantly affecting cell viability. We also observed an increase in S-phase recruitment at all concentrations probed. Lower concentrations (< 5 muM) induced cell proliferation, showing a high proportion of BrdU-stained cells, indicating a higher DNA synthesis rate. However, higher concentrations (>= 5 muM) or longer treatment periods induced apoptosis. Arsenite also induced dose-dependent increases in MT1/2 and c-Myc protein levels. The levels of MTHFR were inversely correlated to MT1/2 and c-Myc overexpression and increased S-phase recruitment. Our findings indicate that breast epithelial cells are responsive to arsenite and suggest that exposure may pose a risk for breast cancer. The reductions in MTHFR protein levels contribute to understand the mechanisms underlying the induction of genes influencing growth regulation, such as c-myc and MT1/2. However, further research is needed to ascertain if the effects here reported following short-time and high-dose exposure are relevant for human populations chronically exposed to low arsenic concentrations.

  11. Alteration of the alkaloid profile in genetically modified tobacco reveals a role of methylenetetrahydrofolate reductase in nicotine N-demethylation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme of the tetrahydrofolate (THF)-mediated one-carbon (C1) metabolic network. This enzyme catalyzes reduction of 5,10-methylene-THF to 5-methyl-THF. The latter donates its methyl group to homocysteine forming Met, which is then used for the syn...

  12. Gene-environment and gene-gene interactions of specific MTHFR, MTR and CBS gene variants in relation to homocysteine in black South Africans.

    PubMed

    Nienaber-Rousseau, Cornelie; Ellis, Suria M; Moss, Sarah J; Melse-Boonstra, Alida; Towers, G Wayne

    2013-11-01

    The methylenetetrahydrofolate reductase (MTHFR), cystathione-?-synthase (CBS) and methionine synthase (MTR) genes interact with each other and the environment. These interactions could influence homocysteine (Hcy) and diseases contingent thereon. We determined single nucleotide polymorphisms (SNPs) within these genes, their relationships and interactions with total Hcy concentrations within black South Africans to address the increased prevalence of diseases associated with Hcy. The MTHFR 677 TT and MTR 2756 AA genotypes were associated with higher Hcy concentrations (16.6 and 10.1 ?mol/L; p<0.05) compared to subjects harboring the MTHFR 677 CT/CC and the MTR 2756 AG genotypes (10.5, 9.7 and 9.5 ?mol/L, respectively). The investigated CBS genotypes did not influence Hcy. We demonstrated interactions between the area of residence and the CBS T833C/844ins68 genotypes (p=0.005) so that when harboring the wildtype allele, rural subjects had significantly higher Hcy than their urban counterparts, but when hosting the variant allele the environment made no difference to Hcy. Between the CBS T833C/844ins68 or G9276A and MTHFR C677T genotypes, there were two-way interactions (p=0.003 and=0.004, respectively), with regard to Hcy. Subjects harboring the MTHFR 677 TT genotype in combination with the CBS 833 TT/homozygous 844 non-insert or the MTHFR 677 TT genotype in combination with the CBS 9276 GA/GG displayed higher Hcy concentrations. Therefore, some of the investigated genotypes affected Hcy; residential area changed the way in which the CBS T833C/844ins68 SNPs influenced Hcy concentrations highlighting the importance of environmental factors; and gene-gene interactions allude to epistatic effects. PMID:23954866

  13. Hyperhomocyst(e)inemia and MTHFR C677T genotypes in patients with central retinal vein occlusion

    Microsoft Academic Search

    Martin Weger; Olaf Stanger; Hannes Deutschmann; Werner Temmel; Wilfried Renner; Otto Schmut; Jürgen Semmelrock; Anton Haas

    2002-01-01

    Background: Elevated plasma homocyst(e)ine is a major risk factor for venous thrombosis and cardiovascular disease. Homozygosity for the MTHFR C677T mutation and low plasma folate levels increase plasma homocyst(e)ine concentrations. The aim of this retrospective case-control study was to investigate a possible association between hyperhomocyst(e)inemia and central retinal vein occlusion. Methods: Our study included 78 consecutive patients with central retinal

  14. Copper-containing nitrite reductase from Pseudomonas aureofaciens is functional in a mutationally cytochrome cd 1 -free background (NirS ? ) of Pseudomonas stutzeri

    Microsoft Academic Search

    Andrea B. Glockner; Angelika Jiingst; Walter G. Zumft

    1993-01-01

    The structural gene, nirK, for the respiratory Cu-containing nitrite reductase from denitrifying Pseudomonas aureofaciens was isolated and sequenced. It encodes a polypeptide of 363 amino acids including a signal peptide of 24 amino acids for protein export. The sequence showed 63.8% positional identity with the amino acid sequence of “Achromobacter cycloclastes” nitrite reductase. Ligands for the blue, type I Cu-binding

  15. Folate intake and MTHFR polymorphism C677T is not associated with ovarian cancer risk: evidence from the meta-analysis.

    PubMed

    Li, Chenglin; Chen, Peizhan; Hu, Pingting; Li, Mian; Li, Xiaoguang; Guo, He; Li, Jingquan; Chu, Ruiai; Zhang, Wei; Wang, Hui

    2013-12-01

    Folate is essential for DNA synthesis and methylation and implicated in the process of carcinogenesis. Several studies inconclusively suggested increased folate intake may reduce ovarian cancer risk. Studies concerning the association between C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR), an important enzyme in folate metabolism, and ovarian cancer risk also resulted in no agreement. The meta-analysis was conducted based on current studies to assess the association between folate intake, the MTHFR C667T polymorphism and ovarian cancer risk. 1,158 cases out of 217,309 participants from four cohort studies, 4,519 cases and 6,031 controls from four case-control studies about folate intake along with 5,617 cases and 9,808 controls from 10 publications concerning the polymorphism were pooled, respectively. We detected no significant association between total folate (RR = 1.04, 95 % confidence interval (CI) = 0.87-1.23) or dietary folate (RR = 0.88, 95 % CI = 0.75-1.05) intake and ovarian cancer risk, and also no significant relationship was found between MTHFR C677T polymorphism and ovarian cancer risk (TT vs. CC: odds ratio (OR) = 1.15, 95 % CI = 0.90-1.46; CT vs. CC: OR = 1.04, 95 % CI = 0.94-1.16). Our analysis indicated neither folate intake nor MTHFR C677T polymorphism is related to altered susceptibility of ovarian cancer. PMID:24129496

  16. Association between MTHFR C677T Polymorphism and Risk of Acute Lymphoblastic Leukemia: A Meta-Analysis Based on 51 Case-Control Studies

    PubMed Central

    Li, Su-yi; Ye, Jie-yu; Liang, En-yu; Zhou, Li-xia; Yang, Mo

    2015-01-01

    Background Studies and systematic reviews have reached inconsistent conclusions on the role of 5, 10-methylenetetrahydrofolate reductase (MTHFR) polymorphism C677T in acute lymphoblastic leukemia (ALL) risk. Material/Methods The present meta-analysis comprising of 51 case-control studies, including 7892 cases and 14 280 controls was performed to reevaluate the association between MTHFR C677T polymorphism and ALL risk. Results Statistical differences were found in the dominant model (TT+CT vs. CC, odd ratio (OR)=0.89, 95% CI, 0.79–1.00, P=0.04) and the CT vs. CC (OR=0.89, 95% CI, 0.80–1.00, P=0.05), but not in the allele contrast model (T vs. C, OR=0.92, 95% CI, 0.84–1.01, P=0.08), additive model (TT vs. CC, OR=0.87, 95% CI, 0.73–1.05, P=0.15), or recessive model (TT vs. CT+CC, OR=0.94, 95% CI, 0.81–1.10, P=0.44) in overall populations. In the subgroup analyses stratified by age (children and adults) and ethnicity (Asian and Caucasian), no significant associations between MTHFR C677T polymorphism and ALL risk were observed. Conclusions The current study found no sufficient evidence of a protective role of MTHFR C677T polymorphism in ALL susceptibility. PMID:25761797

  17. MTHFR A1298C and C677T gene polymorphisms and susceptibility to chronic myeloid leukemia in Egypt

    PubMed Central

    Aly, Rabab M; Taalab, Mona M; Ghazy, Hayam F

    2014-01-01

    Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme regulating the intracellular folate metabolism which plays an important role in carcinogenesis through DNA methylation. We aimed to evaluate the association between MTHFR A1298C and C677T polymorphisms and the risks of chronic myeloid leukemia (CML). Eighty-five patients with CML and a control group containing 100 healthy, age and sex matched individuals were examined for MTHFR C677T and A1298C polymorphisms using polymerase chain reaction-restriction fragment-length (PCR-RFLP) method. The frequency of 677TT genotype in patients with CML was significantly higher compared to controls (OR = 2.513, 95% CI: 0.722-4.086, P = 0.025). No such association was shown for heterozygous 677CT (OR = 1.010, 95% CI: 0.460-2.218, P = 0.981). Moreover, for A1298C genotype, a statistically significant higher frequency of 1298CC was also detected in CML patients compared to control group (OR = 1.1816, 95% CI: 0.952-3.573, P = 0.036), 0.036). No such statistical significance was demonstrable for heterozygote 1298AC (OR = 1.046, 95% CI: 0.740-1.759, P = 0.092). In addition, patients with joint 677CT/1298AC or 677TT/1298CC genotypes showed an association with increased risk of CML (OR = 1.849, 95% CI: 0.935-2.540, P = 0.024; OR = 1.915, 95% CI: 1.202-3.845, P = 0.020 respectively). .A statistically significant increased risk of resistant to therapy was observed with 677CT and 1298AC genotypes (P = 0.001, P = 0.002 respectively). We conclude that both MTHFR 677TT and 1298CC polymorphisms have been associated with risk of CML and both 677CT and 1298AC genotypes are associated with higher risk of resistant to therapy. PMID:24966971

  18. Alteration of the Alkaloid Profile in Genetically Modified Tobacco Reveals a Role of Methylenetetrahydrofolate Reductase in Nicotine N-Demethylation1[C][W][OA

    PubMed Central

    Hung, Chiu-Yueh; Fan, Longjiang; Kittur, Farooqahmed S.; Sun, Kehan; Qiu, Jie; Tang, She; Holliday, Bronwyn M.; Xiao, Bingguang; Burkey, Kent O.; Bush, Lowell P.; Conkling, Mark A.; Roje, Sanja; Xie, Jiahua

    2013-01-01

    Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme of the tetrahydrofolate (THF)-mediated one-carbon (C1) metabolic network. This enzyme catalyzes the reduction of 5,10-methylene-THF to 5-methyl-THF. The latter donates its methyl group to homocysteine, forming methionine, which is then used for the synthesis of S-adenosyl-methionine, a universal methyl donor for numerous methylation reactions, to produce primary and secondary metabolites. Here, we demonstrate that manipulating tobacco (Nicotiana tabacum) MTHFR gene (NtMTHFR1) expression dramatically alters the alkaloid profile in transgenic tobacco plants by negatively regulating the expression of a secondary metabolic pathway nicotine N-demethylase gene, CYP82E4. Quantitative real-time polymerase chain reaction and alkaloid analyses revealed that reducing NtMTHFR expression by RNA interference dramatically induced CYP82E4 expression, resulting in higher nicotine-to-nornicotine conversion rates. Conversely, overexpressing NtMTHFR1 suppressed CYP82E4 expression, leading to lower nicotine-to-nornicotine conversion rates. However, the reduced expression of NtMTHFR did not affect the methionine and S-adenosyl-methionine levels in the knockdown lines. Our finding reveals a new regulatory role of NtMTHFR1 in nicotine N-demethylation and suggests that the negative regulation of CYP82E4 expression may serve to recruit methyl groups from nicotine into the C1 pool under C1-deficient conditions. PMID:23221678

  19. Methylenetetrahydrofolate reductase C677T and overall survival in pediatric acute lymphoblastic leukemia: a systematic review.

    PubMed

    Ojha, Rohit P; Gurney, James G

    2014-01-01

    A summary of the evidence pertaining to the association between methylenetetrahydrofolate reductase (MTHFR) C677T and overall survival in pediatric acute lymphoblastic leukemia (ALL) is not currently available. We thus reviewed the literature on the association between MTFHR C677T and overall survival in pediatric ALL. We searched PubMed/MEDLINE, Scopus and ISI Web of Knowledge literature databases without language restrictions to identify observational studies among children diagnosed between ages 0 and 19 years that assessed MTHFR 677 polymorphisms in relation to ALL survival. We identified six studies comprising 909 pediatric patients with ALL. The magnitude of relative risk (RR) for pediatric ALL mortality varied by genotype comparison and study population, ranging from RR = 0.84 (95% confidence limits [CL]: 0.24, 3.0) for a TT vs. CT/CC comparison to RR = 7.0 (95% CL: 0.98, 49) for a TT vs. CC comparison. The current evidence suggests that individuals with MTHFR 677 variants (i.e. at least one T allele) may have a higher relative risk of pediatric ALL mortality, with greater statistical support for MTHFR 677TT. With more detailed supporting evidence, MTHFR 677 genotyping at diagnosis could provide an option for individualizing therapy and further reducing pediatric ALL mortality in certain populations. PMID:23550988

  20. Methylenetetrahydrofolate reductase C677T and methionine synthase A2756G polymorphisms influence on leukocyte genomic DNA methylation level.

    PubMed

    Weiner, Alexandra S; Boyarskikh, Uljana A; Voronina, Elena N; Mishukova, Olga V; Filipenko, Maxim L

    2014-01-01

    Methionine synthase (MTR) and methylenetetrahydrofolate reductase (MTHFR) enzymes are involved in the metabolism of methyl groups, and thus have an important role in the maintenance of proper DNA methylation level. In our study we aimed to evaluate the effect of the polymorphism A2756G (rs1805087) in the MTR gene on the level of human leukocyte genomic DNA methylation. Since the well-studied polymorphism C677T (rs1801133) in the MTHFR gene has already been shown to affect DNA methylation, we aimed to analyze the effect of MTR A2756G independently of the MTHFR C677T polymorphism. For this purpose, we collected the groups of 80 subjects with the MTR 2756AA genotype and 80 subjects with the MTR 2756GG genotype, having equal numbers of individuals with the MTHFR 677CC and the MTHFR 677TT genotypes, and determined the level of DNA methylation in each group. Individuals homozygous for the mutant MTR 2756G allele showed higher DNA methylation level than those harboring the MTR 2756AA genotype (5.061 ± 1.761% vs. 4.501 ± 1.621%, P=0.0391). Individuals with wild-type MTHFR 677?C genotype displayed higher DNA methylation level than the subjects with mutant MTHFR 677TT genotype (5.103 ± 1.767% vs. 4.323 ± 1.525%, P=0.0034). Our data provide evidence that the MTR A2756G polymorphism increases the level of DNA methylation and confirm the previous reports that the MTHFR C677T polymorphism is associated with DNA hypomethylation. PMID:24103477

  1. Folate/homocysteine phenotypes and MTHFR 677C>T genotypes are associated with serum levels of monocyte chemoattractant protein-1

    PubMed Central

    Hammons, Andrea L.; Summers, Carolyn M.; Woodside, Jayne V.; McNulty, Helene; Strain, J.J.; Young, Ian S.; Murray, Liam; Boreham, Colin A.; Scott, John M.; Mitchell, Laura E.; Whitehead, Alexander S.

    2014-01-01

    Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that recruits monocytes into the subendothelial cell layer in atherosclerotic lesions. Elevated homocysteine (hyper-homocysteinemia), which is usually associated with low-folate status, is a known risk factor for many pathologies with inflammatory etiologies. The present study was undertaken to examine whether there are associations between MCP-1 concentrations and folate/Hcy phenotype or methylenetetrahydrofolate reductase (MTHFR) 677C>T genotype in healthy young adults. In females, MCP-1 concentrations were positively correlated with Hcy and negatively correlated with both serum and red blood cell folate; female smokers and MTHFR 677T carriers had particularly elevated MCP-1 concentrations. Similar relationships were not seen in males. These findings may have implications for understanding the female predominance observed for a range of autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis. PMID:19625220

  2. Folate/homocysteine phenotypes and MTHFR 677C>T genotypes are associated with serum levels of monocyte chemoattractant protein-1.

    PubMed

    Hammons, Andrea L; Summers, Carolyn M; Woodside, Jayne V; McNulty, Helene; Strain, J J; Young, Ian S; Murray, Liam; Boreham, Colin A; Scott, John M; Mitchell, Laura E; Whitehead, Alexander S

    2009-10-01

    Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that recruits monocytes into the subendothelial cell layer in atherosclerotic lesions. Elevated homocysteine (hyperhomocysteinemia), which is usually associated with low-folate status, is a known risk factor for many pathologies with inflammatory etiologies. The present study was undertaken to examine whether there are associations between MCP-1 concentrations and folate/Hcy phenotype or methylenetetrahydrofolate reductase (MTHFR) 677C>T genotype in healthy young adults. In females, MCP-1 concentrations were positively correlated with Hcy and negatively correlated with both serum and red blood cell folate; female smokers and MTHFR 677T carriers had particularly elevated MCP-1 concentrations. Similar relationships were not seen in males. These findings may have implications for understanding the female predominance observed for a range of autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis. PMID:19625220

  3. Effect of the Methylenetetrahydrofolate Reductase C677T Polymorphism on Chemosensitivity of Colon and Breast Cancer Cells to 5Fluorouracil and Methotrexate

    Microsoft Academic Search

    Kyoung-Jin Sohn; Ruth Croxford; Zoe Yates; Mark Lucock; Young-In Kim

    Background: Although single nucleotide polymorphisms may be potentially important pharmacogenetic determi- nants of cancer therapy, functional evidence regarding their relevance is currently lacking. The C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with changes in cellular composition of folates. We hypothesized that this polymorphism may modulate the cytotoxic effect of 5-fluorouracil (5FU) and methotrexate (MTX), two commonly used

  4. Altered Folate Metabolism and Disposition in Mothers Affected by a Spina Bifida Pregnancy: Influence of 677c ? t Methylenetetrahydrofolate Reductase and 2756a ? g Methionine Synthase Genotypes

    Microsoft Academic Search

    Mark Lucock; Ioannis Daskalakis; David Briggs; Zoe Yates; Malcolm Levene

    2000-01-01

    Periconceptional folate prevents spina bifida although the mechanisms involved are unclear. We present the genotype frequency for the 677 ct methylenetetrahydrofolate reductase (MTHFR) and 2756ag methionine synthase (MetSyn) polymorphisms. Calculated odds ratios (OR) show that neither the homozygous recessive genotype, carriage of the mutant allele, nor frequency of the mutant allele represent significantly increased risk for neural tube defect (NTD).

  5. Meta-analyses of Blood Homocysteine Levels for Gender and Genetic Association Studies of the MTHFR C677T Polymorphism in Schizophrenia

    PubMed Central

    Nishi, Akira; Numata, Shusuke; Tajima, Atsushi; Kinoshita, Makoto; Kikuchi, Kumiko; Shimodera, Shinji; Tomotake, Masahito; Ohi, Kazutaka; Hashimoto, Ryota; Imoto, Issei; Takeda, Masatoshi; Ohmori, Tetsuro

    2014-01-01

    Previous studies suggest that elevated blood homocysteine levels and the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism are risk factors for schizophrenia. However, the effects of gender and MTHFR C677T genotypes on blood homocysteine levels in schizophrenia have not been consistent. We first investigated whether plasma total homocysteine levels were higher in patients with schizophrenia than in controls with stratification by gender and by the MTHFR C677T genotypes in a large cohort (N = 1379). Second, we conducted a meta-analysis of association studies between blood homocysteine levels and schizophrenia separately by gender (N = 4714). Third, we performed a case-control association study between the MTHFR C677T polymorphism and schizophrenia (N = 4998) and conducted a meta-analysis of genetic association studies based on Japanese subjects (N = 10 378). Finally, we assessed the effect of plasma total homocysteine levels on schizophrenia by a mendelian randomization approach. The ANCOVA after adjustment for age demonstrated a significant effect of diagnosis on the plasma total homocysteine levels in all strata, and the subsequent meta-analysis for gender demonstrated elevated blood homocysteine levels in both male and female patients with schizophrenia although antipsychotic medication might influence the outcome. The meta-analysis of the Japanese genetic association studies demonstrated a significant association between the MTHFR C677T polymorphism and schizophrenia. The mendelian randomization analysis in the Japanese populations yielded an OR of 1.15 for schizophrenia per 1-SD increase in plasma total homocysteine. Our study suggests that increased plasma total homocysteine levels may be associated with an increased risk of schizophrenia. PMID:24535549

  6. Antisense modulation of 5,10-methylenetetrahydrofolate reductase expression produces neural tube defects in mouse embryos

    Microsoft Academic Search

    Deborah K. Hansen; Scott A. Barbee; Thomas F. Grafton; Yan Gu; Randal D. Streck

    2000-01-01

    The role of folate metabolism in producing neural tube defects (NTDs) in humans is unknown. In the current study, antisense oligodeoxyribonucleotide technology was utilized to disrupt normal expression of the gene for 5,10-methylenetetrahydrofolate reductase (MTHFR) in organogenesis-stage mouse embryos. Two different antisense probes were microinjected into the amniotic sac of gestation day (GD) 8 mouse embryos with PBS or scrambled

  7. Maternal Vitamin Use, Genetic Variation of Infant Methylenetetrahydrofolate Reductase, and Risk for Spina Bifida

    Microsoft Academic Search

    Gary M. Shaw; Rima Rozen; Richard H. Finnell; Cathy R. Wasserman; Edward J. Lammer

    Maternal periconceptional use of vitamin supplements containing folic acid substantially reduces the risk of neural tube defects (NTDs) in the offspring. The mechanism underlying this reduction in risk is unknown. Several recent studies have reported an association between homozygosity for a variant form (the C677T genotype) of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene and risk for NTDs in individuals. It has

  8. Characterization and site-directed mutation of a novel aldo-keto reductase from Lodderomyces elongisporus NRRL YB-4239 with high production rate of ethyl (R)-4-chloro-3-hydroxybutanoate.

    PubMed

    Wang, Qiuyan; Ye, Tingting; Ma, Zhuanzhuan; Chen, Rong; Xie, Tian; Yin, Xiaopu

    2014-11-01

    A novel aldo-keto reductase (LEK) from Lodderomyces elongisporus NRRL YB-4239 (ATCC 11503) was discovered by genome database mining for carbonyl reduction. LEK was overexpressed in Escherichia coli BL21 (DE3), purified to homogeneity and the catalytic properties were studied. Among the substrates, ethyl 4-chloro-3-oxobutanoate was converted to ethyl (R)-4-chloro-3- hydroxybutanoate ((R)-CHBE), an important pharmaceutical intermediate, with an excellent enantiomeric excess (e.e.) (>99 %). The mutants W28A and S209G obtained by site-directed mutation were identified with much higher molar conversion yields and lower Km values. Further, the constructed coenzyme regeneration system with glucose as co-substrate resulted in a yield of 100 %, an enantioselectivity of >99 %, and the calculated production rate of 56.51 mmol/L/H. These results indicated the potential of LEK for the industrial production of (R)-CHBE and other valuable chiral alcohols. PMID:25189809

  9. Influence of the cystathionine ?-synthase 844ins68 and methylenetetrahydrofolate reductase 677C>T polymorphisms on folate and homocysteine concentrations

    PubMed Central

    Summers, Carolyn M; Hammons, Andrea L; Mitchell, Laura E; Woodside, Jayne V; Yarnell, John WG; Young, Ian S; Evans, Alun; Whitehead, Alexander S

    2014-01-01

    A high homocysteine, low folate phenotype is a feature of many diseases. The effect of the cystathionine ?-synthase (CBS) 844ins68 polymorphism on homocysteine and folate concentrations was examined alone and in the context of the 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism in a Northwestern European male population. The MTHFR 677TT genotype is known to be associated with increased homocysteine and decreased folate relative to CT heterozygotes and CC homozygotes in this and other populations. MTHFR 677TT homozygotes who were also CBS 844ins68 carriers had homocysteine and folate concentrations similar to those of individuals with the MTHFR 677CT and CC genotypes. Homocysteine levels in MTHFR 677TT subjects carrying the CBS 844ins68 allele were 24.1% lower than in non-carriers (6.66 vs 8.77 ?mol/l, P=0.045), and serum folate levels were 27.7% higher (11.16 vs 8.74 nmol/l, P=0.034). These findings suggest that the CBS 844ins68 allele ‘normalizes’ homocysteine and folate levels in MTHFR 677TT individuals. PMID:18398434

  10. Influence of the cystathionine beta-synthase 844ins68 and methylenetetrahydrofolate reductase 677C>T polymorphisms on folate and homocysteine concentrations.

    PubMed

    Summers, Carolyn M; Hammons, Andrea L; Mitchell, Laura E; Woodside, Jayne V; Yarnell, John W G; Young, Ian S; Evans, Alun; Whitehead, Alexander S

    2008-08-01

    A high homocysteine, low folate phenotype is a feature of many diseases. The effect of the cystathionine beta-synthase (CBS) 844ins68 polymorphism on homocysteine and folate concentrations was examined alone and in the context of the 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism in a Northwestern European male population. The MTHFR 677TT genotype is known to be associated with increased homocysteine and decreased folate relative to CT heterozygotes and CC homozygotes in this and other populations. MTHFR 677TT homozygotes who were also CBS 844ins68 carriers had homocysteine and folate concentrations similar to those of individuals with the MTHFR 677CT and CC genotypes. Homocysteine levels in MTHFR 677TT subjects carrying the CBS 844ins68 allele were 24.1% lower than in non-carriers (6.66 vs 8.77 micromol/l, P=0.045), and serum folate levels were 27.7% higher (11.16 vs 8.74 nmol/l, P=0.034). These findings suggest that the CBS 844ins68 allele 'normalizes' homocysteine and folate levels in MTHFR 677TT individuals. PMID:18398434

  11. 5,10-Methylenetetrahydrofolate reductase single nucleotide polymorphisms and gene-environment interaction analysis in non-syndromic cleft lip/palate.

    PubMed

    Estandia-Ortega, Bernardette; Velázquez-Aragón, José A; Alcántara-Ortigoza, Miguel A; Reyna-Fabian, Miriam E; Villagómez-Martínez, Sandra; González-Del Angel, Ariadna

    2014-04-01

    Non-syndromic cleft lip/palate (NSCL/P) is a common congenital defect in Mexico. Periconceptional intake of folic acid (FA) may reduce the risk of this malformation. Although the 5,10-methylenetetrahydrofolate reductase (MTHFR) enzyme participates in folate metabolism, several studies failed to find any association between NSCL/P and the MTHFR C677T and A1298C polymorphisms. However, interactions among NSCL/P, MTHFR gene polymorphisms, and FA intake have not been explored in Mexican populations. This case-control study included 132 patients with NSCL/P and 370 controls from Mexico City. Maternal FA consumption during pregnancy was examined, as were the MTHFR C677T and A1298C polymorphisms and gene-FA interactions. Maternal FA intake during the periconceptional period was lower in cases (1.5%) than in controls (13%), with the risk of delivering a child with NSCL/P lower in mothers who consumed FA (OR = 0.29, 95% CI: 0.19-0.44). In addition, the risk of NSCL/P was lower in children with the TT than the CC genotype of MTHFR C677T (OR = 0.39, 95% CI: 0.23-0.68), after Bonferroni correction and exclusion of stratification. No evidence of gene-FA interaction was found. These results indicate that maternal FA intake and the TT genotype of the MTHFR C677T polymorphism in children independently reduced the risk of NSCL/P in our population. PMID:24460828

  12. Methylenetetrahydrofolate reductase gene polymorphisms and the risk of anencephaly in Mexico

    Microsoft Academic Search

    Julia Blanco Munoz; Marina Lacasana; R. G. Cavazos; Victor Hugo Borja-Aburto; C. Galaviz-Hernandez; Clemente Aguilar Garduno

    2007-01-01

    The precise etiology of neural tube defects (NTDs) is not known. There is some evidence that mutations in MTHFR gene provide susceptibility to NTDs in some populations; however, other studies have not found this association. One of the problems with pre- vious studies is that they treat NTDs as a homogeneous group, when specific defects could have different etiologies. We

  13. Association between polymorphisms in genes encoding methylenetetrahydrofolate reductase and the risk of Ménière's disease.

    PubMed

    Huang, Yang; Teranishi, Masaaki; Uchida, Yasue; Nishio, Naoki; Kato, Ken; Otake, Hironao; Yoshida, Tadao; Sone, Michihiko; Sugiura, Saiko; Ando, Fujiko; Shimokata, Hiroshi; Nakashima, Tsutomu

    2013-06-01

    Folate metabolism is essential for cellular functioning. Despite extensive research on the roles of folate-metabolism-related gene polymorphisms in the pathophysiology of many diseases, such as cardiovascular disease, cancers, and sudden sensorineural hearing loss, little is known about their association with Ménière's disease (MD). The aim of this study was to investigate the effect of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms (C677T and A1298C) on the risk of MD in a Japanese population. We examined the C677T and A1298C (rs1801133 and rs1801131) polymorphisms in the MTHFR gene and compared them between 1946 adults (986 men and 960 women) participating in the National Institute for Longevity Sciences Longitudinal Study of Aging and 86 cases of MD. A multiple logistic regression was performed to obtain odds ratios (ORs) for the risk of MD regarding the MTHFR polymorphisms before (model 1) and after (model 2) adjustment for age and sex factors. The OR of MTHFR C677T for the risk of MD was 0.669 (95% confidence interval [CI], 0.479-0.934) in model 1 and 0.680 (95% CI, 0.484-0.954) in model 2. In contrast, the OR of MTHFR A1298C for the risk of MD was 1.503 (95% CI, 1.064-2.123) in model 1 and 1.505 (95% CI, 1.045-2.167) in model 2. Our results imply that the MTHFR C677T and A1298C polymorphisms are associated with the risk of MD. PMID:23484733

  14. Effects of methionine synthase and methylenetetrahydrofolate reductase gene polymorphisms on markers of one-carbon metabolism.

    PubMed

    Ho, Vikki; Massey, Thomas E; King, Will D

    2013-11-01

    Genetic and nutritional factors play a role in determining the functionality of the one-carbon (1C) metabolism cycle, a network of biochemical reactions critical to intracellular processes. Genes encoding enzymes for methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR) may determine biomarkers of the cycle including homocysteine (HCY), S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH). MTHFR C677T is an established genetic determinant of HCY but less is known of its effect on SAM and SAH. Conversely, the relationship between MTR A2756G and HCY remains inconclusive, and its effect on SAM and SAH has only been previously investigated in a female-specific population. Folate and vitamin B12 are essential substrate and cofactor of 1C metabolism; thus, consideration of gene-nutrient interactions may clarify the role of genetic determinants of HCY, SAM and SAH. This cross-sectional study included 570 healthy volunteers from Kingston, Ontario, Ottawa, Ontario and Halifax, Nova Scotia, Canada. Least squares regression was used to examine the effects of MTR and MTHFR polymorphisms on plasma HCY, SAM and SAH concentrations; gene-gene and gene-nutrient interactions were considered with the inclusion of cross-products in the model. Main effects of MTR and MTHFR polymorphisms on HCY concentrations were observed; however, no gene-gene or gene-nutrient interactions were found. No association was observed for SAM. For SAH, interactions between MTR and MTHFR polymorphisms, and MTHFR polymorphism and serum folate were found. The findings of this research provide evidence that HCY and SAH, biomarkers of 1C metabolism, are influenced by genetic and nutritional factors and their interactions. PMID:24101362

  15. Laboratory informatics based evaluation of methylene tetrahydrofolate reductase C677T genetic test overutilization

    PubMed Central

    Cohen, David A.; Shirts, Brian H.; Jackson, Brian R.; Parker, Lisa S.

    2013-01-01

    Background: Laboratory data can provide a wide range of information to estimate adherence to guidelines and proper utilization of genetic testing. The methylene tetrahydrofolate reductase (MTHFR) C677T variant has been demonstrated to have negligible utility in patient management. However, the testing of this variant remains pervasive. The purpose of this study was to develop methods to analyze concordance of clinician ordering practices with national guidelines. Methods: We used laboratory data to extract specific data elements including patient demographics, timestamps, physician ordering logs and temporal relationship to chemistry requests to examine 245 consecutive MTHFR tests ordered in 2011 at an academic tertiary center. A comprehensive chart review was used to identify indications for testing. These results were correlated with a retrospective analysis of 4,226 tests drawn at a range of hospitals requesting testing from a national reference laboratory over a 2-year period. MTHFR ordering practices drawn from 17 institutions were examined longitudinally from 2002 to 2011. Results: Indications for testing included cerebrovascular events (40.0%) and venous thrombosis (39.1%). Family history prompted testing in eight cases. Based on acceptable hypercoagulability guidelines recommending MTHFR C677T testing only in the presence of elevated serum homocysteine, 10.6% (22/207) of adult patients met an indicated threshold at an academic tertiary center. Among 77 institutions, 14.5% (613/4226) of MTHFR testing met recommendations. Conclusion: We demonstrate an effective method to examine discreet elements of a molecular diagnostics laboratory information system at a tertiary care institution and to correlate these findings at a national level. Retrospective examination of clinicians’ request of MTHFR C677T genetic testing strongly suggests that clinicians have failed to adjust their ordering practices in light of evolving scientific and professional organization recommendations. PMID:24392247

  16. MTHFR polymorphisms in Puerto Rican children with isolated congenital heart disease and their mothers

    PubMed Central

    García-Fragoso, Lourdes; García-García, Inés; Leavitt, Gloria; Renta, Jessicca; Ayala, Miguel A.; Cadilla, Carmen L.

    2010-01-01

    Congenital heart defects (CHD) are among the most common birth defects. There is evidence suggesting that polymorphisms in folate metabolism could alter susceptibility to CHD. The MTHFR 677TT genotype has been associated with the development of structural congenital heart malformations. The objective of this study was to identify common polymorphisms in the MTHFR gene in children with isolated CHD and their mothers. The DNA analysis for the C677T and A1298C mutations was performed. The study group included 27 mothers, 27 children with CHD, and 220 controls. The prevalence of the TT polymorphism was higher in mothers (22%) than in controls (10%). Compound heterozygosity for both polymorphisms was 3.7 times more common in children with CHD than in the newborn controls. Mothers of children with CHD were more likely to be compound heterozygotes. The higher prevalence of C677T polymorphisms in mothers of children with CHD and of compound heterozygosity for both polymorphisms suggests the possible role of folic acid in the prevention of CHD. Due to the relation of this enzyme to folate metabolism, current folate recommendations for women in childbearing age in Puerto Rico to reduce neural tube defects may need to be extended to the prevention of CHD. PMID:20657745

  17. MTHFR C677T polymorphism and recurrent early pregnancy loss risk in north Indian population.

    PubMed

    Nair, Rohini R; Khanna, Anuradha; Singh, Kiran

    2012-02-01

    Recurrent early pregnancy loss (REPL) is a multifactorial disorder as both genetic and environmental factors contribute to the development of disease. Folate metabolism is an important mechanism to ensure proper fetal growth. Hyperhomocysteinemia leads to a number of disorders and REPL is one of them. In a case-control study DNA from 106 cases with the history of 3 or more REPL and 140 healthy fertile controls with successful pregnancy outcomes were genotyped for C677T single-nucleotide polymorphism (SNP) of the MTHFR (methylenetetrahydrofolate reductase) gene through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), which was further confirmed by sequencing. Allele frequencies of REPL cases were compared with healthy controls and a statistically significant association was found between REPL and the mutant T allele (?² = 8.786, odds ratio [OR] = 2.20, 95% confidence interval [CI] = 1.323-3.9658, P = .003). The genotype frequencies of SNP C677T also differ significantly between these 2 groups (?² = 8.237, P = .016). The OR for heterozygous CT in the REPL versus controls is 1.9591 (95% CI = 1.0285-3.7318, P = .04). The OR for TT homozygous is 6.3009 (95% CI = 1.2065, P = .02). Combined odds ratio of CT and TT against the control has been calculated as 2.2194 (95% CI = 1.2029-4.0952, P = .02) which is also significant. Thus the present study clearly indicates that homozygosity and heterozygosity for the MTHFR C677T polymorphism confer a 6.3009- and 1.9591-fold increased risk of idiopathic REPL, respectively. PMID:22138544

  18. Polymorphisms in methylenetetrahydrofolate reductase gene and risk of non-Hodgkin lymphoma in a multi-ethnic population.

    PubMed

    Suthandiram, Sujatha; Gan, Gin Gin; Zain, Shamsul Mohd; Haerian, Batoul Sadat; Bee, Ping Chong; Lian, Lay Hoong; Chang, Kian Meng; Ong, Tee Chuan; Mohamed, Zahurin

    2014-05-01

    An imbalance in folate metabolism can adversely affect DNA synthesis and methylation systems which can lead to susceptibility to non-Hodgkin lymphoma (NHL). Whether single nucleotide polymorphisms (SNPs) and their haplotypes in the methylenetetrahydrofolate reductase (MTHFR) are associated with NHL, remain inconclusive. We investigated the association between MTHFR C677T and A1298C SNPs and NHL risk in a population which is made up of Malay, Chinese and Indian ethnic subgroups. A total of 372 NHL patients and 722 controls were genotyped using the Sequenom MassARRAY platform. Our results of the pooled subjects failed to demonstrate significant association between the MTHFR C677T and A1298C SNPs with NHL and its subtypes. The results were in agreement with the previous meta-analyses. In the Indian ethnic subgroup however, single locus analysis of MTHFR A1298C appears to confer risk to NHL (Odds ratio (OR) 1.91, 95% confidence interval (95% CI) 1.22-3.00, P=0.006). The risk is almost doubled in homozygous carrier of MTHFR 1298CC (OR 4.03, 95% CI 1.56-10.43, P=0.004). Haplotype analysis revealed higher frequency of CC in the Indian NHL patients compared with controls (OR 1.86, 95% CI 1.18-2.93, P=0.007). There is lack of evidence to suggest an association between MTHFR C677T and A1298C with the risk of NHL in the Malays and Chinese. In the Indians however, the MTHFR A1298C confers risk to NHL. This study suggests ethnicity modifies the relationship between polymorphisms in the folate-metabolizing gene and NHL. PMID:24646728

  19. Methylenetetrahydrofolate reductase C677T variant in Indian children with craniosynostosis: Its role in the pathogenesis, risk of craniosynostosis

    PubMed Central

    Pandey, Rajeev Kumar; Ali, Abid; Singh, Amit; Gayan, Sukanya; Bajpai, Minu

    2014-01-01

    BACKGROUND: 677C to T allele in the 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene has been implicated in the etiology of various syndromes and nonsyndromic diseases but till date no direct studies have been reported with craniosynostosis. OBJECTIVES: The aim was to study the family-based association of MTHFR polymorphism in different categories of craniosynostosis patients. MATERIALS AND METHODS: This was a cross-sectional study in which 30 patients classified as Apert syndrome, Pfeiffr syndrome and nonsyndromic craniosynostosis patients with their family were recruited. A sample of 3 ml intravenous blood was taken from patients and from their family members (father and mother) in ethylenediaminetetraacetic acid-anticoagulated vacutainer for the purpose of the study. Genomic DNA was extracted from peripheral blood lymphocytes by phenol chloroform extraction method. Primers for MTHFR gene were designed. The polymerase chain reaction was carried out. After successful amplification, a small aliquot (5 ?l) of the MTHFR reaction mixture was treated with 1 units of Hinf I restriction enzyme (NEB). Results were obtained and compiled. RESULTS: A total of 30 patients/participants with craniosynostosis of Indian descent and their parents formed the study group. The genotyping did not confirm an association between the MTHFR 677C to T polymorphism and between different categories of craniosynostosis. When comparing the offspring of mothers statistically significant differences were found. CONCLUSION: C667T polymorphism of the MTHFR gene is unlikely to play a role in the pathogenesis of craniosynostosis though maternal MTHFR C677T polymorphism may be a genetic risk factor. PMID:25400344

  20. MTHFR 677C 3 T genotype disrupts prefrontal function in schizophrenia through an interaction

    E-print Network

    Manoach, Dara S.

    MTHFR 677C 3 T genotype disrupts prefrontal function in schizophrenia through an interaction-specific effects. A second polymorphism, methylenetetrahydrofolate re- ductase (MTHFR) 677C 3 T (rs1801133), has controls. Further, significant MTHFR COMT genotype interactions were observed, which differed by diagnostic

  1. ORIGINAL RESEARCH MTHFR 677C>T effects on anterior cingulate structure

    E-print Network

    Manoach, Dara S.

    ORIGINAL RESEARCH MTHFR 677C>T effects on anterior cingulate structure and function during response heritable alterations of dACC function. We examined whether the hypofunctional 677C>T variant in MTHFR fractional anisotropy in bilateral dACC. These findings suggest that the MTHFR 677T allele blunts response

  2. The maize brown midrib2 (bm2) gene encodes a methylenetetrahydrofolate reductase that contributes to lignin accumulation

    PubMed Central

    Tang, Ho Man; Liu, Sanzhen; Hill-Skinner, Sarah; Wu, Wei; Reed, Danielle; Yeh, Cheng-Ting; Nettleton, Dan; Schnable, Patrick S

    2014-01-01

    The midribs of maize brown midrib (bm) mutants exhibit a reddish-brown color associated with reductions in lignin concentration and alterations in lignin composition. Here, we report the mapping, cloning, and functional and biochemical analyses of the bm2 gene. The bm2 gene was mapped to a small region of chromosome 1 that contains a putative methylenetetrahydrofolate reductase (MTHFR) gene, which is down-regulated in bm2 mutant plants. Analyses of multiple Mu-induced bm2-Mu mutant alleles confirmed that this constitutively expressed gene is bm2. Yeast complementation experiments and a previously published biochemical characterization show that the bm2 gene encodes a functional MTHFR. Quantitative RT-PCR analyses demonstrated that the bm2 mutants accumulate substantially reduced levels of bm2 transcript. Alteration of MTHFR function is expected to influence accumulation of the methyl donor S-adenosyl-l-methionine (SAM). Because SAM is consumed by two methyltransferases in the lignin pathway (Ye et al., 1994), the finding that bm2 encodes a functional MTHFR is consistent with its lignin phenotype. Consistent with this functional assignment of bm2, the expression patterns of genes in a variety of SAM-dependent or -related pathways, including lignin biosynthesis, are altered in the bm2 mutant. Biochemical assays confirmed that bm2 mutants accumulate reduced levels of lignin with altered composition compared to wild-type. Hence, this study demonstrates a role for MTHFR in lignin biosynthesis. PMID:24286468

  3. Conversion of a Peroxiredoxin into a Disulfide Reductase by a Triplet Repeat Expansion

    Microsoft Academic Search

    Daniel Ritz; Jackie Lim; C. Michael Reynolds; Leslie B. Poole; Jon Beckwith

    2001-01-01

    Pathways for the reduction of protein disulfide bonds are found in all organisms and are required for the reductive recycling of certain enzymes including the essential protein ribonucleotide reductase. An Escherichia coli strain that lacks both thioredoxin reductase and glutathione reductase grows extremely poorly. Here, we show that a mutation occurring at high frequencies in the gene ahpC, encoding a

  4. [Prevalence of factor V Leiden, hyperhomocysteinemia, prothrombin G20210A, and methylene tetrahydrofolate reductase C677T mutations in obstetrical complications].

    PubMed

    Verdy, E; Berkane, N; Magdelaine, A; Soubrier, F; Uzan, S

    1999-01-01

    The etiology and pathogenesis of intrauterine fetal death, preeclampsia or fetal growth retardation remain still unknown in many cases. However, placental thrombosis and/or infarction might lead to inadequate maternal-fetal circulation. So, the relevance of an additional thrombotic risk factor that enhances the physiological hypercoagulable state of gestation has been suggested in the development of these adverse outcomes of pregnancy. Several genetic mutations are newly recognized associated with an increased frequency of venous thrombosis: mutation of adenine to guanine at nucleotide 506 in the factor V gene, mutation of cytosine at nucleotide 677 in the methylenetetrahydrofolate gene and mutation of guanine to adenine at nucleotide 20210 in the prothrombin gene. In this issue, a review of literature has allowed us to evaluate the prevalence of these genetic predisposing thrombotic factors with the development of obstetrical complications. Furthermore, therapeutic approach is considered. PMID:10518055

  5. A Hypomethylating Variant of MTHFR, 677C>T, Blunts the Neural Response to Errors in Patients with Schizophrenia and Healthy Individuals

    PubMed Central

    Roffman, Joshua L.; Nitenson, Adam Z.; Agam, Yigal; Isom, Marlisa; Dyckman, Kara A.; Brohawn, David G.; Smoller, Jordan W.; Goff, Donald C.; Manoach, Dara S.

    2011-01-01

    Background Responding to errors is a critical first step in learning from mistakes, a process that is abnormal in schizophrenia. To gain insight into the neural and molecular mechanisms of error processing, we used functional MRI to examine effects of a genetic variant in methylenetetrahydrofolate reductase (MTHFR 677C>T, rs1801133) that increases risk for schizophrenia and that has been specifically associated with increased perseverative errors among patients. MTHFR is a key regulator of the intracellular one-carbon milieu, including DNA methylation, and each copy of the 677T allele reduces MTHFR activity by 35%. Methodology/Principal Findings Using an antisaccade paradigm, we found that the 677T allele induces a dose-dependent blunting of dorsal anterior cingulate cortex (dACC) activation in response to errors, a pattern that was identical in healthy individuals and patients with schizophrenia. Further, the normal relationship between dACC activation and error rate was disrupted among carriers of the 677T allele. Conclusions/Significance These findings implicate an epigenetic mechanism in the neural response to errors, and provide insight into normal cognitive variation through a schizophrenia risk gene. PMID:21980405

  6. Sex Differences in Ethanol’s Anxiolytic Effect and Chronic Ethanol Withdrawal Severity in Mice With a Null Mutation of the 5?-Reductase Type 1 Gene

    PubMed Central

    Tanchuck-Nipper, Michelle A.; Ford, Matthew M.; Hertzberg, Anna; Beadles-Bohling, Amy; Cozzoli, Debra K.; Finn, Deborah A.

    2015-01-01

    Manipulation of endogenous levels of the GABAergic neurosteroid allopregnanolone alters sensitivity to some effects of ethanol. Chronic ethanol withdrawal decreases activity and expression of 5?-reductase-1, an important enzyme in allopregnanolone biosynthesis encoded by the 5?-reductase-1 gene (Srd5a1). The present studies examined the impact of Srd5a1 deletion in male and female mice on several acute effects of ethanol and on chronic ethanol withdrawal severity. Genotype and sex did not differentially alter ethanol-induced hypothermia, ataxia, hypnosis, or metabolism, but ethanol withdrawal was significantly lower in female versus male mice. On the elevated plus maze, deletion of the Srd5a1 gene significantly decreased ethanol’s effect on total entries versus wildtype (WT) mice and significantly decreased ethanol’s anxiolytic effect in female knockout (KO) versus WT mice. The limited sex differences in the ability of Srd5a1 genotype to modulate select ethanol effects may reflect an interaction between developmental compensations to deletion of the Srd5a1 gene with sex hormones and levels of endogenous neurosteroids. PMID:25355320

  7. Genetic interactions between MTHFR (C677T), methionine synthase (A2756G, C2758G) variants with vitamin B12 and folic acid determine susceptibility to premature coronary artery disease in Indian population

    PubMed Central

    Kanth, V. V. Ravi; Golla, Jaya Prakash; Sastry, B. K. S; Naik, Sudhir; Kabra, Nitin; Sujatha, Madireddi

    2011-01-01

    Background: Researchers have determined that Indians face a higher risk of heart disease, despite the fact that nearly half of them are vegetarians and lack many of the other traditional risk factors. In the below-30 age group, coronary artery disease mortality among Indians is three-fold higher than in the whites in United Kingdom and ten-fold higher than the Chinese in Singapore. High levels of homocysteine have been widely linked to the early onset of heart diseases in other populations, although a definite proof among Indians is lacking, which needs to be investigated by way of screening for factors responsible for high homocysteine levels. Objective: To screen for genetic factors responsible for hyperhomocysteinemia and the risk for premature coronary artery disease. Materials and Methods: A total of 100 individuals with proven premature coronary artery disease and 200 age-and-sex matched controls were screened for polymorphisms in Methylenetetrahydrofolate reductase (MTHFR) (C677T) Methionine synthase (MS) genes (A2756G, C2758G), and the B12 and Folate levels were estimated. Results: Results from the mutational analysis revealed that in the study group, seven individuals had a polymorphism for the C677T allele in the MTHFR gene (one homozygous and six heterozygous) (Fischer's Exact test P > 0.046) (OR: 0.2711 95% CI 0.0774 to 0.9491). Six were heterozygous for the A2756G polymorphism in the MS gene (Fischer's Exact test P > 0.0012). None showed a polymorphism at the C2758G allele in the MS gene. Four controls showed heterozygosity for the C677T polymorphism and none for the MS gene. The B12 and Folate levels were significantly lower in the study group as compared to the controls. Conclusions: It is important to know which factors determine the total homocysteine concentrations. In the general population, the most important modifiable determinants of tHcy are folate intake and coffee consumption. Smoking and alcohol consumption are also associated with the total homocysteine concentrations, but more research is necessary to elucidate whether these relations are not originating from residual confounding due to other lifestyle factors. PMID:22022143

  8. Colorectal Cancer and the Methylenetetrahydrofolate Reductase 677C ! T and Methionine Synthase 2756A ! G Polymorphisms: A Study of 2,168 Case-Control Pairs from the JANUS Cohort

    Microsoft Academic Search

    Arve Ulvik; Stein Emil Vollset; Svein Hansen; Randi Gislefoss; Egil Jellum

    Polymorphisms in genes involved in the metabolism of folate and methyl groups have been implicated with risk of colorectal cancer. We evaluated the relation be- tween the polymorphisms 677C ! T of the methylene- tetrahydrofolate reductase (MTHFR) and 2756A ! G of the methionine synthase (MTR) genes and risk of colorectal cancer. From the Norwegian JANUS cohort of 309,000 subjects,

  9. The Genetic Diversity and Structure of Linkage Disequilibrium of the MTHFR Gene in Populations of Northern Eurasia

    PubMed Central

    Trifonova, E.A.; Eremina, E.R.; Urnov, F.D.; Stepanov, V.A.

    2012-01-01

    The structure of the haplotypes and linkage disequilibrium (LD) of the methylenetetrahydrofolate reductase gene (MTHFR) in 9 population groups from Northern Eurasia and populations of the international HapMap project was investigated in the present study. The data suggest that the architecture of LD in the human genome is largely determined by the evolutionary history of populations; however, the results of phylogenetic and haplotype analyses seems to suggest that in fact there may be a common “old” mechanism for the formation of certain patterns of LD. Variability in the structure of LD and the level of diversity of MTHFRhaplotypes cause a certain set of tagSNPs with an established prognostic significance for each population. In our opinion, the results obtained in the present study are of considerable interest for understanding multiple genetic phenomena: namely, the association of interpopulation differences in the patterns of LD with structures possessing a genetic susceptibility to complex diseases, and the functional significance of the pleiotropicMTHFR gene effect. Summarizing the results of this study, a conclusion can be made that the genetic variability analysis with emphasis on the structure of LD in human populations is a powerful tool that can make a significant contribution to such areas of biomedical science as human evolutionary biology, functional genomics, genetics of complex diseases, and pharmacogenomics. PMID:22708063

  10. Methylenetetrahydrofolate reductase polymorphism is not risk factor for Down syndrome in North India

    PubMed Central

    Rai, Vandana; Yadav, Upendra; Kumar, Pradeep; Yadav, Sushil Kumar

    2014-01-01

    BACKGROUND: Down syndrome (DS) is the most common cause of mental retardation of genetic etiology with the prevalence rate of 1/700 to 1/1000 live births worldwide. Several polymorphisms in folate/homocysteine metabolism pathways genes have been reported as a risk factor in women for bearing DS child, but very few studies investigated these polymorphisms in DS cases whether there are a risk factor for being DS or not. OBJECTIVE: We have investigated the association of methylenetetrahydrofolate reductase (MTHFR) with the occurrence of DS in Indian population. MTHFR is one of the key regulatory enzymes involved in the metabolic pathway of homocysteine responsible for the reduction of methyltetrahydrofolate. A total of 32 DS cases and 64 age, sex matched controls were genotyped for MTHFR C677T polymorphism by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: The observed genotype frequencies were CC = 0.81; CT = 0.17 and TT = 0.02 in controls and CC = 0.81 and CT = 0.19 in DS cases. Frequency of T allele in DS and controls were 0.09 and 0.1, respectively. Significant difference in the distribution of mutant 677T allele was not observed between DS cases and controls (odds ratio = 0.915; 95% confidence intervals: 0.331-2.53; P = 0.864). CONCLUSION: Results of this study indicate that MTHFR C677T polymorphism is not risk factor for DS. PMID:25400341

  11. Conversion of Human Steroid 5[beta]-Reductase (AKR1D1) into 3[beta]-Hydroxysteroid Dehydrogenase by Single Point Mutation E120H: Example of Perfect Enzyme Engineering

    SciTech Connect

    Chen, Mo; Drury, Jason E.; Christianson, David W.; Penning, Trevor M. (UPENN)

    2012-10-10

    Human aldo-keto reductase 1D1 (AKR1D1) and AKR1C enzymes are essential for bile acid biosynthesis and steroid hormone metabolism. AKR1D1 catalyzes the 5{beta}-reduction of {Delta}{sup 4}-3-ketosteroids, whereas AKR1C enzymes are hydroxysteroid dehydrogenases (HSDs). These enzymes share high sequence identity and catalyze 4-pro-(R)-hydride transfer from NADPH to an electrophilic carbon but differ in that one residue in the conserved AKR catalytic tetrad, His120 (AKR1D1 numbering), is substituted by a glutamate in AKR1D1. We find that the AKR1D1 E120H mutant abolishes 5{beta}-reductase activity and introduces HSD activity. However, the E120H mutant unexpectedly favors dihydrosteroids with the 5{alpha}-configuration and, unlike most of the AKR1C enzymes, shows a dominant stereochemical preference to act as a 3{beta}-HSD as opposed to a 3{alpha}-HSD. The catalytic efficiency achieved for 3{beta}-HSD activity is higher than that observed for any AKR to date. High resolution crystal structures of the E120H mutant in complex with epiandrosterone, 5{beta}-dihydrotestosterone, and {Delta}{sup 4}-androstene-3,17-dione elucidated the structural basis for this functional change. The glutamate-histidine substitution prevents a 3-ketosteroid from penetrating the active site so that hydride transfer is directed toward the C3 carbonyl group rather than the {Delta}{sup 4}-double bond and confers 3{beta}-HSD activity on the 5{beta}-reductase. Structures indicate that stereospecificity of HSD activity is achieved because the steroid flips over to present its {alpha}-face to the A-face of NADPH. This is in contrast to the AKR1C enzymes, which can invert stereochemistry when the steroid swings across the binding pocket. These studies show how a single point mutation in AKR1D1 can introduce HSD activity with unexpected configurational and stereochemical preference.

  12. Polymorphisms of the methylenetetrahydrofolate reductase gene and clinical outcomes in HLA-matched sibling allogeneic hematopoietic stem cell transplantation

    Microsoft Academic Search

    Inho Kim; Kyung-Hun Lee; Jin Hee Kim; Eun Kyung Ra; Sung-Soo Yoon; Yun-Chul Hong; Sung Sup Park; Chul Soo Kim; Byoung Kook Kim

    2007-01-01

    To evaluate whether the C677T and A1298C polymorphisms of 5,10-methylenetetrahydrofolate reductase (MTHFR) are related to the toxicity of methotrexate (MTX) used in allogeneic stem cell transplantation, we performed association analysis between these genetic polymorphisms and the clinical outcomes of patients treated using human leukocyte antigen-matched sibling stem cell transplantation. Patients (n=72) with hematological malignancy or aplastic anemia were given a

  13. Analysis of MTHFR Gene C.677C>T and C.1298A>C Polymorphisms in Iranian Patients with Non-Syndromic Cleft Lip and Palate

    PubMed Central

    JAHANBIN, Arezoo; HASANZADEH, Nadia; ABDOLHOSEINPOUR, Faraneh; SADR-NABAVI, Ariane; RAISOLSADAT, Mohammad-Ali; SHAMSIAN, Khosro; MOHAJERTEHRAN, Farnaz; KIANIFAR, Hamidreza

    2014-01-01

    Abstract Background Non-syndromic cleft lip with or without cleft palate (nsCL/P) is one of the most common congenital abnormalities of the orofacial region with a multifactorial etiology. The present study aimed to investigate the association of two common polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene (c.677C>T and c.1298A>C) with the occurrence of nsCL/P in an Iranian population. Methods Forty-five nsCL/P patients, 43 mothers of patients, and 101 unrelated controls participated in the present study. Analysis of c.677C>T and c.1298A>C polymorphisms in MTHFR gene was conducted using polymerase chain reaction and restriction enzyme digestions. Results There was no statistical difference in genotype and allele frequencies for c.677C>T variants between patients or their mothers and the control group. However, differences in the frequencies of alleles and genotypes of c.1298A>C polymorphism were statistically significant between patients and control group (P=0.01 for alleles and P=0.005 for genotypes). The odds ratios (OR) for the CC versus AA homozygotes were 6.1 (95% CI 1.8-20.5) and 4.2 (95% CI 1.1-15.4), in patients and mothers, respectively. Conclusions We found no association between genetic polymorphism of MTHFR c.677C>T and the risk of nsCL/P in the population studied. Yet the results suggested that c.1298A>C polymorphism of MTHFR gene may be a risk factor for the occurrence of nsCL/P in the Iranian population.

  14. Significance of dietary folate intake, homocysteine levels and MTHFR 677 C>T genotyping in South African patients diagnosed with depression: test development for clinical application.

    PubMed

    Delport, Darnielle; Schoeman, Renata; van der Merwe, Nicole; van der Merwe, Lize; Fisher, Leslie R; Geiger, Dieter; Kotze, Maritha J

    2014-06-01

    Low folate intake in the presence of the functional MTHFR 677 C > T (rs1801133) polymorphism is an important cause of elevated homocysteine levels previously implicated in major depressive disorder (MDD) and many other chronic diseases. In this study the clinical relevance and inter-relationship of these aspects were evaluated in 86 South African patients diagnosed with MDD and 97 population-matched controls participating in a chronic diseases screening program. A questionnaire-based clinical and nutrition assessment was performed, homocysteine levels determined, and all study participants genotyped for MTHFR 677 C > T (rs1801133) using allele-specific TaqMan technology. The folate score was found to be significantly lower in the patient group compared to controls (p?=?0.003) and correlated with increased body mass index (BMI), particularly in females with MDD (p?=?0.009). BMI was significantly higher in the MDD patients compared with controls after adjustment for age and sex (p?=?0.015), but this association was no longer significant after further adjustment for the level of folate intake in the diet. In MDD patients but not controls, the minor T-allele of MTHFR 677 C > T was associated with increased BMI (p?=?0.032), which in turn correlated significantly with increased homocysteine levels. The significant association between BMI and homocysteine levels was observed in both the MDD patient (p?=?0.049) and control (p?=?0.018) study groups. The significantly higher homocysteine levels observed in MDD patients compared to controls after adjustment for age and sex (p?=?0.030), therefore appears to be mediated by the effects of MTHFR 677 C > T and low folate intake on BMI. Detection of the low-penetrance MTHFR 677 C > T mutation reinforces the importance of folate intake above the recommended daily dose to prevent or restore dysfunction of the methylation pathway. PMID:24532086

  15. Association of polymorphisms in DNMT1, DNMT3A, DNMT3B, MTHFR and MTRR genes with global DNA methylation levels and prognosis of autoimmune thyroid disease.

    PubMed

    Arakawa, Y; Watanabe, M; Inoue, N; Sarumaru, M; Hidaka, Y; Iwatani, Y

    2012-11-01

    To clarify the association between factors regulating DNA methylation and the prognosis of autoimmune thyroid diseases (AITDs), we genotyped single nucleotide polymorphisms in genes encoding DNA methyltransferase 1 (DNMT1), DNMT3A, DNMT3B, methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR), which are enzymes essential for DNA methylation. Subjects for this study included 125 patients with Hashimoto's disease (HD), including 48 patients with severe HD and 49 patients with mild HD; 176 patients with Graves' disease (GD), including 79 patients with intractable GD and 47 patients with GD in remission; and 83 healthy volunteers (control subjects). The DNMT1+32204GG genotype was more frequent in patients with intractable GD than in patients with GD in remission. Genomic DNA showed significantly lower levels of global methylation in individuals with the DNMT1+32204GG genotype than in those with the AA genotype. The MTRR+66AA genotype was observed to be more frequent in patients with severe HD than in those with mild HD. The DNMT1+14395A/G, DNMT3B-579G/T, MTHFR+677C/T and +1298A/C polymorphisms were not correlated with the development or prognosis of AITD. Our study indicates that the DNMT1+32204GG genotype correlates with DNA hypomethylation and with the intractability of GD, and that the MTRR+66AA genotype may correlate with the severity of HD. PMID:23039890

  16. Mutation of alkyl hydroperoxide reductase gene ahpC of Xanthomonas oryzae pv. oryzae affects hydrogen peroxide accumulation during the rice-pathogen interaction.

    PubMed

    Li, Xin; Qiao, Jiaju; Yang, Lipeng; Li, Xinling; Qiao, Suyu; Pang, Xinyue; Tian, Fang; Chen, Huamin; He, Chenyang

    2014-10-01

    Hydrogen peroxide (H2O2) is usually generated by normal aerobic respiration of pathogens and by the host defense response during plant-pathogen interactions. In this study, histochemical localization of H2O2 accumulation in rice inoculated with the wild-type strain (PXO99(A)) and the gene deletion mutant (?ahpC) of alkyl hydroperoxide reductase subunit C (AhpC) of Xanthomonas oryzae pv. oryzae (Xoo), the bacterial blight pathogen of rice, was analyzed. The ?ahpC mutant displayed a significant decrease in endogenous H2O2 accumulation which was induced by the compensatory increase in H2O2 scavenging activity. The change in the bacterial endogenous H2O2 level affected the total amount of H2O2 accumulation during the interaction with rice plants. These results suggested that Xoo contributes to H2O2 accumulation in rice in a compatible interaction, and pathogen-driving H2O2 is in association with cell collapse of rice. PMID:25084557

  17. Ex vivo expansion and selection of human CD34+ peripheral blood progenitor cells after introduction of a mutated dihydrofolate reductase cDNA via retroviral gene transfer.

    PubMed

    Flasshove, M; Banerjee, D; Mineishi, S; Li, M X; Bertino, J R; Moore, M A

    1995-01-15

    Retroviral gene transfer into human myeloid precursor cells allows introduction of marker genes as well as genes conferring resistance to chemotherapeutic drugs. We transduced a human mutant dihydrofolate reductase (DHFR) cDNA into CD34 antigen-positive peripheral blood cells from patients with breast or ovarian cancer obtained after treatment with chemotherapy and granulocyte colony-stimulating factor (G-CSF). This mutant DHFR has been shown to confer resistance to methotrexate (MTX) in murine bone marrow. We established a transduction protocol that permitted ex vivo expansion and selection of transduced early progenitor cells. The number of progenitor cells from transduced CD34-positive cells increased 50-fold after cytokine prestimulation with interleukin-1 (IL-1), c-kit ligand (KL; stem cell factor), and IL-3 and 2 weeks in liquid culture. Transduced colony-forming unit-granulocyte-macrophage (CFU-GM), assayed directly after the transduction procedure, were protected completely against 2 x 10(-8) mol/L MTX, a concentration that significantly reduced the CFU-GM detected in the control population. Gene transfer of the mutant DHFR led to a twofold selective advantage for a pre-CFU population after exposure to MTX in liquid culture (P < .001). Polybrene, in contrast with protamine, significantly inhibited the expansion of progenitors. The presence of proviral DNA was monitored by polymerase chain reaction (PCR) and was detected in greater than 80% of CFU-GM and ex vivo expanded pre-CFU. We have demonstrated that human hematopoietic precursor cells can be expanded extensively after retroviral gene transfer. The same population of early progenitors can be selected ex vivo with low-dose MTX. As long-term expression of transduced genes in human hematopoietic cells remains a problem in vivo, these results may have implications for future clinical trials, especially for the introduction of nonselectable genes. PMID:7529065

  18. Roles forMenaquinone andtheTwoTrimethylamine Oxide (TMAO)Reductases inTMAO Respiration inSalmonella typhimurium: Mu d(Apr lac) Insertion Mutations inmenand tor

    Microsoft Academic Search

    H. S. KWAN ANDE; L. BARRETT

    1983-01-01

    mutants which weredevoid ofTMAO reductase activity. None expressed thelacoperon. GroupIImutants werepartially defective inTMAO reductase. Electrophoretic studies revealed that theylacked theinducible TMAO reductase, butretained theconstitutive activity. Thegenotypic designation tor wassuggested forthese mutants. Thetormutation inonewaslocated between 80 and83U ontheS.typhimurium chromosome. Expression ofthelacoperon in these mutants wasnotaffected byair, TMAO,ornitrate. GroupIIImutants reduced little ornoTMAO invivo, buttheir extracts retained full capacity to reduce itwithmethyl viologen.

  19. Impact of methylenetetrahydrofolate reductase polymorphisms and folate intake on the risk of gastric cancer and their association with Helicobacter pylori infection and tumor site.

    PubMed

    Chen, J; Yuan, L; Duan, Y Q; Jiang, J Q; Zhang, R; Huang, Z J; Xiao, X R

    2014-01-01

    Folic acid and methylenetetrahydrofolate reductase (MTHFR) may both affect the development of human cancer. We conducted a population-based case-control study in a Chinese population to investigate the potential role of folate intake and MTHFR gene polymorphisms in gastric cancer, and their interaction with infection by Helicobacter pylori and tumor location. A total of 767 patients with newly diagnosed gastric cancer and 775 controls were selected for this study. Genotyping of MTHFR C677T and A1298C was conducted by TaqMan assays using the ABI Prism 7911HT Sequence Detection System, and information on folate intake was collected by questionnaire. Compared with the CC genotype of MTHFR C677T, the TT genotype was significantly associated with a decreased risk of gastric cancer when the analysis was adjusted for other potential risk factors. We found a marginal significantly decreased risk of gastric cancer for individuals carrying the T allele [adjusted odds ratio (OR) = 0.83; 95% confidence interval (CI) = 0.65-1.01]. We detected an inverse relationship between folate intake and risk of gastric cancer, and the adjusted ORs (95%CI) for moderate and high folate intake were 0.97 (0.74-1.25) and 0.64 (0.49-0.87), respectively. Moreover, H. pylori infection, folate intake, and location of the tumor showed a significant interaction with the MTHFR C677T polymorphism. Our study suggests a protective role of MTHFR 677TT and high folate intake against gastric cancer, and the effect of the MTHFR C677T genotype may differ by H. pylori infection, folate consumption, and tumor site. PMID:24615072

  20. Mutations and Polymorphisms in Genes Affecting Hemostasis Proteins and Homocysteine Metabolism in Children with Arterial Ischemic Stroke

    Microsoft Academic Search

    A. Komitopoulou; H. Platokouki; Z. Kapsimali; H. Pergantou; E. Adamtziki; S. Aronis

    2006-01-01

    Background: The pathogenesis of thrombosis in childhood seems to be multifactorial implicating genetic and environmental factors. Aim: To compare the distributions of mutations\\/polymorphisms in genes affecting hemostasis (factor V Leiden – FVL, FV H1298R-FVR2, FII 20210A, b-Fib 455G>A, FXIII V34L, PAI-1 4G, HPA-1b) or homocysteine metabolism (MTHFR C677T, MTHFR A1298C) among 90 children with arterial ischemic stroke (AIS) and 103

  1. MTHFR genetic polymorphisms may contribute to the risk of chronic myelogenous leukemia in adults: a meta-analysis of 12 genetic association studies.

    PubMed

    Li, Bin; Zhang, Jian; Wang, Lei; Li, Yan; Jin, Juping; Ai, Limei; Li, Chong; Li, Zhe; Mao, Shudan

    2014-05-01

    Chronic myelogenous leukemia (CML) is a complex disease with a genetic basis. The genetic association studies (GASs) that have investigated the association between adult CML and 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms have produced contradictory and inconclusive results. The aim of this meta-analysis is to provide a relatively comprehensive assessment of the association of these polymorphisms with adult CML risk. A literature search for eligible GAS published before September 15, 2013 was conducted in PubMed, Embase, Web of Science, Cochrane Library, and China National Knowledge Infrastructure (CNKI) databases. Pooled odds ratios (ORs) with their corresponding 95% confidence intervals (95% CIs) were used to evaluate the strength of the association under a fixed or random effect model according to heterogeneity test results. All analyses were performed using the Stata software, version 12.0. Twelve case-control studies were included in this meta-analysis with a total of 932 CML patients and 3,465 healthy controls. For MTHFR C677T (dbSNP: rs1801133, C>T), though the pooled ORs were not significant in the overall population, all the ORs greater than 1 suggested an increased risk of CML for carriers of the risk allele. However, stratified analysis based on genotyping method revealed a significant association in the PCR-restriction fragment length polymorphism (RFLP) subgroup, possibly as a result of heterogeneity. For MTHFR A1298C (dbSNP: rs1801131, A>C), the combined results showed that carriers of the C allele may be associated with a decreased risk of adult CML. Stratified analysis showed that the magnitude of this effect was especially significant among Asians, indicating ethnicity differences in adult CML susceptibility. This meta-analysis shows that the C allele of MTHFR A1298C may be associated with a decreased risk in adult CML, especially among Asians, while MTHFR C677T may not be associated with adult CML risk. However, the development of adult CML may be the result of gene-gene and gene-environment interactions, which should be considered in future individual GAS and subsequent meta-analyses. PMID:24379141

  2. Geographical Distribution of MTHFR C677T, A1298C and MTRR A66G Gene Polymorphisms in China: Findings from 15357 Adults of Han Nationality

    PubMed Central

    Yang, Boyi; Liu, Yuyan; Li, Yongfang; Fan, Shujun; Zhi, Xueyuan; Lu, Xiangxiang; Wang, Da; Zheng, Quanmei; Wang, Yinuo; Wang, Yanxun; Sun, Guifan

    2013-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR) C677T, A1298C and methionine synthase reductase (MTRR) A66G polymorphisms are important genetic determinants for homocysteine (Hcy) levels, and are associated with several disorders. These polymorphisms are heterogeneously distributed worldwide. Our objective was to explore the geographical distributions of these polymorphisms in China. Methodologies 15357 healthy adults were recruited from 10 regions. Buccal samples were collected and genomic DNA was isolated. Genotyping was performed using the fluorogenic 5?-nuclease assay. Principal Findings The prevalence of the three polymorphisms among different populations from China varied significantly and showed apparent geographical gradients. For MTHFR C677T, the frequencies of the 677T allele and the 677TT genotype were significantly higher among northern populations and ranged from the lowest values (24.0% and 6.4%, respectively) in Hainan (southern) to the highest values (63.1% and 40.8%, respectively) in Shandong (northern). For MTHFR A1298C, the 1298C allele and the 1298CC genotype frequencies were significantly higher among southern populations and increased from low values (13.1% and 1.4%, respectively) in Shandong to high values (25.7% and 6.7%, respectively) in Hainan. For A66G, the 66G allele and the 66GG genotype frequencies increased from lower values (23.7% and 5.4%, respectively) in Shandong to higher values (29.2% and 8.6%, respectively) in Hainan. The overall frequency of the 677T allele, 677TT genotype, 1298C allele, 1298CC genotype, 66G allele and 66GG genotype in the Chinese Han population was 45.2%, 23.2%, 18.6%, 3.9%, 25.7%, and 6.6%, respectively. No gender differences were found in the prevalence of both the MTHFR C677T and MTRR A66G polymorphisms. Conclusions This study indicates that there are marked geographical variations in the prevalence of the three polymorphisms among Chinese Han populations. Our baseline data may be useful for future researches in related fields. PMID:23472119

  3. Association of the C677T polymorphism in the methylenetetrahydrofolate reductase gene with breast cancer in a Mexican population.

    PubMed

    Ramos-Silva, A; Figuera, L E; Soto-Quintana, O M; Puebla-Pérez, A M; Ramírez-Patiño, R; Gutiérrez-Hurtado, I; Carrillo-Moreno, D I; Zúñiga-González, G M; Dávalos-Rodríguez, I P; Gallegos-Arreola, M P

    2015-01-01

    The methylenetetrahydrofolate reductase (MTHFR) gene plays an important role in the steps involved in the processing of amino acids. The analysis of polymorphisms in the MTHFR gene has revealed associations with cancer; in particular the C677T polymorphism, which has been suggested to affect folate metabolism, DNA methylation, synthesis, and repair, and to contribute to tumor promotion in the mammary gland. We examined the role of the C677T polymorphism in the MTHFR gene by comparing the C677T genotypes of 339 healthy Mexican women with those of 497 Mexican women with breast cancer (BC). The genotype frequencies observed in the controls and patients with BC were 10 and 21% for 677TT; 41 and 36% for 677CT; and 49 and 43% for 677CC, respectively. The odds ratio (OR) for the 677TT genotype was 2.5, with a 95% confidence interval (95%CI) of 1.6-3.8; P = 0.0001. The positive association was also evident when the distributions of the 677TT genotype in control and patients affected within the following two categories were compared to alcohol consumption (OR = 0.41; 95%CI = 0.19-0.86; P = 0.018); and high level glutamate-oxaloacetate transaminase (SGOT) (OR = 0.36; 95%CI = 0.15-0.83, P = 0.017). These results suggest that the 677TT genotype of the C677T polymorphism in the MTHFR gene is associated with BC susceptibility in the Mexican population. PMID:25966173

  4. Reduced breast cancer risk with increasing serum folate in a case–control study of the C677T genotype of the methylenetetrahydrofolate reductase gene

    Microsoft Academic Search

    J Beilby; D Ingram; R Hähnel; E Rossi

    2004-01-01

    Breast cancer risk may be associated with folate status or the C677T genotype of the methylenetetrahydrofolate reductase (MTHFR) gene. We compared serum folate concentrations and C677T genotype in 141 breast cancer patients and 109 age-matched controls. Serum folate was significantly lower in cases compared to controls (geometric means, 5.7 versus 6.6 ?g\\/l; P=0.005). Breast cancer risk was not associated with

  5. Exploring the Effects of Methylenetetrahydrofolate Reductase Gene Variants C677T and A1298C on the Risk of Orofacial Clefts in 261 Norwegian Case-Parent Triads

    Microsoft Academic Search

    Astanand Jugessur; Allen J. Wilcox; Rolv T. Lie; Jeffrey C. Murray; Jack A. Taylor

    2003-01-01

    Folic acid and the methylenetetrahydrofolate reductase (MTHFR) gene have both been implicated in the etiology of orofacial clefts. The authors selected 261 case-parent triads (173 cases with cleft lip with or without cleft palate (CL\\/P) and 88 cases with cleft palate only (CPO)) from a Norwegian population-based study of orofacial clefts (May 1996-1998). A case-parent triad design was used to

  6. Homocysteine and Coronary Heart Disease: Meta-analysis of MTHFR Case-Control Studies, Avoiding Publication Bias

    PubMed Central

    Verhoef, Petra; Dötsch-Klerk, Mariska; Lathrop, Mark; Xu, Peng; Nordestgaard, Børge G.; Holm, Hilma; Hopewell, Jemma C.; Saleheen, Danish; Tanaka, Toshihiro; Anand, Sonia S.; Chambers, John C.; Kleber, Marcus E.; Ouwehand, Willem H.; Yamada, Yoshiji; Elbers, Clara; Peters, Bas; Stewart, Alexandre F. R.; Reilly, Muredach M.; Thorand, Barbara; Yusuf, Salim; Engert, James C.; Assimes, Themistocles L.; Kooner, Jaspal; Danesh, John; Watkins, Hugh; Samani, Nilesh J.

    2012-01-01

    Background Moderately elevated blood levels of homocysteine are weakly correlated with coronary heart disease (CHD) risk, but causality remains uncertain. When folate levels are low, the TT genotype of the common C677T polymorphism (rs1801133) of the methylene tetrahydrofolate reductase gene (MTHFR) appreciably increases homocysteine levels, so “Mendelian randomization” studies using this variant as an instrumental variable could help test causality. Methods and Findings Nineteen unpublished datasets were obtained (total 48,175 CHD cases and 67,961 controls) in which multiple genetic variants had been measured, including MTHFR C677T. These datasets did not include measurements of blood homocysteine, but homocysteine levels would be expected to be about 20% higher with TT than with CC genotype in the populations studied. In meta-analyses of these unpublished datasets, the case-control CHD odds ratio (OR) and 95% CI comparing TT versus CC homozygotes was 1.02 (0.98–1.07; p?=?0.28) overall, and 1.01 (0.95–1.07) in unsupplemented low-folate populations. By contrast, in a slightly updated meta-analysis of the 86 published studies (28,617 CHD cases and 41,857 controls), the OR was 1.15 (1.09–1.21), significantly discrepant (p?=?0.001) with the OR in the unpublished datasets. Within the meta-analysis of published studies, the OR was 1.12 (1.04–1.21) in the 14 larger studies (those with variance of log OR<0.05; total 13,119 cases) and 1.18 (1.09–1.28) in the 72 smaller ones (total 15,498 cases). Conclusions The CI for the overall result from large unpublished datasets shows lifelong moderate homocysteine elevation has little or no effect on CHD. The discrepant overall result from previously published studies reflects publication bias or methodological problems. Please see later in the article for the Editors' Summary PMID:22363213

  7. Migraine and MTHFR C677T genotype in a population-based sample

    Microsoft Academic Search

    Ann I. Scher; Gisela M. Terwindt; W. M. Monique Verschuren; Mark C. Kruit; Henk J. Blom; Hisanori Kowa; Rune R. Frants; Arn M. J. M. van den Maagdenberg; Mark van Buchem; Michel D. Ferrari; Lenore J. Launer

    2006-01-01

    OBJECTIVE: Migraine with aura is associated with increased risk of stroke. The MTHFR C677T genotype has been associated with increased risk of migraine in selected clinical samples and with elevated homocysteine, a risk factor for stroke. We assessed the association of the MTHFR C677T variant with migraine and the mediating effect of cardiovascular risk factors and metabolic markers of genotype

  8. Effects of Maternal 5,10-Methylenetetrahydrofolate Reductase C677T and A1298C Polymorphisms and Tobacco Smoking on Infant Birth Weight in a Japanese Population

    PubMed Central

    Yila, Thamar Ayo; Sasaki, Seiko; Miyashita, Chihiro; Braimoh, Titilola Serifat; Kashino, Ikuko; Kobayashi, Sumitaka; Okada, Emiko; Baba, Toshiaki; Yoshioka, Eiji; Minakami, Hisanori; Endo, Toshiaki; Sengoku, Kazuo; Kishi, Reiko

    2012-01-01

    Background Intracellular folate hemostasis depends on the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene. Because 5,10-MTHFR 677TT homozygosity and tobacco smoking are associated with low folate status, we tested the hypothesis that smoking in mothers with 5,10-MTHFR C677T or A1298C polymorphisms would be independently associated with lower birth weight among their offspring. Methods We assessed 1784 native Japanese mother-child pairs drawn from the ongoing birth cohort of The Hokkaido Study on Environment and Children’s Health. Data (demographic information, hospital birth records, and biological specimens) were extracted from recruitments that took place during the period from February 2003 to March 2006. Maternal serum folate were assayed by chemiluminescent immunoassay, and genotyping of 5,10-MTHFR C677T/A1298C polymorphisms was done using a TaqMan allelic discrimination assay. Results The prevalence of folate deficiency (<6.8 nmol/L) was 0.3%. The 5,10-MTHFR 677CT genotype was independently associated with an increase of 36.40 g (95% CI: 2.60 to 70.30, P = 0.035) in mean infant birth weight and an increase of 90.70 g (95% CI: 6.00 to 175.50, P = 0.036) among male infants of nonsmokers. Female infants of 677TT homozygous passive smokers were 99.00 g (95% CI: ?190.26 to ?7.56, P = 0.034) lighter. The birth weight of the offspring of smokers with 5,10-MTHFR 1298AA homozygosity was lower by 107.00 g (95% CI: ?180.00 to ?33.90, P = 0.004). Conclusions The results suggest that, in this population, maternal 5,10-MTHFR C677T polymorphism, but not the 5,10-MTHFR A1298C variant, is independently associated with improvement in infant birth weight, especially among nonsmokers. However, 5,10-MTHFR 1298AA might be associated with folate impairment and could interact with tobacco smoke to further decrease birth weight. PMID:22277790

  9. Methylenetetrahydrofolate Reductase Activity Is Involved in the Plasma Membrane Redox System Required for Pigment Biosynthesis in Filamentous Fungi ? †

    PubMed Central

    Frandsen, Rasmus J. N.; Albertsen, Klaus Selk; Stougaard, Peter; Sørensen, Jens L.; Nielsen, Kristian F.; Olsson, Stefan; Giese, Henriette

    2010-01-01

    Methylenetetrahydrofolate reductases (MTHFRs) play a key role in biosynthesis of methionine and S-adenosyl-l-methionine (SAM) via the recharging methionine biosynthetic pathway. Analysis of 32 complete fungal genomes showed that fungi were unique among eukaryotes by having two MTHFRs, MET12 and MET13. The MET12 type contained an additional conserved sequence motif compared to the sequences of MET13 and MTHFRs from other eukaryotes and bacteria. Targeted gene replacement of either of the two MTHFR encoding genes in Fusarium graminearum showed that they were essential for survival but could be rescued by exogenous methionine. The F. graminearum strain with a mutation of MET12 (Fg?MET12) displayed a delay in the production of the mycelium pigment aurofusarin and instead accumulated nor-rubrofusarin and rubrofusarin. High methionine concentrations or prolonged incubation eventually led to production of aurofusarin in the MET12 mutant. This suggested that the chemotype was caused by a lack of SAM units for the methylation of nor-rubrofusarin to yield rubrofusarin, thereby imposing a rate-limiting step in aurofusarin biosynthesis. The Fg?MET13 mutant, however, remained aurofusarin deficient at all tested methionine concentrations and instead accumulated nor-rubrofusarin and rubrofusarin. Analysis of MET13 mutants in F. graminearum and Aspergillus nidulans showed that both lacked extracellular reduction potential and were unable to complete mycelium pigment biosynthesis. These results are the first to show that MET13, in addition to its function in methionine biosynthesis, is required for the generation of the extracellular reduction potential necessary for pigment production in filamentous fungi. PMID:20543064

  10. Practical approach to steroid 5alpha-reductase type 2 deficiency

    Microsoft Academic Search

    Chong Kun Cheon

    2011-01-01

    The aim of this article is to review the literature on steroid 5alpha-reductase type 2 deficiency (5?-RD2) to provide clinicians\\u000a with information to guide their management of patients with this disorder. The 5alpha-reductase type 2 is encoded by the 5alpha-reductase\\u000a type 2 gene (SRD5A2) on chromosome 2 and is predominantly expressed in external genital tissues and the prostate. Mutations of

  11. The protective effect of methylenetetrahydrofolate reductase C677T polymorphism against prostate cancer risk: Evidence from 23 case-control studies.

    PubMed

    Guo, Shanqi; Jiang, Xingkang; Chen, Xiaobo; Chen, Liang; Li, Xiaojiang; Jia, Yingjie

    2015-07-01

    Genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) were considered to have some influence on both folate metabolism and cancer risk. Previous studies on the relation between MTHFR C677T polymorphism and prostate cancer (PCa) risk remained controversial. To derive a more precise estimation of the relationship, we carried out an update comprehensive meta-analysis to assess the associations of the MTHFR C677T polymorphism with the susceptibility of PCa. Twenty-three trials with a total of 24,024 participants on the MTHFR C677T polymorphism that met inclusion criteria were analyzed in the current study. Overall, no statistical relationship was found with any MTHFR C677T genetic model associated with susceptibility to PCa (TT versus CC, OR=0.83, 95% CI 0.68-1.02, P=0.07; CT versus CC, OR=0.95, 95% CI 0.85-1.07, P=0.43; Dominant, OR=0.93, 95% CI 0.83-1.03, P=0.17; Recessive, OR=0.84, 95% CI 0.70-1.02, P=0.09.). Nevertheless, subgroup analysis found a reduced PCa risk associated with polymorphism in Asian population (TT versus CC, CT versus CC, dominant and recessive model). Moreover, the protective effect of polymorphism against PCa risk was also shown upon hospital-based studies (TT versus CC, and recessive model). When benign prostate hyperplasia was chosen as controls, both TT versus CC and recessive model showed significant difference. In addition, the protective effect of homozygote TT against high aggressive PCa was proved to have significant difference. Taken together, the existing evidence indicates the homozygote TT of MTHFR C677T should be viewed as a protective factor against PCa risk for clinical practice with the consideration of different gene background, study design as well as specific controls. PMID:25841988

  12. Maternal Methylenetetrahydrofolate Reductase C677T Polymorphism and Down Syndrome Risk: A Meta-Analysis from 34 Studies

    PubMed Central

    Rai, Vandana; Yadav, Upendra; Kumar, Pradeep; Yadav, Sushil Kumar; Mishra, Om Prakesh

    2014-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme of folate metabolic pathway which catalyzes the irreversible conversion of 5, 10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. 5-methyltetrahydrofolate donates methyl group for the methylation of homocysteine to methionine. Several studies have investigated maternal MTHFR C677T polymorphism as a risk factor for DS, but the results were controversial and inconclusive. To come into a conclusive estimate, authors performed a meta-analysis. Aim A meta-analysis of published case control studies was performed to investigate the association between maternal MTHFR C677T polymorphism and Down syndrome. Methods PubMed, Google Scholar, Elsevier, Springer Link databases were searched to select the eligible case control studies using appropriate keywords. The pooled odds ratio (OR) with 95%confidence interval were calculated for risk assessment. Results Thirty four studies with 3,098 DS case mothers and 4,852 control mothers were included in the present meta-analysis. The pooled OR was estimated under five genetic models and significant association was found between maternal MTHFR 677C>T polymorphism and Down syndrome under four genetic models except recessive model (for T vs. C, OR?=?1.26, 95% CI?=?1.09–1.46, p?=?0.001; for TT vs. CC, OR?=?1.49, 95% CI?=?1.13–1.97, p?=?0.008; for CT vs. CC, OR?=?1.29, 95% CI?=?1.10–1.51, p?=?0.001; for TT+CT vs. CC, OR?=?1.35, 95% CI?=?1.13–1.60, p?=?0.0008; for TT vs. CT+CC, OR?=?0.76, 95% CI?=?0.60–0.94, p?=?0.01). Conclusion The results of the present meta-analysis support that maternal MTHFR C677T polymorphism is a risk factor for DS- affected pregnancy. PMID:25265565

  13. Methylenetetrahydrofolate Reductase A1298C Polymorphism and Breast Cancer Risk: A Meta-analysis of 33 Studies

    PubMed Central

    Rai, V

    2014-01-01

    Methylenetetrahydrofolate reductase (MTHFR) enzyme is essential for DNA synthesis and DNA methylation, and its gene polymorphisms have been implicated as risk factors for birth defects, neurological disorders, and different types of cancers. Several studies have investigated the association between the MTHFR A1298C polymorphism and breast cancer (BC) risk, but the results were inconclusive. To assess the risk associated with MTHFR A1298C polymorphism, a comprehensive meta-analysis was performed. PubMed, Google Scholar, Elsevier and Springer Link databases were searched for case-control studies relating the association between MTHFR A1298C polymorphism and BC risk and estimated summary odds ratios (ORs) with confidence intervals (CIs) for assessment. Up to January 2014, 33 case-control studies involving 15,919 BC patients and 19,700 controls were included in the present meta-analysis. The results showed that the A1298C polymorphism was not associated with BC risk in all the five genetic models (C vs. A allele (allele contrast): OR = 0.99, 95% confidence interval (CI): 0.93–1.05; AC versus AA (heterozygote/codominant): OR = 0.97, 95% CI: 0.89–1.04; CC versus AA (homozygote): OR = 0.99, 95% CI: 0.91–1.06; CC + AC versus AA (dominant model): OR = 0.97, 95% CI: 0.90–1.05; and CC versus AC + AA (recessive model): OR = 0.99, 95% CI: 0.91–1.07). The present meta-analysis did not support any association between the MTHFR A1298C polymorphism and BC risk. PMID:25506474

  14. Methylenetetrahydrofolate reductase gene variants and antipsychotic-induced weight gain and metabolic disturbances.

    PubMed

    Kao, A C C; Rojnic Kuzman, M; Tiwari, A K; Zivkovic, M V; Chowdhury, N I; Medved, V; Kekin, I; Zai, C C; Lieberman, J A; Meltzer, H Y; Bozina, T; Bozina, N; Kennedy, J L; Sertic, J; Müller, D J

    2014-07-01

    Weight gain and metabolic disturbances represent serious side-effects in antipsychotic (AP) treatment, particularly with clozapine and olanzapine. The methylenetetrahydrofolate reductase (MTHFR) gene is a key determinant in the folate metabolism and previous studies reported a significant effect on AP-induced weight gain and related metabolic abnormalities. Thus, we investigated MTHFR gene variants and changes in several important metabolic parameters in AP-treated patients. In this study, two functional MTHFR polymorphisms, rs1801133 (C677T) and rs1801131 (A1298C), were investigated for changes in weight and metabolic parameters. Genotypic associations were evaluated in a large population (n = 347 including 66 first episode psychosis, FEP patients) treated mostly with clozapine and olanzapine. We did not detect any genotypic association with weight changes (p > 0.05) in our total sample and in the sample refined for ancestry and medication. In our allelic analyses, we observed a trend for the 677-C allele to be associated with weight gain in the total sample (p = 0.03). This effect appeared to be driven by the FEP patients where those carrying the C-allele gained, on average, twice as much weight. Exploratory analyses revealed a significant association between the C677T and the A1298C polymorphism with HDL cholesterol serum levels in patients (p = 0.031). Overall we did not detect a major effect of two functional MTHFR gene variants and AP-induced weight gain. However, our findings suggest an effect of the C677T polymorphism in FEP patients and changes in weight and cholesterol levels. Further investigations in a larger sample are required. PMID:24725652

  15. Methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and gastric cancer susceptibility

    PubMed Central

    Xia, Lei-Zhou; Liu, Yi; Xu, Xiao-Zhou; Jiang, Peng-Cheng; Ma, Gui; Bu, Xue-Feng; Zhang, Yong-Jun; Yu, Feng; Xu, Ke-Sen; Li, Hua

    2014-01-01

    AIM: To identify the association between methylenetetrahydrofolate reductase (MTHFR) polymorphisms and gastric cancer (GC) susceptibility. METHODS: Systematic searches were performed on the electronic databases PubMed, ISI, Web of knowledge, CNKI and Wanfang, as well as manual searching of the references of the identified articles. A total of 26 papers were included in this meta-analysis. Overall and subgroup analyses were performed. Odds ratio (OR) and 95%CI were used to evaluate the associations between MTHFR polymorphisms and GC risk. The I2 statistics were used to evaluate between-study heterogeneity. Sensitivity analysis was also performed. RESULTS: Increased risk was found for the MTHFR C677T polymorphism under four genetic models (TT + CT vs CC: OR = 1.23, P = 0.002; T vs C: OR = 1.15, P = 0.001; TT vs CC: OR = 1.37, P = 0.0005; TT vs CT + CC: OR = 1.17, P = 0.0008). Subgroup analysis by ethnicity suggested that C677T polymorphism conferred a risk of GC in eastern but not in western populations. Stratification by tumor site showed an association between the C677T polymorphism and gastric cardia cancer and non-cardia GC in the worldwide population and in eastern populations. Regardless of comparisons with controls or diffuse-type GC, a positive association was found for the C677T polymorphism and an increased risk of intestinal-type GC in the whole population and in western populations. With regard to the A1298C polymorphism, we found that genotype CC was significantly decreased and conferred protection against GC in eastern populations (CC vs AA: OR = 0.44, P = 0.03; CC vs AC + AA: OR = 0.46, P = 0.04). CONCLUSION: MTHFR C677T polymorphism is a risk factor for GC, and the A1298C polymorphism may be a protective factor against GC in eastern populations. PMID:25170232

  16. Association between Maternal MTHFR Polymorphisms and Nonsyndromic Cleft Lip with or without Cleft Palate in Offspring, A Meta-Analysis Based on 15 Case-Control Studies

    PubMed Central

    Pan, Xinjuan; Wang, Ping; Yin, Xinjuan; Liu, Xiaozhuan; Li, Di; Li, Xing; Wang, Yongchao; Li, Hongle; Yu, Zengli

    2015-01-01

    Background The methylenetetrahydrofolate reductase (MTHFR) is thought to be involved in the development of nonsyndromic cleft lip with or without cleft palate (NSCL/P). However, conflicting results have been obtained when evaluating the association between maternal MTHFR C677T and A1298C polymorphisms and the risk of NSCL/P. In light of this gap, a meta-analysis of all eligible case-control studies was conducted in the present study. Materials and Methods A total of 15 case-control studies were ultimately identified after a comprehensive literature search and Hardy-Weinberg equilibrium (HWE) examination. Cochrane’s Q test and index of heterogeneity (I2) indicated no obvious heterogeneity among studies. Results Fixed or random-effects models were used to calculate the pooled odds ratios (ORs). The results showed that the TT genotype in mothers increased the likelihood of having NSCL/P offspring 1.25 times (95% CI: 1.047-1.494) more than the CC homozygotes. Meanwhile, maternal TT genotype increased the risk of producing NSCL/P offspring in recessive model (OR=1.325, 95% CI: 1.124-1.562). However, the CT heterozygote and the CT+TT dominant models had no association with NSCL/P offspring compared with the CC wild-type homozygote model. Subgroup analyses based on ethnicity indicated that maternal TT genotype increased the likelihood of having NSCL/P offspring in Whites (OR=1.308, 95% CI: 1.059-1.617) and Asians (OR=1.726, 95% CI: 1.090-2.733) in recessive model. Also, subgroup analyses based on source of control showed that mothers with the 677TT genotype had a significantly increased susceptibility of having NSCL/P children in hospital based population (HB) when compared with CC homozygotes (OR=1.248, 95% CI: 1.024-1.520) and un- der the recessive model (OR=1.324, 95% CI: 1.104-1.588). Furthermore, maternal A1298C polymorphism had no significant association with producing NSCL/P offspring (dominant model OR=0.952, 95% CI: 0.816-1.111, recessive model OR=0.766, 95% CI: 0.567-1.036). Conclusion MTHFR C677T polymorphism is associated with the risk of generating NSCL/P offspring, and being a 677TT homozygote is a risk factor. MTHFR A1298C polymorphism was not associated with generating NSCL/P offspring. However, further work should be performed to confirm these findings. PMID:25780529

  17. Relationship of MTHFR gene 677C ? T polymorphism, homocysteine, and estimated glomerular filtration rate levels with the risk of new-onset diabetes.

    PubMed

    Qin, Xianhui; Li, Youbao; Yuan, Hui; Xie, Di; Tang, Genfu; Wang, Binyan; Wang, Xiaobin; Xu, Xin; Xu, Xiping; Hou, Fanfan

    2015-02-01

    East Asian patients with diabetes have a higher risk for renal complications and strokes than Europeans. We aimed to evaluate the effect of methylenetetrahydrofolate reductase (MTHFR) gene 677 C ? T polymorphism, which was associated with a higher stroke risk and was common in the Chinese population, as well as homocysteine and estimated glomerular filtration rate (eGFR) levels on the risk of new-onset diabetes (NOD). A total of 2422 subjects without diabetes were followed-up for 7 years. NOD was defined as fasting plasma glucose ? 7.0 mmol/L or self-reported physician diagnosis of diabetes. Compared with subjects with MTHFR 677 CC genotype, those with TT genotype had a higher risk of NOD in females (odds ratio 2.78, 95% confidence interval 1.39-5.56) but not in males (0.80, 0.40-1.61, P for interaction = 0.008). Furthermore, MTHFR 677 C ? T polymorphism was more strongly associated with the risk of NOD among females with higher body mass index (BMI, ? 23 vs <23 kg/m(2), P for interaction = 0.009) or lower high-density lipoprotein-cholesterol (HDL-C, <1.3 vs ? 1.3 mmol/L, P for interaction = 0.015) levels. Hyperhomocysteinemia (? 16 vs <10 ?mol/L) was not significantly associated with NOD in males (0.88, 0.42-1.85) or females (1.52, 0.65-3.57). However, mildly decreased eGFR (<90 vs 90-120 mL/min/1.73 m(2)) was associated with NOD mainly in males (1.96, 1.01-3.78; females, 0.74, 0.32-1.72, P for interaction = 0.134). Females with MTHFR 677 TT genotype had a significantly higher risk of NOD, particularly those with higher BMI or low HDL-C levels. The higher risk of NOD associated with mildly decreased eGFR also warrants more investigation. Our results provide insights into the ethnic differences of diabetic complications between East Asian patients and Europeans. PMID:25700330

  18. Are MTHFR C677T and MTRR A66G Polymorphisms Associated with Overweight/Obesity Risk? From a Case-Control to a Meta-Analysis of 30,327 Subjects.

    PubMed

    Fan, Shu-Jun; Yang, Bo-Yi; Zhi, Xue-Yuan; He, Miao; Wang, Da; Wang, Yan-Xun; Wang, Yi-Nuo; Wei, Jian; Zheng, Quan-Mei; Sun, Gui-Fan

    2015-01-01

    Several studies have examined the associations of methylenetetrahydrofolate reductase (MTHFR) C677T and methionine synthase reductase (MTRR) A66G polymorphisms with being overweight/obesity. However, the results are still controversial. We therefore conducted a case-control study (517 cases and 741 controls) in a Chinese Han population and then performed a meta-analysis by combining previous studies (5431 cases and 24,896 controls). In our case-control study, the MTHFR C677T polymorphism was not significantly associated with being overweight/obesity when examining homozygous codominant, heterozygous codominant, dominant, recessive and allelic genetic models. The following meta-analysis confirmed our case-control results. Heterogeneity was minimal in the overall analysis, and sensitivity analyses and publication bias tests indicated that the meta-analytic results were reliable. Similarly, both the case-control study and meta-analysis found no significant association between the MTRR A66G polymorphism and being overweight/obesity. However, sensitivity analyses showed that the associations between the MTRR A66G polymorphism and being overweight/obesity became significant in the dominant, heterozygous codominant and allelic models after excluding our case-control study. The results from our case-control study and meta-analysis suggest that both of the two polymorphisms are not associated with being overweight/obesity. Further large-scale population-based studies, especially for the MTRR A66G polymorphism, are still needed to confirm or refute our findings. PMID:26016497

  19. Are MTHFR C677T and MTRR A66G Polymorphisms Associated with Overweight/Obesity Risk? From a Case-Control to a Meta-Analysis of 30,327 Subjects

    PubMed Central

    Fan, Shu-Jun; Yang, Bo-Yi; Zhi, Xue-Yuan; He, Miao; Wang, Da; Wang, Yan-Xun; Wang, Yi-Nuo; Wei, Jian; Zheng, Quan-Mei; Sun, Gui-Fan

    2015-01-01

    Several studies have examined the associations of methylenetetrahydrofolate reductase (MTHFR) C677T and methionine synthase reductase (MTRR) A66G polymorphisms with being overweight/obesity. However, the results are still controversial. We therefore conducted a case-control study (517 cases and 741 controls) in a Chinese Han population and then performed a meta-analysis by combining previous studies (5431 cases and 24,896 controls). In our case-control study, the MTHFR C677T polymorphism was not significantly associated with being overweight/obesity when examining homozygous codominant, heterozygous codominant, dominant, recessive and allelic genetic models. The following meta-analysis confirmed our case-control results. Heterogeneity was minimal in the overall analysis, and sensitivity analyses and publication bias tests indicated that the meta-analytic results were reliable. Similarly, both the case-control study and meta-analysis found no significant association between the MTRR A66G polymorphism and being overweight/obesity. However, sensitivity analyses showed that the associations between the MTRR A66G polymorphism and being overweight/obesity became significant in the dominant, heterozygous codominant and allelic models after excluding our case-control study. The results from our case-control study and meta-analysis suggest that both of the two polymorphisms are not associated with being overweight/obesity. Further large-scale population-based studies, especially for the MTRR A66G polymorphism, are still needed to confirm or refute our findings. PMID:26016497

  20. Association between methionine synthase reductase A66G polymorphism and primary infertility in Chinese males.

    PubMed

    Li, X Y; Ye, J Z; Ding, X P; Zhang, X H; Ma, T J; Zhong, R; Ren, H Y

    2015-01-01

    We examined the association between the methionine synthase reductase (MTRR A66G), methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), and methionine synthase (MS A2756G) genotypes and non-obstructive male infertility in a Chinese population. This case-control study included 162 infertile Chinese patients with azoospermia (N = 100) or oligoasthenozoospermia (N = 62) and 120 fertile men as controls. The polymorphisms MTRR A66G, MTHFR C677T, A1298C, and MS A2756G were identified by direct DNA sequencing and the results were statistically analyzed. We found no association between the incidence of any of these variants in azoospermia patients and control populations. The frequency of the MTRR66 polymorphic genotypes (AG, AG+GG) was significantly higher in the oligoasthenozoospermia group compared to the controls (P = 0.013, 0.012). Our findings revealed an association between the single-nucleotide polymorphism A66G in the MTRR gene and male infertility, particularly in oligoasthenozoospermia males, suggesting that this polymorphism is a genetic risk factor for male infertility in Chinese men. PMID:25966116

  1. 5,10-Methylenetetrahydrofolate reductase gene variants and congenital anomalies: a HuGE review.

    PubMed

    Botto, L D; Yang, Q

    2000-05-01

    The enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR) is involved in folate metabolism. The MTHFR gene is located on chromosome 1 (1p36.3), and two common alleles, the C677T (thermolabile) allele and the A1298C allele, have been described. The population frequency of C677T homozygosity ranges from 1% or less among Blacks from Africa and the United States to 20% or more among Italians and US Hispanics. C677T homozygosity in infants is associated with a moderately increased risk for spina bifida (pooled odds ratio = 1.8; 95% confidence interval: 1.4, 2.2). Maternal C677T homozygosity also appears to be a moderate risk factor (pooled odds ratio = 2.0; 95% confidence interval: 1.5, 2.8). The A 1298C allele combined with the C677T allele also could be associated with an increased risk for spina bifida. Some data suggest that the risk for spina bifida associated with C677T homozygosity may depend on nutritional status (e.g., blood folate levels, intake of vitamins) or on the genotype of other folate-related genes (e.g., cystathionine-beta-synthase and methionine synthase reductase). Studies of the C677T allele in relation to oral clefts, Down syndrome, and fetal anticonvulsant syndrome either have yielded conflicting results or have not been yet replicated. PMID:10791559

  2. Association between methylenetetrahydrofolate reductase C677T polymorphism and bone mineral density: the Dong-gu Study and the Namwon Study.

    PubMed

    Shin, Min-Ho; Choi, Jin-Su; Rhee, Jung-Ae; Lee, Young-Hoon; Nam, Hae-Sung; Jeong, Seul-Ki; Park, Kyeong-Soo; Kim, Hye-Yeon; Ryu, So-Yeon; Choi, Seong-Woo; Song, Hye-Rim; Kim, Hee Nam; Cauley, Jane A; Kweon, Sun-Seog

    2013-06-01

    The purpose of this study was to examine the association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and bone mineral density (BMD). Two large cohort studies were performed: the Dong-gu Study (3,621 men and 5,409 women) and the Namwon Study (3,703 men and 5,672 women). We assessed lumbar spine and femoral neck BMD by dual-energy X-ray absorptiometry. Genotypes were determined by real-time polymerase chain reaction. Multiple linear regression analysis was performed to evaluate the association between MTHFR C677T and BMD, adjusting for age, weight and height. The MTHFR C677T genotype frequencies for CC, CT, and TT genotypes were 34.5, 48.7, and 16.8%, respectively, in the Dong-gu Study and 33.6, 49.2, and 17.2%, respectively, in the Namwon Study. There are no significant differences between the MTHFR C677T genotype and the BMD at the lumbar spine and femoral neck in men or women in both cohorts. PMID:23772168

  3. Association between Methylenetetrahydrofolate Reductase C677T Polymorphism and Bone Mineral Density: The Dong-gu Study and the Namwon Study

    PubMed Central

    Shin, Min-Ho; Choi, Jin-Su; Rhee, Jung-Ae; Lee, Young-Hoon; Nam, Hae-Sung; Jeong, Seul-Ki; Park, Kyeong-Soo; Kim, Hye-Yeon; Ryu, So-Yeon; Choi, Seong-Woo; Song, Hye-Rim; Kim, Hee Nam; Cauley, Jane A.

    2013-01-01

    The purpose of this study was to examine the association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and bone mineral density (BMD). Two large cohort studies were performed: the Dong-gu Study (3,621 men and 5,409 women) and the Namwon Study (3,703 men and 5,672 women). We assessed lumbar spine and femoral neck BMD by dual-energy X-ray absorptiometry. Genotypes were determined by real-time polymerase chain reaction. Multiple linear regression analysis was performed to evaluate the association between MTHFR C677T and BMD, adjusting for age, weight and height. The MTHFR C677T genotype frequencies for CC, CT, and TT genotypes were 34.5, 48.7, and 16.8%, respectively, in the Dong-gu Study and 33.6, 49.2, and 17.2%, respectively, in the Namwon Study. There are no significant differences between the MTHFR C677T genotype and the BMD at the lumbar spine and femoral neck in men or women in both cohorts. PMID:23772168

  4. Methaemoglobin reductase deficiency in dogs

    Microsoft Academic Search

    J. W. Harvey; R. R. King; C. R. Berry; J. T. Blue

    1991-01-01

    Erythrocyte methaemoglobin reductase deficiency is described in a toy Alaskan Eskimo dog, a miniature poodle dog and a cocker\\/poodle cross dog. Blood methaemoglobin contents ranged from 19% to 36% of total haemoglobin, with methaemoglobin reductase values between 13% and 33% of normal. There appeared to be a negative linear correlation between erythrocyte methaemoglobin content and methaemoglobin reductase activity. A single

  5. No Association of Functional Polymorphisms in Methlylenetetrahydrofolate Reductase and the Risk and Minor Physical Anomalies of Schizophrenia in Korean Population

    PubMed Central

    Kim, Su-Gyeong; Song, Joo Yun; Joo, Eun-Jeong; Jeong, Seong Hoon; Kim, Se Hyun; Lee, Kyu Young; Lee, Nam Young; Ahn, Yong Min; Kim, Yong Sik

    2011-01-01

    Methylenetetrahydrofolate reductase (MTHFR), a critical enzyme in folate metabolism, plays an important role in DNA methylation. It has been suggested that abnormal DNA methylation contributes to the pathogenesis of schizophrenia and congenital anomalies. The previous findings regarding the genetic relationship between MTHFR and schizophrenia are controversial. This study investigated the association of the two functional polymorphisms of MTHFR, C677T and A1298C, with the risk for schizophrenia. Furthermore, we conducted an updated meta-analysis on the two polymorphisms. In addition, we investigated the relationship between the polymorphisms and minor physical anomaly (MPA), which may represent neurodevelopmental aberrations in 201 schizophrenia patients and 350 normal control subjects. There was no significant association between either of the two polymorphisms and the risk of schizophrenia (chi-square = 0.001, df = 1, P = 0.971 for C677T; chi-square = 1.319, df = 1, P = 0.251 for A1298C). However, in meta-analysis, the C677T polymorphism showed a significant association in the combined and Asian populations (OR = 1.13, P = 0.005; OR = 1.21, P = 0.011, respectively) but not in the Korean and Caucasian populations alone. Neither polymorphism was associated with MPAs measured by the Waldrop scale (chi-square = 2.513, df = 2, P = 0.285). In conclusion, the present findings suggest that in the Korean population, the MTHFR polymorphisms are unlikely to be associated with the risk for schizophrenia and neurodevelopmental abnormalities related to schizophrenia. PMID:22022190

  6. Association of dietary intake of folate and MTHFR genotype with breast cancer risk.

    PubMed

    Wang, Z G; Cui, W; Yang, L F; Zhu, Y Q; Wei, W H

    2014-01-01

    We conducted a hospital-based case-control study to investigate the associations of dietary intake of folate and MTHFR C677T and A1298C polymorphisms with breast cancer in a Chinese population. A 1:1-matched case-control study was conducted. Two hundred and thirty patients who were newly diagnosed and histologically confirmed breast cancer and 230 controls were enrolled from Xinxiang Central Hospital. Folate intake was calculated by standard portion size and relative size for each food item in the questionnaire. Genotyping of MTHFR C677T and A1298C was performed by PCR-RFLP. MTHFR 677TT (OR = 2.26, 95%CI = 1.09-4.87, P = 0.02) and T allele (OR = 1.40, 95%CI = 1.03-1.90, P = 0.03) had an increased risk of laryngeal cancer when compared with the CC genotype. We found any interaction between MTHFR C677T and folate intake (P for interaction = 0.02). In conclusion, our study demonstrated that MTHFR C677T polymorphism and folate are associated with risk of breast cancer. PMID:25078601

  7. Associations of variants in MTHFR and MTRR genes with male infertility in the Jordanian population.

    PubMed

    Mfady, Doaa S; Sadiq, May F; Khabour, Omar F; Fararjeh, Abdulfattah S; Abu-Awad, Aymen; Khader, Yousef

    2014-02-15

    Folate pathway is expected to play an important role in spermatogenesis since it is involved in DNA synthesis, repair and methylation. The purpose of this study was to examine the association between male infertility and the MTHFR (C677T and A1298C) and MTRR (A66G) polymorphisms. A group of 300 males was recruited in this study from different Jordanian infertility clinics. Of these, 150 cases of infertile men that included oligozoospermia cases (n=45), severe oligozoospermia (n=71) and azoospermia (n=34) were studied. The other 150 males were age matched fertile controls. Genotyping of MTHFR and MTRR polymorphisms was performed using PCR-RFLP technique. The results showed an association between MTHFR 677TT genotype and male infertility (P<0.05). However, the distribution of MTHFR A1298C and MTRR A66G genotypes were not different between the fertile and infertile groups (P>0.05). In addition, none of the examined polymorphisms was related to any of the semen parameters in the infertile group. In conclusion, this study showed that MTHFR C677T polymorphism is associated with male infertility in Jordanians. PMID:24334125

  8. Association between factor V Leiden, prothrombin G20210A, and methylenetetrahydrofolate reductase C677T mutations and events of the arterial circulatory system: a meta-analysis of published studies

    Microsoft Academic Search

    Robert J Kim; Richard C Becker

    2003-01-01

    BackgroundThe association between the inherited gene mutations of factor V, prothrombin, and homocysteine metabolism and venous thromboembolic events is accepted widely; however, their influence on the arterial circulatory system remains controversial.

  9. Methylation pattern of methylene tetrahydrofolate reductase and small nuclear ribonucleoprotein polypeptide N promoters in oligoasthenospermia: a case-control study.

    PubMed

    Botezatu, Anca; Socolov, Razvan; Socolov, Demetra; Iancu, Iulia Virginia; Anton, Gabriela

    2014-02-01

    Alterations in DNA methylation patterns in several genes may lead to abnormal male sexual development and infertility. This study investigated the promoter methylation status of MTHFR and SNRPN in infertile men from Romania by quantitative methylation-specific PCR in order to investigate possible correlations with sperm abnormalities. The study groups included patients (n=27) with a median age of 31 years (range 26-41 years) as well as controls (n=11) with a median age of 30 years (range 24-37 years) recruited from couples seeking advice for infertility. DNA was isolated from sperm samples and promoter methylation was assessed using direct. Significant trends were detected for both genes that indicate a tendency towards promoter hypermethylation in spermatozoa with low motility (MTHFR P=0.0032, r=0.23; SNRPN P=0.0003, r=0.32) and poor morphology (MTHFR P=0.0012, r=0.27; SNRPN P=0.0003, r=0.33) but no trend was found in cases of low sperm count (MTHFR r=0.007; SNRPN r=0.06). The data indicate that the methylation patterns of the promoters of MTHFR and SNRPN are associated with changes in sperm motility and morphology, which could lead to male infertility. A large number of studies are now focused on the causes of male infertility. Among these are epigenetic modifications, which are important contributors to reproductive pathology in the male by providing dynamic changes of the phenotype according to the environmental and metabolic factors. The most known epigenetic modification is DNA methylation and alterations in this pattern in several genes could induce male infertility. The present study aims to investigate the promoter methylation status of the genes for methylene tetrahydrofolate reductase (MTHFR) and small nuclear ribonucleoprotein polypeptide N (SNRPN) in infertile males from Romania, in order to establish a correlation with sperm parameters. MTHFR is an enzyme involved in the folate pathway and in de novo nucleotide biosynthesis but also a good example for gene-environment interaction in phenotype development. SNRPN is involved in both somatic cell expression and inheritance of the imprint and the methylation pattern of its gene seems to correlate not only with imprinted disorders but also with infertility. Our study includes patients (n=27, median age 31 years, range 26-41 years) recruited from men seeking advice for couple infertility and control group (n=11, median age 30.5 years, range 24-37 years). The data we obtained indicated significant correlations between hypermethylation of the investigated genes and sperm motility and morphology. No significant correlation between DNA methylation and sperm number was found. Our data suggest that methylation pattern of MTHFR and SNRPN is linked with sperm anomalies of motility and morphology and therefore male infertility. PMID:24365028

  10. Significance of 5,10-methylenetetrahydrofolate reductase gene variants in acute lymphoblastic leukemia in Indian population: an experimental, computational and meta-analysis.

    PubMed

    Bellampalli, Ravishankara; Phani, Nagaraja M; Bhat, Kamalakshi G; Prasad, Krishna; Bhaskaranand, Nalini; Guruprasad, Kanive P; Rai, Padmalatha S; Satyamoorthy, Kapaettu

    2015-05-01

    Acute lymphoblastic leukemia (ALL) arises due to several genetic alterations in progenitor cells, and methotrexate is frequently used as part of the treatment regimen. Although there is evidence for an effect of 5,10-methylenetetrahydrofolate reductase gene (MTHFR) C677T and A1298C variations on drug response in ALL, its risk association for ALL is still unresolved. In a case-control study of 203 patients with ALL and 246 controls and meta-analysis in the Indian population, we showed an insignificant association of MTHFR C677T and A1298C genotypes with childhood and adult ALL. Comprehensive in silico characterization of non-synonymous single nucleotide polymorphisms (nsSNPs) and SNPs of the 3' untranslated region (UTR) revealed nine nsSNPs as deleterious, and three SNPs in the 3'UTR could possibly alter the binding of miRNAs. The study revealed that several overlooked SNPs may contribute to the risk of ALL susceptibility and further studies of these SNPs with functional characterization in a large sample size are required to understand the significant role of MTHFR in ALL development. PMID:25115513

  11. Association between C677T Polymorphism of Methylene Tetrahydrofolate Reductase and Congenital Heart Disease: Meta-Analysis of 7,697 Cases and 13,125 Controls

    PubMed Central

    Mamasoula, Chrysovalanto; Prentice, R. Reid; Pierscionek, Tomasz; Pangilinan, Faith; Mills, James L.; Druschel, Charlotte; Pass, Kenneth; Russell, Mark W.; Hall, Darroch; Töpf, Ana; Brown, Danielle L.; Zelenika, Diana; Bentham, Jamie; Cosgrove, Catherine; Bhattacharya, Shoumo; Riveron, Javier Granados; Setchfield, Kerry; Brook, J. David; Bu'Lock, Frances A.; Thornborough, Chris; Rahman, Thahira J.; Doza, Julian Palomino; Tan, Huay L.; O'Sullivan, John; Stuart, A. Graham; Blue, Gillian; Winlaw, David; Postma, Alex V.; Mulder, Barbara J.M.; Zwinderman, Aelko H.; van Engelen, Klaartje; Moorman, Antoon F.M.; Rauch, Anita; Gewillig, Marc; Breckpot, Jeroen; Devriendt, Koen; Lathrop, G. Mark; Farrall, Martin; Goodship, Judith A.; Cordell, Heather J.; Brody, Lawrence C.; Keavney, Bernard D.

    2013-01-01

    Background Association between the C677T polymorphism of the methylene tetrahydrofolate reductase (MTHFR) gene and congenital heart disease (CHD) is contentious. Methods and Results We compared genotypes between CHD cases and controls, and between mothers of CHD cases and controls. We placed our results in context by conducting metaanalyses of previously published studies. Among 5,814 cases with primary genotype data and 10,056 controls, there was no evidence of association between MTHFR C677T genotype and CHD risk (OR 0.96 [95% CI 0.87-1.07]). A random-effects meta-analysis of all studies (involving 7,697 cases and 13,125 controls) suggested the presence of association (OR 1.25 [95% CI 1.03-1.51]; p=0.022), but with substantial heterogeneity among contributing studies (I2=64.4%), and evidence of publication bias. Meta-analysis of large studies only (defined by a variance of the log OR less than 0.05), which together contributed 83% of all cases, yielded no evidence of association (OR 0.97 [95% CI 0.91-1.03]), without significant heterogeneity (I2=0). Moreover, meta-analysis of 1,781 mothers of CHD cases (829 of whom were genotyped in this study) and 19,861 controls revealed no evidence of association between maternal C677T genotype and risk of CHD in offspring (OR 1.13 [95% CI 0.87-1.47]). There was no significant association between MTHFR genotype and CHD risk in large studies from regions with different levels of dietary folate. Conclusions The MTHFR C677T polymorphism, which directly influences plasma folate levels, is not associated with CHD risk. Publication biases appear to substantially contaminate the literature with regard to this genetic association. PMID:23876493

  12. No Association Between the Common MTHFR 677C?T Polymorphism and Venous Thrombosis Results From the MEGA Study

    Microsoft Academic Search

    Irene D. Bezemer; Carine J. M. Doggen; Hans L. Vos; Frits R. Rosendaal

    2007-01-01

    Results: MTHFR 677C?T was not associated with the risk of venous thrombosis (odds ratio (95% confidence interval), 0.99 (0.91-1.08) for the CT genotype and 0.94 (0.81-1.08)fortheTTgenotype).Stratificationbyknown risk factors for venous thrombosis provided no evi- dence of an association in specific groups. Conclusions: In a single large study, MTHFR 677C?T was not associated with the risk of venous thrombosis, andthenarrowconfidenceintervalexcludesevenasmall effect.

  13. Characterization of mitochondrial thioredoxin reductase from C. elegans

    SciTech Connect

    Lacey, Brian M. [Department of Biochemistry, 89 Beaumont Ave, Given Laboratory, Room B413, Burlington, VT 05405 (United States); Hondal, Robert J. [Department of Biochemistry, 89 Beaumont Ave, Given Laboratory, Room B413, Burlington, VT 05405 (United States)]. E-mail: Robert.Hondal@uvm.edu

    2006-08-04

    Thioredoxin reductase catalyzes the NADPH-dependent reduction of the catalytic disulfide bond of thioredoxin. In mammals and other higher eukaryotes, thioredoxin reductases contain the rare amino acid selenocysteine at the active site. The mitochondrial enzyme from Caenorhabditis elegans, however, contains a cysteine residue in place of selenocysteine. The mitochondrial C. elegans thioredoxin reductase was cloned from an expressed sequence tag and then produced in Escherichia coli as an intein-fusion protein. The purified recombinant enzyme has a k {sub cat} of 610 min{sup -1} and a K {sub m} of 610 {mu}M using E. coli thioredoxin as substrate. The reported k {sub cat} is 25% of the k {sub cat} of the mammalian enzyme and is 43-fold higher than a cysteine mutant of mammalian thioredoxin reductase. The enzyme would reduce selenocysteine, but not hydrogen peroxide or insulin. The flanking glycine residues of the GCCG motif were mutated to serine. The mutants improved substrate binding, but decreased the catalytic rate.

  14. Effect of MTHFR, TGF?1, and TNFB polymorphisms on osteoporosis in rheumatoid arthritis patients.

    PubMed

    Saad, Mohamed N; Mabrouk, Mai S; Eldeib, Ayman M; Shaker, Olfat G

    2015-09-01

    Diseases of the immune and the skeletal systems should be studied together for the deep interaction between them. Many studies consider osteoporosis (OP) as a risk factor for the prediction of disease progression in rheumatoid arthritis (RA). The aim of this research is to study the effect of four single nucleotide polymorphisms (SNPs) on RA patients with and without OP. The examined SNPs (MTHFR (C677T, and A1298C), TGF?1 (T869C), and TNFB (A252G)) were tested by genotyping 17 RA patients with OP and 72 RA patients without OP. Associations were tested using four models (multiplicative, dominant, recessive, and co-dominant). The studied SNPs were not significantly associated with the risk of OP in RA. MTHFR, TGF?1, and TNFB polymorphisms don't appear to be clinically useful genetic markers for predicting RA severity in Egyptian women population. PMID:25981594

  15. DNA methylation in schizophrenia subjects: gender and MTHFR 677C/T genotype differences

    PubMed Central

    Burghardt, Kyle J; Pilsner, J Richard; Bly, Michael J; Ellingrod, Vicki L

    2012-01-01

    Aim In schizophrenia, metabolic syndrome incidence is double that of the general population, with women having a higher incidence. Pharmacogenetically regulated folic acid may be related to this risk. DNA methylation and metabolic syndrome within this group has not been previously studied. Methods Metabolic syndrome was evaluated with fasting laboratory measurements, and dietary and lifestyle assessments. Methylation analysis used a peripheral sample for the LINE-1 assay. DNA was also genotyped for MTHFR 677C/T. Results This analysis included 133 subjects. We found a significant relationship between LINE-1 methylation, and an interaction between MTHFR and gender, controlling for serum folate (p = 0.008). Females with the 677TT genotype had the lowest methylation (56%) compared with the other groups (75%). Conclusion TT genotype females had the lowest methylation, which may explain metabolic syndrome gender differences in schizophrenia. Folate supplementation may be a suggested intervention within schizophrenia; however, additional work is required. PMID:22690662

  16. Homocysteine, MTHFR and risk of venous thrombosis: a meta-analysis of published epidemiological studies

    Microsoft Academic Search

    M. den Heijer; S. Lewington; R. Clarke

    2005-01-01

    CONTEXT: It has been suggested that elevated total plasma homocysteine levels are associated with the risk of venous thrombosis. OBJECTIVE: To assess the relationship of homocysteine and the MTHFR 677TT genotype and the risk of venous thrombosis by conducting a meta-analysis of all relevant studies. DATA SOURCES AND SELECTION: Studies (case-control or nested case-control) were identified by searches of electronic

  17. Evaluation of Factor V G1691A, prothrombin G20210A, Factor XIII V34L, MTHFR A1298C, MTHFR C677T and PAI-1 4G/5G genotype frequencies of patients subjected to cardiovascular disease (CVD) panel in south-east region of Turkey.

    PubMed

    Oztuzcu, Serdar; Ergun, Sercan; Ula?l?, Mustafa; Nacarkahya, Gülper; I?ci, Yusuf Ziya; I?ci, Mehri; Bayraktar, Recep; Tamer, Ali; Çakmak, Ecir Ali; Arslan, Ahmet

    2014-06-01

    Cardiovascular disease (CVD) risk factors, such as arterial hypertension, obesity, dyslipidemia or diabetes mellitus, as well as CVDs, including myocardial infarction, coronary artery disease or stroke, are the most prevalent diseases and account for the major causes of death worldwide. In the present study, 4,709 unrelated patients subjected to CVD panel in south-east part of Turkey between the years 2010 and 2013 were enrolled and DNA was isolated from the blood samples of these patients. Mutation analyses were conducted using the real-time polymerase chain reaction method to screen six common mutations (Factor V G1691A, PT G20210A, Factor XIII V34L, MTHFR A1298C and C677T and PAI-1 -675 4G/5G) found in CVD panel. The prevalence of these mutations were 0.57, 0.25, 2.61, 13.78, 9.34 and 24.27 % in homozygous form, respectively. Similarly, the mutation percent of them in heterozygous form were 7.43, 3.44, 24.91, 44.94, 41.09 and 45.66%, respectively. No mutation was detected in 92 (1.95%) patients in total. Because of the fact that this is the first study to screen six common mutations in CVD panel in south-east region of Turkey, it has a considerable value on the diagnosis and treatment of these diseases. Upon the results of the present and previous studied a careful examination for these genetic variants should be carried out in thrombophilia screening programs, particularly in Turkish population. PMID:24532105

  18. MTHFR C677T polymorphism interaction with heavy alcohol consumption increases head and neck carcinoma risk

    PubMed Central

    Zhuo, Xianlu; Song, Jue; Li, Dairong; Wu, Yongzhong; Zhou, Qi

    2015-01-01

    MTHFR C677T polymorphism has been indicated to be a risk factor for cancers, but its association with head and neck cancer (HNC) risk remains inconclusive. In the present study, we aimed to get a more precise estimation by performing a quantitative meta-analysis. Published papers up to Jun 2014 was searched and screened. Necessary information was rigorously extracted for data pooling and analyzing, and then, subgroup analyses on ethnicity, source of controls, sample size, tumor type, smoking and drinking status were also carried out. As a result, twenty-three case-control studies including 14298 subjects were included. The overall data failed to reveal a significant association between MTHFR C677T polymorphism and HNC risk (homozygote comparison model: OR?=?1.16; 95%CI?=?0.93-1.45; dominant model: OR?=?1.05; 95%CI?=?0.90-1.21; recessive model: OR?=?1.14; 95%CI?=?0.93-1.38). However, in the subgroup analysis about drinking status, increase risk was shown in the heavy drinking subgroup (TT vs CC: OR?=?3.11; 95%CI?=?1.52-3.02). In conclusion, the results of the present study suggest that Homozygous TT alleles of MTHFR C677T polymorphism might be a risk factor for HNC among individuals who have a heavy drinking history. Further studies are needed to get a more definitive conclusion. PMID:26035704

  19. Relationship of MTHFR and NQO1 Pharmacogenetics and Chemotherapy Clinical Outcomes in Breast Cancer Patients.

    PubMed

    Chaturvedi, Pankaj; Tulsyan, Sonam; Agarwal, Gaurav; Lal, Punita; Agrawal, Sushma; Mittal, Rama D; Mittal, Balraj

    2015-08-01

    The study aimed at evaluating the influence of MTHFR 677C>T and NQO1 609C>T polymorphisms in toxicity and response to chemotherapy in breast cancer patients. These two genes are involved in the folate homeostasis and bioactivation of chemotherapeutic drugs, respectively. In this study, 243 patients treated with FEC/FAC/methotrexate chemotherapy regimen were recruited and followed up for toxicity (NCI-CTCAE ver. 3). While out of 243 patients, 115 patients who received neo-adjuvant chemotherapy (NACT) were followed for treatment response. Genetic analysis of MTHFR 677C>T and NQO1 609C>T was done by PCR-restriction fragment length polymorphism. We found significant association of variant genotype (TT) of NQO1 609C>T with grade 2-4 toxicity [OR 0.33 (0.13-0.88), P = 0.027] and with grade 2-4 anemia [OR 0.34 (0.12-0.95), P = 0.041]. However, no association of MTHFR 677C>T was seen with either response to NACT or drug-induced toxicity. The study provides useful information for prediction of clinical outcomes in breast cancer patients in terms of NQO1 609C>T by evaluating its association with chemotherapy-induced toxicity. PMID:26014925

  20. MTHFR C677T polymorphism interaction with heavy alcohol consumption increases head and neck carcinoma risk.

    PubMed

    Zhuo, Xianlu; Song, Jue; Li, Dairong; Wu, Yongzhong; Zhou, Qi

    2015-01-01

    MTHFR C677T polymorphism has been indicated to be a risk factor for cancers, but its association with head and neck cancer (HNC) risk remains inconclusive. In the present study, we aimed to get a more precise estimation by performing a quantitative meta-analysis. Published papers up to Jun 2014 was searched and screened. Necessary information was rigorously extracted for data pooling and analyzing, and then, subgroup analyses on ethnicity, source of controls, sample size, tumor type, smoking and drinking status were also carried out. As a result, twenty-three case-control studies including 14298 subjects were included. The overall data failed to reveal a significant association between MTHFR C677T polymorphism and HNC risk (homozygote comparison model: OR?=?1.16; 95%CI?=?0.93-1.45; dominant model: OR?=?1.05; 95%CI?=?0.90-1.21; recessive model: OR?=?1.14; 95%CI?=?0.93-1.38). However, in the subgroup analysis about drinking status, increase risk was shown in the heavy drinking subgroup (TT vs CC: OR?=?3.11; 95%CI?=?1.52-3.02). In conclusion, the results of the present study suggest that Homozygous TT alleles of MTHFR C677T polymorphism might be a risk factor for HNC among individuals who have a heavy drinking history. Further studies are needed to get a more definitive conclusion. PMID:26035704

  1. Association of methylenetetrahydrofolate reductase C677T polymorphism and serum lipid levels in the Guangxi Bai Ku Yao and Han populations

    PubMed Central

    2010-01-01

    Background The association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and serum lipid profiles is still controversial in diverse ethnics. Bai Ku Yao is an isolated subgroup of the Yao minority in China. The aim of the present study was to eveluate the association of MTHFR C677T polymorphism and several environmental factors with serum lipid levels in the Guangxi Bai Ku Yao and Han populations. Methods A total of 780 subjects of Bai Ku Yao and 686 participants of Han Chinese were randomly selected from our previous stratified randomized cluster samples. Genotyping of the MTHFR C677T was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing. Results The levels of serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein (Apo) AI and ApoB were lower in Bai Ku Yao than in Han (P < 0.05-0.001). The frequency of C and T alleles was 77.4% and 22.6% in Bai Ku Yao, and 60.9% and 39.1% in Han (P < 0.001); respectively. The frequency of CC, CT and TT genotypes was 58.7%, 37.3% and 4.0% in Bai Ku Yao, and 32.6%, 56.4% and 11.0% in Han (P < 0.001); respectively. The levels of TC and LDL-C in both ethnic groups were significant differences among the three genotypes (P < 0.05-0.01). The T allele carriers had higher serum TC and LDL-C levels than the T allele noncarriers. The levels of ApoB in Han were significant differences among the three genotypes (P < 0.05). The T allele carriers had higher serum ApoB levels as compared with the T allele noncarriers. The levels of TC, TG and LDL-C in Bai Ku Yao were correlated with genotypes (P < 0.05-0.001), whereas the levels of LDL-C in Han were associated with genotypes (P < 0.001). Serum lipid parameters were also correlated with sex, age, body mass index, alcohol consumption, cigarette smoking, and blood pressure in the both ethnic groups. Conclusions The differences in serum TC, TG, LDL-C and ApoB levels between the two ethnic groups might partly result from different genotypic and allelic frequencies of the MTHFR C677T or different MTHFR gene-enviromental interactions. PMID:20977771

  2. The aldo-keto reductases (AKRs): Overview.

    PubMed

    Penning, Trevor M

    2015-06-01

    The aldo-keto reductase (AKR) protein superfamily contains >190 members that fall into 16 families and are found in all phyla. These enzymes reduce carbonyl substrates such as: sugar aldehydes; keto-steroids, keto-prostaglandins, retinals, quinones, and lipid peroxidation by-products. Exceptions include the reduction of steroid double bonds catalyzed by AKR1D enzymes (5?-reductases); and the oxidation of proximate carcinogen trans-dihydrodiol polycyclic aromatic hydrocarbons; while the ?-subunits of potassium gated ion channels (AKR6 family) control Kv channel opening. AKRs are usually 37kDa monomers, have an (?/?)8-barrel motif, display large loops at the back of the barrel which govern substrate specificity, and have a conserved cofactor binding domain. AKRs catalyze an ordered bi bi kinetic mechanism in which NAD(P)H cofactor binds first and leaves last. In enzymes that favor NADPH, the rate of release of NADP(+) is governed by a slow isomerization step which places an upper limit on kcat. AKRs retain a conserved catalytic tetrad consisting of Tyr55, Asp50, Lys84, and His117 (AKR1C9 numbering). There is conservation of the catalytic mechanism with short-chain dehydrogenases/reductases (SDRs) even though they show different protein folds. There are 15 human AKRs of these AKR1B1, AKR1C1-1C3, AKR1D1, and AKR1B10 have been implicated in diabetic complications, steroid hormone dependent malignancies, bile acid deficiency and defects in retinoic acid signaling, respectively. Inhibitor programs exist world-wide to target each of these enzymes to treat the aforementioned disorders. Inherited mutations in AKR1C and AKR1D1 enzymes are implicated in defects in the development of male genitalia and bile acid deficiency, respectively, and occur in evolutionarily conserved amino acids. The human AKRs have a large number of nsSNPs and splice variants, but in many instances functional genomics is lacking. AKRs and their variants are now poised to be interrogated using modern genomic and informatics approaches to determine their association with human health and disease. PMID:25304492

  3. TPMT and MTHFR genotype is not associated with altered risk of thioguanine-related sinusoidal obstruction syndrome in pediatric acute lymphoblastic leukemia: a report from the Children's Oncology Group.

    PubMed

    Wray, Lisa; Vujkovic, Marijana; McWilliams, Thomas; Cannon, Shannon; Devidas, Meenakshi; Stork, Linda; Aplenc, Richard

    2014-11-01

    Sinusoidal obstruction syndrome is a complication of therapy for pediatric ALL and may be modified by thiopurine methyltransferase activity as well as by MTHFR genotype. We assessed TPMT *3A, *3B, *3C, and MTHFR C677T and A1298C germline genetic polymorphisms among 351 patients enrolled in the thioguanine treatment arm of CCG-1952 clinical trial. TPMT and MTHFR C677T genotypes were not associated with SOS risk. The combination of MTHFR and TPMT variant genotypes was not associated with SOS risk. These suggest that germline genetic variation in TPMT and MTHFR do not significantly alter SOS risk in patients exposed to thioguanine. PMID:24737678

  4. Quantification of key red blood cell folates from subjects with defined MTHFR 677C>T genotypes using stable isotope dilution liquid chromatography/mass spectrometry

    PubMed Central

    Huang, Yuehua; Khartulyari, Stefanie; Morales, Megan E.; Stanislawska-Sachadyn, Anna; Von Feldt, Joan M.; Whitehead, Alexander S.; Blair, Ian A.

    2014-01-01

    Red blood cell (RBC) folate levels are established at the time of erythropoiesis and therefore provide a surrogate biomarker for the average folate status of an individual over the preceding four months. Folates are present as folylpolyglutamates, highly polar molecules that cannot be secreted from the RBCs, and must be converted into their monoglutamate forms prior to analysis. This was accomplished using an individual’s plasma pteroylpolyglutamate hydrolase by lysing the RBCs in whole blood at pH 5 in the presence of ascorbic acid. Quantitative conversion of formylated tetrahydrofolate derivatives into the stable 5,10-methenyltetrahydrofolate (5,10-MTHF) form was conducted at pH 1.5 in the presence of [13C5]-5-formyltetrahydrofolate. The resulting [13C5]-5,10-MTHF was then used as an internal standard for the formylated forms of tetrahydrofolate that had been converted into 5,10-MTHF as well any 5,10-MTHF that had been present in the original sample. A stable isotope dilution liquid chromatography-multiple reaction monitoring/mass spectrometry method was validated and then used for the accurate and precise quantification of RBC folic acid, 5-methyltetrahydrofolate (5-MTHF), tetrahydrofolate (THF), and 5,10-MTHF. The method was sensitive and robust and was used to assess the relationship between different methylenetetrahydrofolate reductase (MTHFR) 677C>T genotypes and RBC folate phenotypes. Four distinct RBC folate phenotypes could be identified. These were classified according to the relative amounts of individual RBC folates as type I (5-MTHF >95%; THF <5%; 5,10-MTHF <5%), type II (5-MTHF <95%; THF 5% to 20%; 5,10-MTHF <5%), type III (5-MTHF >55%; THF >20%; 5,10-MTHF >5%), and type IV (5-MTHF <55%; THF >20%; 5,10-MTHF >5%). PMID:18634122

  5. The prenyltransferase UBIAD1 is the target of geranylgeraniol in degradation of HMG CoA reductase

    PubMed Central

    Schumacher, Marc M; Elsabrouty, Rania; Seemann, Joachim; Jo, Youngah; DeBose-Boyd, Russell A

    2015-01-01

    Schnyder corneal dystrophy (SCD) is an autosomal dominant disorder in humans characterized by abnormal accumulation of cholesterol in the cornea. SCD-associated mutations have been identified in the gene encoding UBIAD1, a prenyltransferase that synthesizes vitamin K2. Here, we show that sterols stimulate binding of UBIAD1 to the cholesterol biosynthetic enzyme HMG CoA reductase, which is subject to sterol-accelerated, endoplasmic reticulum (ER)-associated degradation augmented by the nonsterol isoprenoid geranylgeraniol through an unknown mechanism. Geranylgeraniol inhibits binding of UBIAD1 to reductase, allowing its degradation and promoting transport of UBIAD1 from the ER to the Golgi. CRISPR-CAS9-mediated knockout of UBIAD1 relieves the geranylgeraniol requirement for reductase degradation. SCD-associated mutations in UBIAD1 block its displacement from reductase in the presence of geranylgeraniol, thereby preventing degradation of reductase. The current results identify UBIAD1 as the elusive target of geranylgeraniol in reductase degradation, the inhibition of which may contribute to accumulation of cholesterol in SCD. DOI: http://dx.doi.org/10.7554/eLife.05560.001 PMID:25742604

  6. All in the family: aldose reductase and closely related aldo-keto reductases.

    PubMed

    Petrash, J M

    2004-04-01

    Aldose reductase catalyzes the first step in the polyol pathway and is thought to be involved in the pathogenesis of diabetic complications. In addition to polyol synthesis, aldose reductase may have multiple other activities that intersect with signal processing and oxidative defense mechanisms. Multiple aldose reductase-like proteins have been discovered to have structures and catalytic properties that broadly overlap those of aldose reductase. This chapter will summarize new insights into properties and functions of aldose reductase and closely related members of the aldo-keto reductase enzyme superfamily. PMID:15094999

  7. Methylenetetrahydrofolate reductase gene polymorphisms and the risk of anencephaly in Mexico.

    PubMed

    Muñoz, Julia Blanco; Lacasaña, Marina; Cavazos, Ricardo García; Borja-Aburto, Victor Hugo; Galavíz-Hernández, Carlos; Garduño, Clemente Aguilar

    2007-06-01

    The precise etiology of neural tube defects (NTDs) is not known. There is some evidence that mutations in MTHFR gene provide susceptibility to NTDs in some populations; however, other studies have not found this association. One of the problems with previous studies is that they treat NTDs as a homogeneous group, when specific defects could have different etiologies. We conducted a case-control study specifically for anencephaly, based on the Mexican Epidemiological Surveillance System of Neural Tube Defects to evaluate its association with maternal MTHFR 677C > T and 1298A > C polymorphisms, in three states with high frequencies of NTDs: Puebla, Estado de México and Guerrero. We interviewed and collected blood samples from 118 case mothers and 112 control mothers. The questionnaire included information on their reproductive history, socioeconomic characteristics, prenatal care, tobacco and alcohol use, presence of chronic diseases, acute illnesses and fever, consumption of multivitamins and drugs during the periconceptional period. After adjusting for potential confounders, the risk from the mutated homozygous mothers (677TT genotype) was significantly higher than that from mothers with 677CC genotype (OR 3.16, 95% CI 1.29-7.73); in the case of the heterozygous mothers, an increased risk of anencephaly was observed, even though this was not statistically significant (OR 1.81 95% CI 0.78-4.25). The association found between maternal 677TT genotype and anencephaly and the elevated presence of the 677T allele among Mexican women of fertile age urges intensifying folic acid supplementation which has proved to modify this genetic risk in other populations. PMID:17439956

  8. Regulatory changes in the formation of chromosomal dihydrofolate reductase causing resistance to trimethoprim.

    PubMed Central

    Flensburg, J; Sköld, O

    1984-01-01

    High resistance to trimethoprim mediated by the several hundredfold overproduction of the drug target enzyme, dihyrofolate reductase, in a clinically isolated Escherichia coli strain, 1810, was cloned onto several vector plasmids and seemed to be comprised of a single dihydrofolate reductase gene, which by DNA-DNA hybridization and restriction enzyme digestion mapping was very similar to the corresponding gene of E. coli K-12. Determination of mRNA formation in the originally isolated resistant strain and strains with cloned trimethoprim resistance determinant demonstrated an about 15-fold increase in production of dihydrofolate reductase mRNA compared with that in E. coli K-12. This was explained by the occurrence of a promoter up mutation in the resistant isolate accompanied by changes in the restriction enzyme digestion pattern found by comparison with the corresponding pattern from E. coli K-12. Images PMID:6330028

  9. Evidence that biliverdin-IX beta reductase and flavin reductase are identical.

    PubMed Central

    Shalloe, F; Elliott, G; Ennis, O; Mantle, T J

    1996-01-01

    A search of the database shows that human biliverdin-IX beta reductase and flavin reductase are identical. We have isolated flavin reductase from bovine erythrocytes and show that the activity co-elutes with biliverdin-IX beta reductase. Preparations of the enzyme that are electrophoretically homogeneous exhibit both flavin reductase and biliverdin-IX beta reductase activities; however, they are not capable of catalysing the reduction of biliverdin-IX alpha. Although there is little obvious sequence identity between biliverdin-IX alpha reductase (BVR-A) and biliverdin-IX beta reductase (BVR-B), they do show weak immunological cross-reactivity. Both enzymes bind to 2',5'-ADP-Sepharose. PMID:8687377

  10. Nitrate reductase from Rhodopseudomonas sphaeroides.

    PubMed

    Kerber, N L; Cardenas, J

    1982-06-01

    The facultative phototroph Rhodopseudomonas sphaeroides DSM158 was incapable of either assimilating or dissimilating nitrate, although the organism could reduce it enzymatically to nitrite either anaerobically in the light or aerobically in the dark. Reduction of nitrate was mediated by a nitrate reductase bound to chromatophores that could be easily solubilized and functioned with chemically reduced viologens or photochemically reduced flavins as electron donors. The enzyme was solubilized, and some of its kinetic and molecular parameters were determined. It seemed to be nonadaptive, ammonia did not repress its synthesis, and its activity underwent a rapid decline when the cells entered the stationary growth phase. Studies with inhibitors and with metal antagonists indicated that molybdenum and possibly iron participate in the enzymatic reduction of nitrate. The conjectural significance of this nitrate reductase in phototrophic bacteria is discussed. PMID:6978883

  11. Nitrate reductase from Rhodopseudomonas sphaeroides.

    PubMed Central

    Kerber, N L; Cardenas, J

    1982-01-01

    The facultative phototroph Rhodopseudomonas sphaeroides DSM158 was incapable of either assimilating or dissimilating nitrate, although the organism could reduce it enzymatically to nitrite either anaerobically in the light or aerobically in the dark. Reduction of nitrate was mediated by a nitrate reductase bound to chromatophores that could be easily solubilized and functioned with chemically reduced viologens or photochemically reduced flavins as electron donors. The enzyme was solubilized, and some of its kinetic and molecular parameters were determined. It seemed to be nonadaptive, ammonia did not repress its synthesis, and its activity underwent a rapid decline when the cells entered the stationary growth phase. Studies with inhibitors and with metal antagonists indicated that molybdenum and possibly iron participate in the enzymatic reduction of nitrate. The conjectural significance of this nitrate reductase in phototrophic bacteria is discussed. PMID:6978883

  12. Effect of Mutation on Enzyme Motion in Dihydrofolate James B. Watney, Pratul K. Agarwal, and Sharon Hammes-Schiffer*

    E-print Network

    Hammes-Schiffer, Sharon

    Effect of Mutation on Enzyme Motion in Dihydrofolate Reductase James B. Watney, Pratul K. Agarwal- folate reductase enzyme are presented. Although residue 121 is on the exterior of the enzyme for the mutant than for the wild-type enzyme by an amount that is consistent with the experimentally observed

  13. Major gene evidence after MTHFR-segregation analysis of serum homocysteine in families of patients undergoing coronary arteriography

    Microsoft Academic Search

    Sun Ha Jee; Kyung Soon Song; Won Heum Shim; Hyun Kyung Kim; Il Suh; Jung Yong Park; So Won; Terri H. Beaty

    2002-01-01

    Elevated levels of homocysteine is a risk factor for coronary artery disease. Polymorphic alleles in the MTHFR genes that cause recessively inherited increased homocysteine level can explain only a small proportion of the observed variation in homocysteine level. To investigate additional genetic influences, we examined environmental, familial, and genetic influences on serum homocysteine levels in 661 family members of 112

  14. Association between MTHFR C677T polymorphism and congenital heart disease. A family-based meta-analysis.

    PubMed

    Li, Z; Jun, Y; Zhong-Bao, R; Jie, L; Jian-Ming, L

    2015-04-01

    Congenital heart disease (CHD) is the most common type of birth defect. It is suspected that polymorphisms in folate metabolism are associated with an increased risk of CHD, but the conclusion remains unclear. Studies have reported that the MTHFR C677T polymorphism was associated with the development of structural congenital heart malformations. The objective of this study was to conduct a meta-analysis of available studies to identify common polymorphisms in the MTHFR gene in children with CHD and their mothers and to test for an association between genotype and disease. In all, 19 eligible studies comprising 4,219 cases and 20,123 controls were included in this meta-analysis. A significant association was found between the MTHFR C677T polymorphism and CHD risk (OR: 1.26; 95?% CI =?1.06-1.51; p?=?0.009) with no strong evidence of heterogeneity (I(2)?=?39?%) in the fetal analysis. In the maternal analysis, the MTHFR C677T polymorphism was significantly associated with CHD risk (OR =?1.52; 95?% CI =? 1.09-2.11; p?=?0.01) with significant heterogeneity (I(2)?=?63?%). PMID:25256053

  15. Role of aldo-keto reductase family 1 (AKR1) enzymes in human steroid metabolism.

    PubMed

    Rižner, Tea Lanišnik; Penning, Trevor M

    2014-01-01

    Human aldo-keto reductases AKR1C1-AKR1C4 and AKR1D1 play essential roles in the metabolism of all steroid hormones, the biosynthesis of neurosteroids and bile acids, the metabolism of conjugated steroids, and synthetic therapeutic steroids. These enzymes catalyze NADPH dependent reductions at the C3, C5, C17 and C20 positions on the steroid nucleus and side-chain. AKR1C1-AKR1C4 act as 3-keto, 17-keto and 20-ketosteroid reductases to varying extents, while AKR1D1 acts as the sole ?(4)-3-ketosteroid-5?-reductase (steroid 5?-reductase) in humans. AKR1 enzymes control the concentrations of active ligands for nuclear receptors and control their ligand occupancy and trans-activation, they also regulate the amount of neurosteroids that can modulate the activity of GABAA and NMDA receptors. As such they are involved in the pre-receptor regulation of nuclear and membrane bound receptors. Altered expression of individual AKR1C genes is related to development of prostate, breast, and endometrial cancer. Mutations in AKR1C1 and AKR1C4 are responsible for sexual development dysgenesis and mutations in AKR1D1 are causative in bile-acid deficiency. PMID:24189185

  16. Structural features of the aldose reductase and aldehyde reductase inhibitor-binding sites.

    PubMed

    El-Kabbani, O; Wilson, D K; Petrash, M; Quiocho, F A

    1998-09-29

    The three-dimensional structures of aldose reductase and aldehyde reductase, members of the aldo-keto reductase superfamily, are composed of similar alpha/beta TIM-barrels. However, examination of the structures reveals that the inhibitor-binding site of aldose reductase differs from that of aldehyde reductase due to the participation of non-conserved residues in its formation. This information will be useful in the design of inhibitors to prevent or delay diabetic retinopathy. A review of the structures of the inhibitor-binding sites is presented. PMID:9756955

  17. Cloning and Expression Analysis of Dihydroflavonol 4Reductase Gene in Brassica juncea

    Microsoft Academic Search

    Ming-Li YAN; Xian-Jun LIU; Zhong-Song LIU; Chun-Yun GUAN; Mou-Zhi YUAN; Xing-Hua XIONG

    2008-01-01

    Dihydroflavonol 4-reductase (DFR) gene is a key gene of proanthocyanidins biosynthesis pathway in seed coat of Arabidopsis thaliana. The mutation of this gene brings about a transparent testa. To study molecular mechanism of seed coat color in Brassica, DFR gene was cloned from B. juncea using homology-based clone strategy. The cloned gene 1,612 bp in length contains 5 introns. The

  18. Phenotypic classification of male pseudohermaphroditism due to steroid 5{alpha}-reductase 2 deficiency

    SciTech Connect

    Sinnecker, G.H.G; Hiort, O.; Kruse, K.; Dibbelt, L. [Medical Univ. of Luebeck (Germany)] [and others] [Medical Univ. of Luebeck (Germany); and others

    1996-05-03

    Conversion of testosterone (T) to dihydrotestosterone (DHT) in genital tissue is catalysed by the enzyme 5{alpha}-reductase 2, which is encoded by the SRD5A2 gene. The potent androgen DHT is required for full masculinization of the external genitalia. Mutations of the SRD5A2 gene inhibit enzyme activity, diminish DHT formation, and hence cause masculinization defects of varying degree. The classical syndrome, formerly described as pseudovaginal perineoscrotal hypospadias, is characterized by a predominantly female phenotype at birth and significant virilization without gynecomastia at puberty. We investigated nine patients with steroid 5{alpha}-reductase 2 deficiency (SRD). T/DHT-ratios were highly increased in the classical syndrome, but variable in the less severe affected patients. Mutations in the SRD5A2 gene had been characterized using PCR-SSCP analysis and direct DNA sequencing. A small deletion was encountered in two patients, while all other patients had single base mutations which result in amino acid substitutions. We conclude that phenotypes may vary widely in patients with SRD5A2 gene mutations spanning the whole range from completely female to normal male without distinctive clinical signs of the disease. Hence, steroid 5{alpha}-reductase deficiency should be considered not only in sex reversed patients with female or ambiguous phenotypes, but also in those with mild symptoms of undermasculinization as encountered in patients with hypospadias and/or micropenis. A classification based on the severity of the masculinization defect may be used for correlation of phenotypes with enzyme activities and genotypes, and for comparisons of phenotypes between different patients as the basis for clinical decisions to be made in patients with pseudohermaphroditism due to steroid 5{alpha}-reductase 2 deficiency. 22 refs., 2 figs., 2 tabs.

  19. Studies on nitrite reductase in barley

    Microsoft Academic Search

    W. F. Bourne; B. J. Miflin

    1973-01-01

    Nitrite reductase from barley seedlings was purified 50–60 fold by ammonium sulphate precipitation and gel filtration. No differences were established in the characteristics of nitrite reductases isolated in this way from either leaf or root tissues. The root enzyme accepted electrons from reduced methyl viologen, ferredoxin, or an unidentified endogenous cofactor. Enzyme activity in both tissues was markedly increased by

  20. Meta-analysis of MTHFR 677C->T polymorphism and coronary heart disease: does totality of evidence support causal role for homocysteine and preventive potential of folate?

    Microsoft Academic Search

    Sarah J Lewis; Shah Ebrahim; George Davey Smith

    2005-01-01

    Objectives To investigate the association between the MTHFR 677C?T polymorphism and coronary heart disease, assessing small study bias and heterogeneity between studies. Data sources Medline and Embase citation searches between January 2001 and August 2004; no language restrictions. Study selection Case-control and prospective studies of association between MTHFR 677C?T variant and myocardial infarction, coronary artery occlusion, or both; 80 studies

  1. Do mutator mutations fuel tumorigenesis?

    PubMed Central

    Fox, Edward J.; Prindle, Marc J.

    2014-01-01

    The mutator phenotype hypothesis proposes that the mutation rate of normal cells is insufficient to account for the large number of mutations found in human cancers. Consequently, human tumors exhibit an elevated mutation rate that increases the likelihood of a tumor acquiring advantageous mutations. The hypothesis predicts that tumors are composed of cells harboring hundreds of thousands of mutations, as opposed to a small number of specific driver mutations, and that malignant cells within a tumor therefore constitute a highly heterogeneous population. As a result, drugs targeting specific mutated driver genes or even pathways of mutated driver genes will have only limited anticancer potential. In addition, because the tumor is composed of such a diverse cell population, tumor cells harboring drug-resistant mutations will exist prior to the administration of any chemotherapeutic agent. We present recent evidence in support of the mutator phenotype hypothesis, major arguments against this concept, and discuss the clinical consequences of tumor evolution fueled by an elevated mutation rate. We also consider the therapeutic possibility of altering the rate of mutation accumulation. Most significantly, we contend that there is a need to fundamentally reconsider current approaches to personalized cancer therapy. We propose that targeting cellular pathways that alter the rate of mutation accumulation in tumors will ultimately prove more effective than attempting to identify and target mutant driver genes or driver pathways. PMID:23592419

  2. The K(C) channel in the cbb3-type respiratory oxygen reductase from Rhodobacter capsulatus is required for both chemical and pumped protons.

    PubMed

    Y?ld?z, Gülgez Gökçe; Gennis, Robert B; Daldal, Fevzi; Öztürk, Mehmet

    2014-05-01

    The heme-copper superfamily of proton-pumping respiratory oxygen reductases are classified into three families (A, B, and C families) based on structural and phylogenetic analyses. Most studies have focused on the A family, which includes the eukaryotic mitochondrial cytochrome c oxidase as well as many bacterial homologues. Members of the C family, also called the cbb3-type oxygen reductases, are found only in prokaryotes and are of particular interest because of their presence in a number of human pathogens. All of the heme-copper oxygen reductases require proton-conducting channels to convey chemical protons to the active site for water formation and to convey pumped protons across the membrane. Previous work indicated that there is only one proton-conducting input channel (the K(C) channel) present in the cbb3-type oxygen reductases, which, if correct, must be utilized by both chemical protons and pumped protons. In this work, the effects of mutations in the K(C) channel of the cbb3-type oxygen reductase from Rhodobacter capsulatus were investigated by expressing the mutants in a strain lacking other respiratory oxygen reductases. Proton pumping was evaluated by using intact cells, and catalytic oxygen reductase activity was measured in isolated membranes. Two mutations, N346M and Y374F, severely reduced catalytic activity, presumably by blocking the chemical protons required at the active site. One mutation, T272A, resulted in a substantially lower proton-pumping stoichiometry but did not inhibit oxygen reductase activity. These are the first experimental data in support of the postulate that pumped protons are taken up from the bacterial cytoplasm through the K(C) channel. PMID:24563037

  3. Molecular simulation to investigate the cofactor specificity for pichia stipitis Xylose reductase.

    PubMed

    Xia, Xiao-Le; Cong, Shan; Weng, Xiao-Rong; Chen, Jin-Hua; Wang, Jing-Fang; Chou, Kuo-Chen

    2013-11-01

    Xylose is one of the most abundant carbohydrates in nature, and widely used to produce bioethanol via fermentation in industry. Xylulose can produce two key enzymes: xylose reductase and xylitol dehydrogenase. Owing to the disparate cofactor specificities of xylose reductase and xylitol dehydrogenase, intracellular redox imbalance is detected during the xylose fermentation, resulting in low ethanol yields. To overcome this barrier, a common strategy is applied to artificially modify the cofactor specificity of xylose reductase. In this study, we utilized molecular simulation approaches to construct a 3D (three-dimensional) structural model for the NADP-dependent Pichia stipitis xylose reductase (PsXR). Based on the 3D model, the favourable binding modes for both cofactors NAD and NADP were obtained using the flexible docking procedure and molecular dynamics simulation. Structural analysis of the favourable binding modes showed that the cofactor binding site of PsXR was composed of 3 major components: a hydrophilic pocket, a hydrophobic pocket as well as a linker channel between the aforementioned two pockets. The hydrophilic pocket could recognize the nicotinamide moiety of the cofactors by hydrogen bonding networks, while the hydrophobic pocket functioned to position the adenine moiety of the cofactors by hydrophobic and ?-? stacking interactions. The linker channel contained some key residues for ligand-binding; their mutation could have impact to the specificity of PsXR. Finally, it was found that any of the two single mutations, K21A and K270N, might reverse the cofactor specificity of PsXR from major NADP- to NADdependent, which was further confirmed by the additional experiments. Our findings may provide useful insights into the cofactor specificity of PsXR, stimulating new strategies for better designing xylose reductase and improving ethanol production in industry. PMID:23521003

  4. Tetrathionate reductase of Salmonella thyphimurium: a molybdenum containing enzyme

    SciTech Connect

    Hinojosa-Leon, M.; Dubourdieu, M.; Sanchez-Crispin, J.A.; Chippaux, M.

    1986-04-29

    Use of radioactive molybdenum demonstrates that the tetrathionate reductase of Salmonella typhimurium is a molydenum containing enzyme. It is proposed that this enzyme shares with other molybdo-proteins, such as nitrate reductase, a common molybdenum containing cofactor the defect of which leads to the loss of the tetrathionate reductase and nitrate reductase activities.

  5. Alkyl Hydroperoxide Reductase Repair by Helicobacter pylori Methionine Sulfoxide Reductase

    PubMed Central

    Benoit, Stéphane L.; Bayyareddy, Krishnareddy; Mahawar, Manish; Sharp, Joshua S.

    2013-01-01

    Protein exposure to oxidants such as HOCl leads to formation of methionine sulfoxide (MetSO) residues, which can be repaired by methionine sulfoxide reductase (Msr). A Helicobacter pylori msr strain was more sensitive to HOCl-mediated killing than the parent. Because of its abundance in H. pylori and its high methionine content, alkyl hydroperoxide reductase C (AhpC) was hypothesized to be prone to methionine oxidation. AhpC was expressed as a recombinant protein in Escherichia coli. AhpC activity was abolished by HOCl, while all six methionine residues of the enzyme were fully to partially oxidized. Upon incubation with a Msr repair mixture, AhpC activity was restored to nonoxidized levels and the MetSO residues were repaired to methionine, albeit to different degrees. The two most highly oxidized and then Msr-repaired methionine residues in AhpC, Met101 and Met133, were replaced with isoleucine residues by site-directed mutagenesis, either individually or together. E. coli cells expressing variant versions were more sensitive to t-butyl hydroperoxide than cells expressing native protein, and purified AhpC variant proteins had 5% to 39% of the native enzyme activity. Variant proteins were still able to oligomerize like the native version, and circular dichroism (CD) spectra of variant proteins revealed no significant change in AhpC conformation, indicating that the loss of activity in these variants was not related to major structural alterations. Our results suggest that both Met101 and Met133 residues are important for AhpC catalytic activity and that their integrity relies on the presence of a functional Msr. PMID:24097943

  6. Alkyl hydroperoxide reductase repair by Helicobacter pylori methionine sulfoxide reductase.

    PubMed

    Benoit, Stéphane L; Bayyareddy, Krishnareddy; Mahawar, Manish; Sharp, Joshua S; Maier, Robert J

    2013-12-01

    Protein exposure to oxidants such as HOCl leads to formation of methionine sulfoxide (MetSO) residues, which can be repaired by methionine sulfoxide reductase (Msr). A Helicobacter pylori msr strain was more sensitive to HOCl-mediated killing than the parent. Because of its abundance in H. pylori and its high methionine content, alkyl hydroperoxide reductase C (AhpC) was hypothesized to be prone to methionine oxidation. AhpC was expressed as a recombinant protein in Escherichia coli. AhpC activity was abolished by HOCl, while all six methionine residues of the enzyme were fully to partially oxidized. Upon incubation with a Msr repair mixture, AhpC activity was restored to nonoxidized levels and the MetSO residues were repaired to methionine, albeit to different degrees. The two most highly oxidized and then Msr-repaired methionine residues in AhpC, Met101 and Met133, were replaced with isoleucine residues by site-directed mutagenesis, either individually or together. E. coli cells expressing variant versions were more sensitive to t-butyl hydroperoxide than cells expressing native protein, and purified AhpC variant proteins had 5% to 39% of the native enzyme activity. Variant proteins were still able to oligomerize like the native version, and circular dichroism (CD) spectra of variant proteins revealed no significant change in AhpC conformation, indicating that the loss of activity in these variants was not related to major structural alterations. Our results suggest that both Met101 and Met133 residues are important for AhpC catalytic activity and that their integrity relies on the presence of a functional Msr. PMID:24097943

  7. Divergent evolution of protein conformational dynamics in dihydrofolate reductase

    PubMed Central

    Bhabha, Gira; Ekiert, Damian C.; Jennewein, Madeleine; Zmasek, Christian M.; Tuttle, Lisa M.; Kroon, Gerard; Dyson, H. Jane; Godzik, Adam; Wilson, Ian A.; Wright, Peter E.

    2013-01-01

    Molecular evolution is driven by mutations, which may affect the fitness of an organism and are then subject to natural selection or genetic drift. Analysis of primary protein sequences and tertiary structures has yielded valuable insights into the evolution of protein function, but little is known about evolution of functional mechanisms, protein dynamics and conformational plasticity essential for activity. We characterized the atomic-level motions across divergent members of the dihydrofolate reductase (DHFR) family. Despite structural similarity, E. coli and human DHFRs use different dynamic mechanisms to perform the same function, and human DHFR cannot complement DHFR-deficient E. coli cells. Identification of the primary sequence determinants of flexibility in DHFRs from several species allowed us to propose a likely scenario for the evolution of functionally important DHFR dynamics, following a pattern of divergent evolution that is tuned by the cellular environment. PMID:24077226

  8. Structure of a bacterial homologue of vitamin K epoxide reductase

    SciTech Connect

    Li, Weikai; Schulman, Sol; Dutton, Rachel J.; Boyd, Dana; Beckwith, Jon; Rapoport, Tom A. (Harvard-Med); (HHMI)

    2010-03-19

    Vitamin K epoxide reductase (VKOR) generates vitamin K hydroquinone to sustain {gamma}-carboxylation of many blood coagulation factors. Here, we report the 3.6 {angstrom} crystal structure of a bacterial homologue of VKOR from Synechococcus sp. The structure shows VKOR in complex with its naturally fused redox partner, a thioredoxin-like domain, and corresponds to an arrested state of electron transfer. The catalytic core of VKOR is a four transmembrane helix bundle that surrounds a quinone, connected through an additional transmembrane segment with the periplasmic thioredoxin-like domain. We propose a pathway for how VKOR uses electrons from cysteines of newly synthesized proteins to reduce a quinone, a mechanism confirmed by in vitro reconstitution of vitamin K-dependent disulphide bridge formation. Our results have implications for the mechanism of the mammalian VKOR and explain how mutations can cause resistance to the VKOR inhibitor warfarin, the most commonly used oral anticoagulant.

  9. Imine Reductases: A Comparison of Glutamate Dehydrogenase to Ketimine Reductases in the Brain

    PubMed Central

    Jamie, Joanne F.; Cooper, Arthur J. L.

    2013-01-01

    A key intermediate in the glutamate dehydrogenase (GDH)-catalyzed reaction is an imine. Mechanistically, therefore, GDH exhibits similarities to the ketimine reductases. In the current review, we briefly discuss (a) the metabolic importance of the GDH reaction in liver and brain, (b) the mechanistic similarities between GDH and the ketimine reductases, (c) the metabolic importance of the brain ketimine reductases, and (d) the neurochemical consequences of defective ketimine reductases. Our review contains many historical references to the early work on amino acid metabolism. This work tends to be overlooked nowadays, but is crucial for a contemporary understanding of the central importance of ketimines in nitrogen and intermediary metabolism. The ketimine reductases are important enzymes linking nitrogen flow among several key amino acids, yet have been little studied. The cerebral importance of the ketimine reductases is an area of biomedical research that deserves far more attention. PMID:23314864

  10. Livedoid vasculopathy associated with combined prothrombin G20210A and factor V (Leiden) heterozygosity and MTHFR C677T homozygosity.

    PubMed

    Irani-Hakime, Noha A; Stephan, Farid; Kreidy, Raghid; Jureidini, Isabelle; Almawi, Wassim Y

    2008-08-01

    Livedoid vasculopathy (LV) is an occlusive thrombotic disease of lower extremities. A 34-year-old woman presented with 4-year history of recurrent necrotic and painful lesions with violaceous and purpuric border on both legs. Initial treatment with hydroxychloroquine, dapsone and prednisone were unsuccessful. Skin biopsy showed inflammatory infiltrate with epidermal necrosis. Prothrombin G20210A and factor V-Leiden heterozygosity, and MTHFR C677T homozygosity with hyperhomocysteinemia were confirmed. LV diagnosis was made; acetylsalicylic acid, folic acid, vitamin B12, and prednisone treatement resulted in complete healing. This is the first report on coexistence of prothrombin G20210A, factor V-Leiden, and homozygous MTHFR C677T with hyperhomocysteinemia in LV. PMID:18360788

  11. Flavoprotein Disulfide Reductases: Advances in Chemistry and Function

    Microsoft Academic Search

    Argyrides Argyrou; John S. Blanchard

    2004-01-01

    The flavoprotein disulfide reductases represent a family of enzymes that show high sequence and structural homology. They catalyze the pyridine-nucleotide-dependent reduction of a variety of substrates, including disulfide-bonded substrates (lipoamide dehydrogenase, glutathione reductase and functional homologues, thioredoxin reductase, and alkylhydroperoxide reductase), mercuric ion (mercuric ion reductase), hydrogen peroxide (NADH peroxidase), molecular oxygen (NADH oxidase), and the reductive cleavage of a

  12. Folate supplementation, MTHFR gene polymorphism and neural tube defects: a community based case control study in North India

    Microsoft Academic Search

    Roumi Deb; Jyoti Arora; Sanjenbam Yaiphaba Meitei; Sangeeta Gupta; Vanita Verma; Kallur Nava Saraswathy; Sunil Saran; Aloke Kumar Kalla

    The present study analyses the potential role of MTHFR gene polymorphism, folate supplementation and dietary pattern among\\u000a the mothers of NTD neonates and controls in heterogeneous populations of North India, with the special focus on their ethnic\\u000a labels. Results indicated significant increased risk for neural tube defects with respect to low folic acid supplementation\\u000a and vegetarian diet in univariate and

  13. Livedoid vasculopathy associated with combined prothrombin G20210A and factor V (Leiden) heterozygosity and MTHFR C677T homozygosity

    Microsoft Academic Search

    Noha A. Irani-Hakime; Farid Stephan; Raghid Kreidy; Isabelle Jureidini; Wassim Y. Almawi

    2008-01-01

    Livedoid vasculopathy (LV) is an occlusive thrombotic disease of lower extremities. A 34-year-old woman presented with 4-year\\u000a history of recurrent necrotic and painful lesions with violaceous and purpuric border on both legs. Initial treatment with\\u000a hydroxychloroquine, dapsone and prednisone were unsuccessful. Skin biopsy showed inflammatory infiltrate with epidermal necrosis.\\u000a Prothrombin G20210A and factor V-Leiden heterozygosity, and MTHFR C677T homozygosity with

  14. Neuroprotective role for carbonyl reductase?

    PubMed

    Maser, Edmund

    2006-02-24

    Oxidative stress is increasingly implicated in neurodegenerative disorders including Alzheimer's, Parkinson's, Huntington's, and Creutzfeld-Jakob diseases or amyotrophic lateral sclerosis. Reactive oxygen species seem to play a significant role in neuronal cell death in that they generate reactive aldehydes from membrane lipid peroxidation. Several neuronal diseases are associated with increased accumulation of abnormal protein adducts of reactive aldehydes, which mediate oxidative stress-linked pathological events, including cellular growth inhibition and apoptosis induction. Combining findings on neurodegeneration and oxidative stress in Drosophila with studies on the metabolic characteristics of the human enzyme carbonyl reductase (CR), it is clear now that CR has a potential physiological role for neuroprotection in humans. Several lines of evidence suggest that CR represents a significant pathway for the detoxification of reactive aldehydes derived from lipid peroxidation and that CR in humans is essential for neuronal cell survival and to confer protection against oxidative stress-induced brain degeneration. PMID:16406002

  15. Colorectal cancer and the methylenetetrahydrofolate reductase 677C -> T and methionine synthase 2756A -> G polymorphisms: a study of 2,168 case-control pairs from the JANUS cohort.

    PubMed

    Ulvik, Arve; Vollset, Stein Emil; Hansen, Svein; Gislefoss, Randi; Jellum, Egil; Ueland, Per Magne

    2004-12-01

    Polymorphisms in genes involved in the metabolism of folate and methyl groups have been implicated with risk of colorectal cancer. We evaluated the relation between the polymorphisms 677C --> T of the methylenetetrahydrofolate reductase (MTHFR) and 2756A --> G of the methionine synthase (MTR) genes and risk of colorectal cancer. From the Norwegian JANUS cohort of 309,000 subjects, 2,179 cases were identified and a similar number of controls were selected. The controls were matched for age, gender, time, and place of serum donation. Genotypes were obtained from 2,168 case-control pairs by real-time PCR of serum samples. Risk of colorectal cancer was estimated with conditional and unconditional logistic regression. Median age at diagnosis was 60 years and mean follow-up 13 years. The odds ratio for MTHFR TT versus CC was 0.73 [95% confidence interval (95% CI), 0.58-0.92] and for MTR GG versus AA was 0.65 (95% CI, 0.47-0.90). No interaction between the polymorphisms was found. Relative risk estimates were similar for men and women, and for young and old age at diagnosis. For the MTR GG genotype, risk reduction was observed at the two most distal sites (sigmoideum and rectum) only (P = 0.003). The folate marker, serum total homocysteine (tHcy), was measured in 1,837 subjects. Odds ratio for the upper versus the lower tertile of tHcy was 1.32 (95% CI, 1.04-1.68). No significant effect modification by tHcy levels was detected for either polymorphism. In summary, we found significantly reduced risk of colorectal cancer in subjects with the MTHFR 677 TT and MTR 2756 GG genotypes. No interaction between the polymorphisms, or of either polymorphism with tHcy, was detected. PMID:15598777

  16. Tissue distribution and ontogeny of steroid 5 alpha-reductase isozyme expression.

    PubMed Central

    Thigpen, A E; Silver, R I; Guileyardo, J M; Casey, M L; McConnell, J D; Russell, D W

    1993-01-01

    The synthesis of dihydrotestosterone is catalyzed by steroid 5 alpha-reductase isozymes, designated types 1 and 2. Mutation of type 2 results in male pseudohermaphroditism, in which the external genitalia are phenotypically female at birth. Two striking and unexplained features of this disorder are that external genitalia of affected males undergo virilization during puberty and that these individuals have less temporal hair regression. The tissue-specific and developmental expression patterns of the 5 alpha-reductase isozymes were investigated by immunoblotting. The type 1 isozyme is not detectable in the fetus, is transiently expressed in newborn skin and scalp, and permanently expressed in skin from the time of puberty. There was no qualitative difference in 5 alpha-reductase type 1 expression between adult balding vs. nonbalding scalp. The type 2 isozyme is transiently expressed in skin and scalp of newborns. Type 2 is the predominant isozyme detectable in fetal genital skin, male accessory sex glands, and in the prostate, including benign prostatic hyperplasia and prostate adenocarcinoma tissues. Both isozymes are expressed in the liver, but only after birth. These results are consistent with 5 alpha-reductase type 1 being responsible for virilization in type 2-deficient subjects during puberty, and suggest that the type 2 isozyme may be an initiating factor in development of male pattern baldness. Images PMID:7688765

  17. A dissimilatory nitrite reductase in Paracoccus halodenitrificans

    NASA Technical Reports Server (NTRS)

    Grant, M. A.; Hochstein, L. I.

    1984-01-01

    Paracoccus halodenitrificans produced a membrane-associated nitrite reductase. Spectrophotometric analysis showed it to be associated with a cd-cytochrome and located on the inner side of the cytoplasmic membrane. When supplied with nitrite, membrane preparations produced nitrous oxide and nitric oxide in different ratios depending on the electron donor employed. The nitrite reductase was maximally active at relatively low concentrations of sodium chloride and remained attached to the membranes at 100 mM sodium chloride.

  18. Atomic Structure of Salutaridine Reductase from the Opium Poppy (Papaver somniferum)

    SciTech Connect

    Higashi, Yasuhiro; Kutchan, Toni M.; Smith, Thomas J. (Danforth)

    2011-11-18

    The opium poppy (Papaver somniferum L.) is one of the oldest known medicinal plants. In the biosynthetic pathway for morphine and codeine, salutaridine is reduced to salutaridinol by salutaridine reductase (SalR; EC 1.1.1.248) using NADPH as coenzyme. Here, we report the atomic structure of SalR to a resolution of {approx}1.9 {angstrom} in the presence of NADPH. The core structure is highly homologous to other members of the short chain dehydrogenase/reductase family. The major difference is that the nicotinamide moiety and the substrate-binding pocket are covered by a loop (residues 265-279), on top of which lies a large 'flap'-like domain (residues 105-140). This configuration appears to be a combination of the two common structural themes found in other members of the short chain dehydrogenase/reductase family. Previous modeling studies suggested that substrate inhibition is due to mutually exclusive productive and nonproductive modes of substrate binding in the active site. This model was tested via site-directed mutagenesis, and a number of these mutations abrogated substrate inhibition. However, the atomic structure of SalR shows that these mutated residues are instead distributed over a wide area of the enzyme, and many are not in the active site. To explain how residues distal to the active site might affect catalysis, a model is presented whereby SalR may undergo significant conformational changes during catalytic turnover.

  19. Atomic structure of salutaridine reductase from the opium poppy (Papaver somniferum).

    PubMed

    Higashi, Yasuhiro; Kutchan, Toni M; Smith, Thomas J

    2011-02-25

    The opium poppy (Papaver somniferum L.) is one of the oldest known medicinal plants. In the biosynthetic pathway for morphine and codeine, salutaridine is reduced to salutaridinol by salutaridine reductase (SalR; EC 1.1.1.248) using NADPH as coenzyme. Here, we report the atomic structure of SalR to a resolution of ?1.9 ? in the presence of NADPH. The core structure is highly homologous to other members of the short chain dehydrogenase/reductase family. The major difference is that the nicotinamide moiety and the substrate-binding pocket are covered by a loop (residues 265-279), on top of which lies a large "flap"-like domain (residues 105-140). This configuration appears to be a combination of the two common structural themes found in other members of the short chain dehydrogenase/reductase family. Previous modeling studies suggested that substrate inhibition is due to mutually exclusive productive and nonproductive modes of substrate binding in the active site. This model was tested via site-directed mutagenesis, and a number of these mutations abrogated substrate inhibition. However, the atomic structure of SalR shows that these mutated residues are instead distributed over a wide area of the enzyme, and many are not in the active site. To explain how residues distal to the active site might affect catalysis, a model is presented whereby SalR may undergo significant conformational changes during catalytic turnover. PMID:21169353

  20. Structural basis of stereospecific reduction by quinuclidinone reductase

    PubMed Central

    2014-01-01

    Chiral molecule (R)-3-quinuclidinol, a valuable compound for the production of various pharmaceuticals, is efficiently synthesized from 3-quinuclidinone by using NADPH-dependent 3-quinuclidinone reductase (RrQR) from Rhodotorula rubra. Here, we report the crystal structure of RrQR and the structure-based mutational analysis. The enzyme forms a tetramer, in which the core of each protomer exhibits the ?/? Rossmann fold and contains one molecule of NADPH, whereas the characteristic substructures of a small lobe and a variable loop are localized around the substrate-binding site. Modeling and mutation analyses of the catalytic site indicated that the hydrophobicity of two residues, I167 and F212, determines the substrate-binding orientation as well as the substrate-binding affinity. Our results revealed that the characteristic substrate-binding pocket composed of hydrophobic amino acid residues ensures substrate docking for the stereospecific reaction of RrQR in spite of its loose interaction with the substrate. PMID:24507746

  1. Structural basis of stereospecific reduction by quinuclidinone reductase.

    PubMed

    Takeshita, Daijiro; Kataoka, Michihiko; Miyakawa, Takuya; Miyazono, Ken-Ichi; Kumashiro, Shoko; Nagai, Takahiro; Urano, Nobuyuki; Uzura, Atsuko; Nagata, Koji; Shimizu, Sakayu; Tanokura, Masaru

    2014-01-01

    Chiral molecule (R)-3-quinuclidinol, a valuable compound for the production of various pharmaceuticals, is efficiently synthesized from 3-quinuclidinone by using NADPH-dependent 3-quinuclidinone reductase (RrQR) from Rhodotorula rubra. Here, we report the crystal structure of RrQR and the structure-based mutational analysis. The enzyme forms a tetramer, in which the core of each protomer exhibits the ?/? Rossmann fold and contains one molecule of NADPH, whereas the characteristic substructures of a small lobe and a variable loop are localized around the substrate-binding site. Modeling and mutation analyses of the catalytic site indicated that the hydrophobicity of two residues, I167 and F212, determines the substrate-binding orientation as well as the substrate-binding affinity. Our results revealed that the characteristic substrate-binding pocket composed of hydrophobic amino acid residues ensures substrate docking for the stereospecific reaction of RrQR in spite of its loose interaction with the substrate. PMID:24507746

  2. Optical observation of correlated motions in dihydrofolate reductase

    NASA Astrophysics Data System (ADS)

    Xu, Mengyang; Niessen, Katherine; Pace, James; Cody, Vivian; Markelz, Andrea

    2015-03-01

    Enzyme function relies on its structural flexibility to make conformational changes for substrate binding and product release. An example of a metabolic enzyme where such structural changes are vital is dihydrofolate reductase (DHFR). DHFR is essential in both prokaryotes and eukaryotes for the nucleotide biosynthesis by catalyzing the reduction of dihydrofolate to tetrahydrofolate. NMR dynamical measurements found large amplitude fast dynamics that could indicate rigid-body, twisting-hinge motion for ecDHFR that may mediate flux. The role of such long-range correlated motions in function was suggested by the observed sharp decrease in enzyme activity for the single point mutation G121V, which is remote from active sites. This decrease in activity may be caused by the mutation interfering with the long-range intramolecular vibrations necessary for rapid access to functional configurations. We use our new technique of crystal anisotropy terahertz microscopy (CATM), to observe correlated motions in ecDHFR crystals with the bonding of NADPH and methotrexate. We compare the measured intramolecular vibrational spectrum with calculations using normal mode analysis.

  3. Temperature-sensitive DNA mutant of Chinese hamster ovary cells with a thermolabile ribonucleotide reductase activity.

    PubMed Central

    Wojcik, B E; Dermody, J J; Ozer, H L; Mun, B; Mathews, C K

    1990-01-01

    JB3-B is a Chinese hamster ovary cell mutant previously shown to be temperature sensitive for DNA replication (J. J. Dermody, B. E. Wojcik, H. Du, and H. L. Ozer, Mol. Cell. Biol. 6:4594-4601, 1986). It was chosen for detailed study because of its novel property of inhibiting both polyomavirus and adenovirus DNA synthesis in a temperature-dependent manner. Pulse-labeling studies demonstrated a defect in the rate of adenovirus DNA synthesis. Measurement of deoxyribonucleoside triphosphate (dNTP) pools as a function of time after shift of uninfected cultures from 33 to 39 degrees C revealed that all four dNTP pools declined at similar rates in extracts prepared either from whole cells or from rapidly isolated nuclei. Ribonucleoside triphosphate pools were unaffected by a temperature shift, ruling out the possibility that the mutation affects nucleoside diphosphokinase. However, ribonucleotide reductase activity, as measured in extracts, declined after cell cultures underwent a temperature shift, in parallel with the decline in dNTP pool sizes. Moreover, the activity of cell extracts was thermolabile in vitro, consistent with the model that the JB3-B mutation affects the structural gene for one of the ribonucleotide reductase subunits. The kinetics of dNTP pool size changes after temperature shift are quite distinct from those reported after inhibition of ribonucleotide reductase with hydroxyurea. An indirect effect on ribonucleotide reductase activity in JB3-B has not been excluded since human sequences other than those encoding the enzyme subunits can correct the temperature-sensitive growth defect in the mutant. Images PMID:2233712

  4. Curcumin analogs as potent aldose reductase inhibitors.

    PubMed

    Du, Zhi-Yun; Bao, Ya-Dan; Liu, Zhong; Qiao, Wei; Ma, Lin; Huang, Zhi-Shu; Gu, Lian-Quan; Chan, Albert S C

    2006-03-01

    In the present study, curcuminoids isolated from curcuma longa were demonstrated to possess inhibitory activities on bovine lens aldose reductase. In order to find more potent aldose reductase inhibitor, curcumin analogs were synthesized and evaluated for their ability to inhibit bovine lens aldose reductase enzyme. The results indicated that the compounds with tetrahydroxyl groups, 2,6-bis(3,4-dihydroxybenzylidene)cyclohexanone (A(2)), 2,5-bis(3,4-dihydroxybenzylidene)cyclopentanone (B(2)), 1,5-bis(3,4-dihydroxyphenyl)-1,4-pentadiene-3-one (C(2)), and 3,5-bis(3,4-dihydroxybenzylidene)-4-piperidone (D(2)) showed remarkably potent inhibitory effects on aldose reductase with IC(50) of 2.9 microM, 2.6 microM, 3.4 microM, and 4.9 microM, respectively. The structure-activity relationship revealed that the curcumin analogs with ortho-dihydroxyl groups could form a more tight affinity with aldose reductase to exert more potential inhibitory activities. PMID:16528793

  5. IN VITRO INHIBITION OF GLUTATHIONE REDUCTASE BY ARSENOTRI-GLUTATHIONE

    EPA Science Inventory

    Arsenotriglutathione, a product of the reduction of arsenate and the complexation of arsenite by glutathione, is a mixed type inhibitor of the reduction of glutathione disulfide by purified yeast glutathione reductase or the glutathione reductase activity in rabbit erythrocyte ly...

  6. Risk of venous thromboembolism associated with single and combined effects of Factor V Leiden, Prothrombin 20210A and Methylenetethraydrofolate reductase C677T: a meta-analysis involving over 11,000 cases and 21,000 controls

    PubMed Central

    Simone, B; De Stefano, V; Leoncini, E; Zacho, J; Martinelli, I; Emmerich, J; Rossi, E; Folsom, AR; Almawi, WY; Scarabin, PY; den Heijer, M; Cushman, M; Penco, S; Vaya, A; Angchaisuksiri, P; Okumus, G; Gemmati, D; Cima, S; Akar, N; Oguzulgen, KI; Ducros, V; Lichy, C; Fernandez-Miranda, C; Szczeklik, A; Nieto, JA; Torres, JD; Le Cam-Duchez, V; Ivanov, P; Cantu, C; Shmeleva, VM; Stegnar, M; Ogunyemi, D; Eid, SS; Nicolotti, N; De Feo, E; Ricciardi, W; Boccia, S

    2014-01-01

    BACKGROUND Genetic and environmental factors interact in determining the risk of venous thromboembolism (VTE). The risk associated with the polymorphic variants G1691A of factor V (Factor V Leiden,FVL), G20210A of prothrombin (PT20210A) and C677T of methylentetrahydrofolate reductase (C677T MTHFR) genes has been investigated in many studies. METHODS We performed a pooled analysis of case-control and cohort studies investigating in adults the association between each variant and VTE, published on Pubmed, Embase or Google through January 2010. Authors of eligible papers, were invited to provide all available individual data for the pooling. The Odds Ratio (OR) for first VTE associated with each variant, individually and combined with the others, were calculated with a random effect model, in heterozygotes and homozygotes (dominant model for FVL and PT20210A; recessive for C677T MTHFR). RESULTS We analysed 31 databases, including 11,239 cases and 21,521 controls. No significant association with VTE was found for homozygous C677T MTHFR (OR: 1.38; 95% confidence intervals [CI]: 0.98–1.93), whereas the risk was increased in carriers of either heterozygous FVL or PT20210 (OR=4.22; 95% CI: 3.35–5.32; and OR=2.79;95% CI: 2.25–3.46, respectively), in double hterozygotes (OR=3.42; 95%CI 1.64-7.13), and in homozygous FVL or PT20210A (OR=11.45; 95%CI: 6.79-19.29; and OR: 2.79; 95%CI: 2.25 – 3.46, respectively). The stratified analyses showed a stronger effect of FVL on individuals ?45 years (p-value for interaction = 0.036) and of PT20210A in women using oral contraceptives (p-value for interaction = 0.045). CONCLUSIONS In this large pooled analysis, inclusive of large studies like MEGA, no effect was found for C677T MTHFR on VTE; FVL and PT20210A were confirmed to be moderate risk factors. Notably, double carriers of the two genetic variants produced an impact on VTE risk significantly increased but weaker than previously thought. PMID:23900608

  7. Evaluation of nitrate reductase activity in Rhizobium japonicum

    SciTech Connect

    Streeter, J.G.; DeVine, P.J.

    1983-08-01

    Nitrate reductase activity was evaluated by four approaches, using four strains of Rhizobium japonicum and 11 chlorate-resistant mutants of the four strains. It was concluded that in vitro assays with bacteria or bacteroids provide the most simple and reliable assessment of the presence or absence of nitrate reductase. Nitrite reductase activity with methyl viologen and dithionite was found, but the enzyme activity does not confound the assay of nitrate reductase. 18 references

  8. Phylogenomics of Mycobacterium Nitrate Reductase Operon.

    PubMed

    Huang, Qinqin; Abdalla, Abualgasim Elgaili; Xie, Jianping

    2015-07-01

    NarGHJI operon encodes a nitrate reductase that can reduce nitrate to nitrite. This process enhances bacterial survival by nitrate respiration under anaerobic conditions. NarGHJI operon exists in many bacteria, especially saprophytic bacteria living in soil which play a key role in the nitrogen cycle. Most actinomycetes, including Mycobacterium tuberculosis, possess NarGHJI operons. M. tuberculosis is a facultative intracellular pathogen that expands in macrophages and has the ability to persist in a non-replicative form in granuloma lifelong. Nitrogen and nitrogen compounds play crucial roles in the struggle between M. tuberculosis and host. M. tuberculosis can use nitrate as a final electron acceptor under anaerobic conditions to enhance its survival. In this article, we reviewed the mechanisms regulating nitrate reductase expression and affecting its activity. Potential genes involved in regulating the nitrate reductase expression in M. tuberculosis were identified. The conserved NarG might be an alternative mycobacterium taxonomic marker. PMID:25980349

  9. Respiratory arsenate reductase as a bidirectional enzyme

    SciTech Connect

    Richey, Christine [Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States)] [Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States); Chovanec, Peter [Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States) [Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States); Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); Hoeft, Shelley E.; Oremland, Ronald S. [U.S. Geological Survey, 345 Middlefield Rd., MS 480, Menlo Park, CA 94025 (United States)] [U.S. Geological Survey, 345 Middlefield Rd., MS 480, Menlo Park, CA 94025 (United States); Basu, Partha [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States)] [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); Stolz, John F., E-mail: stolz@duq.edu [Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States)

    2009-05-01

    The haloalkaliphilic bacterium Alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (As(III)) to the reduction of nitrate and carbon dioxide. Analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (Aox), but instead possesses two operons that each encode a putative respiratory arsenate reductase (Arr). Here we show that one homolog is expressed under chemolithoautotrophic conditions and exhibits both arsenite oxidase and arsenate reductase activity. We also demonstrate that Arr from two arsenate respiring bacteria, Alkaliphilus oremlandii and Shewanella sp. strain ANA-3, is also biochemically reversible. Thus Arr can function as a reductase or oxidase. Its physiological role in a specific organism, however, may depend on the electron potentials of the molybdenum center and [Fe-S] clusters, additional subunits, or constitution of the electron transfer chain. This versatility further underscores the ubiquity and antiquity of microbial arsenic metabolism.

  10. Respiratory arsenate reductase as a bidirectional enzyme

    USGS Publications Warehouse

    Richey, C.; Chovanec, P.; Hoeft, S.E.; Oremland, R.S.; Basu, P.; Stolz, J.F.

    2009-01-01

    The haloalkaliphilic bacterium Alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (As(III)) to the reduction of nitrate and carbon dioxide. Analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (Aox), but instead possesses two operons that each encode a putative respiratory arsenate reductase (Arr). Here we show that one homolog is expressed under chemolithoautotrophic conditions and exhibits both arsenite oxidase and arsenate reductase activity. We also demonstrate that Arr from two arsenate respiring bacteria, Alkaliphilus oremlandii and Shewanella sp. strain ANA-3, is also biochemically reversible. Thus Arr can function as a reductase or oxidase. Its physiological role in a specific organism, however, may depend on the electron potentials of the molybdenum center and [Fe–S] clusters, additional subunits, or constitution of the electron transfer chain. This versatility further underscores the ubiquity and antiquity of microbial arsenic metabolism.

  11. Reaction Mechanism and Regulation of Mammalian Thioredoxin\\/Glutathione Reductase

    Microsoft Academic Search

    Qi-An Sun; Dan Su; Sergey V. Novoselov; Bradley A. Carlson; Dolph L. Hatfield; Vadim N. Gladyshev

    2005-01-01

    Thioredoxin\\/glutathione reductase (TGR) is a recently discovered member of the selenoprotein thioredoxin reductase family in mammals. In contrast to two other mammalian thioredoxin reductases, it contains an N-terminal glutaredoxin domain and exhibits a wide spectrum of enzyme activities. To elucidate the reaction mechanism and regulation of TGR, we prepared a recombinant mouse TGR in the selenoprotein form as well as

  12. The tyrosyl free radical in ribonucleotide reductase.

    PubMed Central

    Gräslund, A; Sahlin, M; Sjöberg, B M

    1985-01-01

    The enzyme, ribonucleotide reductase, catalyses the formation of deoxyribonucleotides from ribonucleotides, a reaction essential for DNA synthesis in all living cells. The Escherichia coli ribonucleotide reductase, which is the prototype of all known eukaryotic and virus-coded enzymes, consists of two nonidentical subunits, proteins B1 and B2. The B2 subunit contains an antiferromagnetically coupled pair of ferric ions and a stable tyrosyl free radical. EPR studies show that the tyrosyl radical, formed by loss of ferric ions and a stable tyrosyl free radical. EPR studies show that the tyrosyl radical, formed by loss of an electron, has its unpaired spin density delocalized in the aromatic ring of tyrosine. Effects of iron-radical interaction indicate a relatively close proximity between the iron center and the radical. The EPR signal of the radical can be studied directly in frozen packed cells of E. coli or mammalian origin, if the cells are made to overproduce ribonucleotide reductase. The hypothetic role of the tyrosyl free radical in the enzymatic reaction is not yet elucidated, except in the reaction with the inhibiting substrate analogue 2'-azido-CDP. In this case, the normal tyrosyl radical is destroyed with concomitant appearance of a 2'-azido-CDP-localized radical intermediate. Attempts at spin trapping of radical reaction intermediates have turned out negative. In E. coli the activity of ribonucleotide reductase may be regulated by enzymatic activities that interconvert a nonradical containing form and the fully active protein B2. In synchronized mammalian cells, however, the cell cycle variation of ribonucleotide reductase, studied by EPR, was shown to be due to de novo protein synthesis. Inhibitors of ribonucleotide reductase are of medical interest because of their ability to control DNA synthesis. One example is hydroxyurea, used in cancer therapy, which selectively destroys the tyrosyl free radical. PMID:3007085

  13. Semisynthesis and Characterization of Mammalian Thioredoxin Reductase

    PubMed Central

    Eckenroth, Brian; Harris, Katharine; Turanov, Anton A.; Gladyshev, Vadim N.; Raines, Ronald T.; Hondal, Robert J.

    2008-01-01

    Thioredoxin reductase and thioredoxin constitute the cellular thioredoxin system, which provides reducing equivalents to numerous intracellular target disulfides. Mammalian thioredoxin reductase contains the rare amino acid selenocysteine. Known as the “21st” amino acid, selenocysteine is inserted into proteins by recoding UGA stop codons. Some model eukaryotic organisms lack the ability to insert selenocysteine, and prokaryotes have a different recoding apparatus than do eukaryotes, thus making heterologous expression of mammalian selenoproteins difficult. Here, we present a semisynthetic method for preparing mammalian thioredoxin reductase. This method produces the first 487 amino acids of mouse thioredoxin reductase-3 as an intein fusion protein in Escherichia coli cells. The missing C-terminal tripeptide containing selenocysteine is then ligated to the thioester-tagged protein by expressed protein ligation. The semisynthetic version of thioredoxin reductase that we produce in this manner has kcat values ranging from 1500 min?1 to 2220 min?1 towards thioredoxin and has strong peroxidase activity, indicating a functional form of the enzyme. We produced the semisynthetic thioredoxin reductase with a total yield of 24 mg from 6 liters of E. coli culture (4 mg/L). This method allows production of a fully functional, semisynthetic selenoenzyme that is amenable to structure-function studies. A second semisynthetic system is also reported that makes use of peptide complementation to produce a partially active enzyme. The results of our peptide complementation studies reveal that a tetrapeptide that cannot ligate to the enzyme (Ac-Gly-Cys-Sec-Gly) can form a non-covalent complex with the truncated enzyme to form a weak complex. This non-covalent peptide/enzyme complex has 350–500 fold lower activity than the semisynthetic enzyme produced by peptide ligation. PMID:16618105

  14. Functional dissection and site-directed mutagenesis of the structural gene for NAD(P)H-nitrite reductase in Neurospora crassa.

    PubMed

    Colandene, J D; Garrett, R H

    1996-09-27

    Neurospora crassa NAD(P)H-nitrite reductase, encoded by the nit-6 gene, is a soluble, alpha2-type homodimeric protein composed of 127-kDa polypeptide subunits. This multicenter oxidation-reduction enzyme utilizes either NADH or NADPH as electron donor and possesses as prosthetic groups two iron-sulfur (Fe4S4) clusters, two siroheme groups, and two FAD molecules. The native activity of the enzyme is the NAD(P)H-dependent reduction of nitrite to ammonia. In addition, N. crassa nitrite reductase displays several partial activities in vitro, including a siroheme-independent NAD(P)H-cytochrome c reductase activity and an FAD-independent dithionite-nitrite reductase activity. These partial activities are presumed to be manifestations of discrete functional domains within the protein. A full-length nit-6 cDNA was constructed and used in developing an expression system within E. coli capable of yielding high levels of NADPH-nitrite reductase activity. Maximal expression was obtained in nirB- E. coli cells grown anaerobically at 22 +/- 1 degrees C, in conjunction with co-expression of a plasmid-borne cysG gene (encoding the rate-limiting enzyme in siroheme synthesis) and co-transformation with plasmid pGroESL (encoding bacterial chaperonins GroES and GroEL). Dissection of gene segments encoding putative functional domains within the nit-6 gene was performed. Expression of a partial cDNA construct encoding the FAD-/NAD-binding domain yielded extracts with NADPH-cytochrome c reductase activity but no NADPH-nitrite reductase activity or dithionite-nitrite reductase activity. Expression of a cDNA construct encoding the (Fe4S4)-siroheme-binding domain resulted in extracts possessing dithionite-nitrite reductase activity but no NADPH-nitrite reductase or NADPH-cytochrome c reductase activity. Analysis of site-directed mutations altering amino acid residues Cys-331 within the FAD-/NAD-binding domain and Ser-755 within the (Fe4S4)-siroheme-binding domain of the nitrite reductase demonstrated that these residues were not essential for native or partial enzyme activity. Cys-757 within the (Fe4S4)-siroheme-binding domain was essential for native enzyme activity. PMID:8798648

  15. Effect of the rib83Mutation on Riboflavin Synthesis and Iron Acquisition in the Yeast Pichia guilliermondii

    Microsoft Academic Search

    N. N. Stenchuk; V. I. Kutsiaba; B. V. Kshanovskaya; D. V. Fedorovich

    2001-01-01

    –Monogenicrib83mutation blocked riboflavin oversynthesis in the yeast Pichia guilliermondiiand lowered iron acquisition by cells, their ferric reductase activity, and the growth rate in iron-deficient media. Mutants with the combined mutations of rib83with rib80and rib81(the last two mutations impair the negative control of riboflavin synthesis and thus cause its oversynthesis) were unable to depress the enzymes of flavinogenesis (GTP cyclohydrolase and

  16. Structural prototypes for an extended family of flavoprotein reductases: comparison of phthalate dioxygenase reductase with ferredoxin reductase and ferredoxin.

    PubMed Central

    Correll, C. C.; Ludwig, M. L.; Bruns, C. M.; Karplus, P. A.

    1993-01-01

    The structure of phthalate dioxygenase reductase (PDR), a monomeric iron-sulfur flavoprotein that delivers electrons from NADH to phthalate dioxygenase, is compared to ferredoxin-NADP+ reductase (FNR) and ferredoxin, the proteins that reduce NADP+ in the final reaction of photosystem I. The folding patterns of the domains that bind flavin, NAD(P), and [2Fe-2S] are very similar in the two systems. Alignment of the X-ray structures of PDR and FNR substantiates the assignment of features that characterize a family of flavoprotein reductases whose members include cytochrome P-450 reductase, sulfite and nitrate reductases, and nitric oxide synthase. Hallmarks of this subfamily of flavoproteins, here termed the FNR family, are an antiparallel beta-barrel that binds the flavin prosthetic group, and a characteristic variant of the classic pyridine nucleotide-binding fold. Despite the similarities between FNR and PDR, attempts to model the structure of a dissociable FNR:ferredoxin complex by analogy with PDR reveal features that are at odds with chemical crosslinking studies (Zanetti, G., Morelli, D., Ronchi, S., Negri, A., Aliverti, A., & Curti, B., 1988, Biochemistry 27, 3753-3759). Differences in the binding sites for flavin and pyridine nucleotides determine the nucleotide specificities of FNR and PDR. The specificity of FNR for NADP+ arises primarily from substitutions in FNR that favor interactions with the 2' phosphate of NADP+. Variations in the conformation and sequences of the loop adjoining the flavin phosphate affect the selectivity for FAD versus FMN. The midpoint potentials for reduction of the flavin and [2Fe-2S] groups in PDR are higher than their counterparts in FNR and spinach ferredoxin, by about 120 mV and 260 mV, respectively. Comparisons of the structure of PDR with spinach FNR and with ferredoxin from Anabaena 7120, along with calculations of electrostatic potentials, suggest that local interactions, including hydrogen bonds, are the dominant contributors to these differences in potential. PMID:8298460

  17. Nitrate reductase and nitrite reductase activity in free-living cells and bacteroids of Rhizobium loti

    Microsoft Academic Search

    J. Monza; M. J. Delgado; E. J. Bedmar

    1992-01-01

    Cells of Rhizobium loti strains T1 and U226 cultured in defined medium with glutamate as the only nitrogen source and bacteroids isolated from root nodules of Lotus corniculatus, L. pedunculatus and L. tenuis did not show constitutive (non-nitrate induced) nitrate reductase activity (NRA). In contrast, nitrite reductase activity (NiRA) was present in both free-living cells and bacteroids of either strain

  18. Functional studies of aldo-keto reductases in Saccharomyces cerevisiae*

    PubMed Central

    Chang, Qing; Griest, Terry A.; Harter, Theresa M.; Petrash, J. Mark

    2007-01-01

    SUMMARY We utilized the budding yeast Saccharomyces cerevisiae as a model to systematically explore physiological roles for yeast and mammalian aldo-keto reductases. Six open reading frames encoding putative aldo-keto reductases were identified when the yeast genome was queried against the sequence for human aldose reductase, the prototypical mammalian aldo-keto reductase. Recombinant proteins produced from five of these yeast open reading frames demonstrated NADPH-dependent reductase activity with a variety of aldehyde and ketone substrates. A triple aldo-keto reductase null mutant strain demonstrated a glucose-dependent heat shock phenotype which could be rescued by ectopic expression of human aldose reductase. Catalytically-inactive mutants of human or yeast aldo-keto reductases failed to effect a rescue of the heat shock phenotype, suggesting that the phenotype results from either an accumulation of one or more unmetabolized aldo-keto reductase substrates or a synthetic deficiency of aldo-keto reductase products generated in response to heat shock stress. These results suggest that multiple aldo-keto reductases fulfill functionally redundant roles in the stress response in yeast. PMID:17140678

  19. Functional studies of aldo-keto reductases in Saccharomyces cerevisiae.

    PubMed

    Chang, Qing; Griest, Terry A; Harter, Theresa M; Petrash, J Mark

    2007-03-01

    We utilized the budding yeast Saccharomyces cerevisiae as a model to systematically explore physiological roles for yeast and mammalian aldo-keto reductases. Six open reading frames encoding putative aldo-keto reductases were identified when the yeast genome was queried against the sequence for human aldose reductase, the prototypical mammalian aldo-keto reductase. Recombinant proteins produced from five of these yeast open reading frames demonstrated NADPH-dependent reductase activity with a variety of aldehyde and ketone substrates. A triple aldo-keto reductase null mutant strain demonstrated a glucose-dependent heat shock phenotype which could be rescued by ectopic expression of human aldose reductase. Catalytically-inactive mutants of human or yeast aldo-keto reductases failed to effect a rescue of the heat shock phenotype, suggesting that the phenotype results from either an accumulation of one or more unmetabolized aldo-keto reductase substrates or a synthetic deficiency of aldo-keto reductase products generated in response to heat shock stress. These results suggest that multiple aldo-keto reductases fulfill functionally redundant roles in the stress response in yeast. PMID:17140678

  20. Control of dihydrofolate reductase messenger ribonucleic acid production

    SciTech Connect

    Leys, E.J.; Kellems, R.E.

    1981-11-01

    The authors used methotrexate-resistant mouse cells in which dihydrofolate reductase levels are approximately 500 times normal to study the effect of growth stimulation on dihydrofolate reductase gene expression. As a result of growth stimulation, the relative rate of dihydrofolate reductase protein synthesis increased threefold, reaching a maximum between 25 and 30 h after stimulation. The relative rate of dihydrofolate reductase messenger ribonucleic acid production (i.e., the appearance of dihydrofolate reductase messenger ribonucleic acid in the cytoplasm) increased threefold after growth stimulation and was accompanied by a corresponding increase in the relative steady-state level of dihydrofolate reductase ribonucleic acid in the nucleus. However, the increase in the nuclear level of dihydrofolate reductase ribonucleic acid was not accompanied by a significant increase in the relative rate of transcription of the dihydrofolate reductase genes. These data indicated that the relative rate of appearance of dihydrofolate reductase messenger ribonucleic acid in the cytoplasm depends on the relative stability of the dihydrofolate reductase ribonucleic acid sequences in the nucleus and is not dependent on the relative rate of transcription of the dihydrofolate reductase genes.

  1. Methemoglobin reductase in three species of Bovidae

    Microsoft Academic Search

    Ronald D. Fulton; J. Caldwell; D. F. Weseli

    1978-01-01

    Isoelectric focusing of red cell hemolysates revealed several isozymes that stain for NADH-methemoglobin reductase. Evidence for two different genetic loci controlling the banding patterns was obtained. One locus controlled a single band present in all animals tested. The second locus controlled ten different banding patterns that could be accounted for by four codominant alleles. Band B occurred in Bison bison.

  2. Nitrate reductase in Peru current phytoplankton

    Microsoft Academic Search

    R. W. Eppley; T. T. Packard; J. J. MacIsaac

    1970-01-01

    Nitrate reductase (NR) activity was assayed by measuring the NADH-dependent formation of nitrite in phytoplankton extracts. NR specific activity increased with the nitrate concentration of the water in upwelling areas of the Peru Current. The temperature optimum for NR for natural phytoplankton was 15° to 20°C. NR activity showed diel periodicity, with maximum activity about noon and minimum activity near

  3. Phytochemicals in Broccoli Transcriptionally Induce Thioredoxin Reductase

    Microsoft Academic Search

    Korry J. Hintze; Karl Wald; John W. Finley

    2005-01-01

    Previous studies have demonstrated transcriptional induction of thioredoxin reductase (TR) by sulforaphane (SF) purified from broccoli; the mechanism of induction is via an antioxidant response element (ARE) in the promoter region of the gene. The purpose of the present study was to further characterize the induction of TR by compounds in broccoli and to determine if SF is the primary

  4. Post-translational Regulation of Nitrate Reductase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrate reductase (NR) catalyzes the reduction of nitrate to nitrite, which is the first step in the nitrate assimilation pathway, but can also reduce nitrite to nitric oxide (NO), an important signaling molecule that is thought to mediate a wide array of of developmental and physiological processes...

  5. Plasma homocysteine, MTHFR C677T, CBS 844ins68bp, and MTHFD1 G1958A polymorphisms in spontaneous cervical artery dissections

    Microsoft Academic Search

    Carsten Konrad; Georg A. Müller; Claus Langer; Gregor Kuhlenbäumer; Klaus Berger; Darius G. Nabavi; Rainer Dziewas; Florian Stögbauer; Erich B. Ringelstein; Ralf Junker

    2004-01-01

    Mild hyperhomocysteinemia is a probable risk factor for atherosclerotic diseases and stroke. Recently, associations of elevated plasma homocysteine concentrations in the acute phase and of MTHFR 677 TT genotype with spontaneous cervical artery dissections (sCAD) have been reported. The purpose of this study was to test this hypothesis in the currently largest sample of patients with sCAD, taking into account

  6. Association between MTHFR C677T and A1298C, and MTRR A66G polymorphisms and susceptibility to schizophrenia in a Syrian study cohort.

    PubMed

    Lajin, Bassam; Alhaj Sakur, Amir; Michati, Roula; Alachkar, Amal

    2012-06-01

    The folate-homocystiene metabolic pathway has been shown to be involved in the susceptibility for developing schizophrenia by several studies. In the present study we investigated the role of three common polymorphisms of the folate-homocysteine metabolic pathway in an Arab population from Syria consisting of 85 schizophrenic patients and 126 healthy controls. The studied polymorphisms included the MTHFR C677T and A1298C, and MTRR A66G, all of which result into amino acid changes, and were previously shown to yield decreased enzymatic activity and alter plasma homocysteine concentration. While MTHFR C677T and A1298C polymorphisms were not previously studied in an Arab population with respect to the susceptibility for developing schizophrenia, the MTRR A66G was not previously investigated in any population around the world. Our results indicated a strong association between MTHFR A1298C and schizophrenia. The variant C allele frequency was significantly higher in the patients group (40% vs 29.4%, OR=1.6, 95% CI (1.06-2.41), p=0.023). A statistically significant association was found for MTHFR 677TT genotype under the recessive model in the male patients subgroup (OR=2.6, 95% CI (1.04-6.5), p=0.036), and MTHFR 677CT genotype under the overdominant model in the total patients group (OR=0.52 95% CI (0.29-0.92), p=0.024). No statistically significant association was found for MTRR A66G polymorphism on an individual basis. However, a borderline association was found for the CC/GG (C677T/A66G) compound genotype (OR=2.24, 95% CI (0.97-5.15), p=0.053). Our results support the hypothesis of association between schizophrenia and folate-homocystiene metabolic pathway genes. PMID:22813657

  7. Structural basis for high substrate-binding affinity and enantioselectivity of 3-quinuclidinone reductase AtQR.

    PubMed

    Hou, Feng; Miyakawa, Takuya; Kataoka, Michihiko; Takeshita, Daijiro; Kumashiro, Shoko; Uzura, Atsuko; Urano, Nobuyuki; Nagata, Koji; Shimizu, Sakayu; Tanokura, Masaru

    2014-04-18

    (R)-3-Quinuclidinol, a useful compound for the synthesis of various pharmaceuticals, can be enantioselectively produced from 3-quinuclidinone by 3-quinuclidinone reductase. Recently, a novel NADH-dependent 3-quinuclidionone reductase (AtQR) was isolated from Agrobacterium tumefaciens, and showed much higher substrate-binding affinity (>100 fold) than the reported 3-quinuclidionone reductase (RrQR) from Rhodotorula rubra. Here, we report the crystal structure of AtQR at 1.72 Å. Three NADH-bound protomers and one NADH-free protomer form a tetrameric structure in an asymmetric unit of crystals. NADH not only acts as a proton donor, but also contributes to the stability of the ?7 helix. This helix is a unique and functionally significant part of AtQR and is related to form a deep catalytic cavity. AtQR has all three catalytic residues of the short-chain dehydrogenases/reductases family and the hydrophobic wall for the enantioselective reduction of 3-quinuclidinone as well as RrQR. An additional residue on the ?7 helix, Glu197, exists near the active site of AtQR. This acidic residue is considered to form a direct interaction with the amine part of 3-quinuclidinone, which contributes to substrate orientation and enhancement of substrate-binding affinity. Mutational analyses also support that Glu197 is an indispensable residue for the activity. PMID:24642255

  8. The co-chaperone and reductase ERdj5 facilitates rod opsin biogenesis and quality control.

    PubMed

    Athanasiou, Dimitra; Bevilacqua, Dalila; Aguila, Monica; McCulley, Caroline; Kanuga, Naheed; Iwawaki, Takao; Paul Chapple, J; Cheetham, Michael E

    2014-12-15

    Mutations in rhodopsin, the light-sensitive protein of rod cells, are the most common cause of autosomal dominant retinitis pigmentosa (ADRP). Many rod opsin mutations, such as P23H, lead to misfolding of rod opsin with detrimental effects on photoreceptor function and viability. Misfolded P23H rod opsin and other mutations in the intradiscal domain are characterized by the formation of an incorrect disulphide bond between C185 and C187, as opposed to the correct and highly conserved C110-C187 disulphide bond. Therefore, we tested the hypothesis that incorrect disulphide bond formation might be a factor that affects the biogenesis of rod opsin by studying wild-type (WT) or P23H rod opsin in combination with amino acid substitutions that prevent the formation of incorrect disulphide bonds involving C185. These mutants had altered traffic dynamics, suggesting a requirement for regulation of disulphide bond formation/reduction during rod opsin biogenesis. Here, we show that the BiP co-chaperone and reductase protein ERdj5 (DNAJC10) regulates this process. ERdj5 overexpression promoted the degradation, improved the endoplasmic reticulum mobility and prevented the aggregation of P23H rod opsin. ERdj5 reduction by shRNA delayed rod opsin degradation and promoted aggregation. The reductase and co-chaperone activity of ERdj5 were both required for these effects on P23H rod opsin. Furthermore, mutations in these functional domains acted as dominant negatives that affected WT rod opsin biogenesis. Collectively, these data identify ERdj5 as a member of the proteostasis network that regulates rod opsin biogenesis and supports a role for disulphide bond formation/reduction in rod opsin biogenesis and disease. PMID:25055872

  9. The co-chaperone and reductase ERdj5 facilitates rod opsin biogenesis and quality control

    PubMed Central

    Athanasiou, Dimitra; Bevilacqua, Dalila; Aguila, Monica; McCulley, Caroline; Kanuga, Naheed; Iwawaki, Takao; Paul Chapple, J.; Cheetham, Michael E.

    2014-01-01

    Mutations in rhodopsin, the light-sensitive protein of rod cells, are the most common cause of autosomal dominant retinitis pigmentosa (ADRP). Many rod opsin mutations, such as P23H, lead to misfolding of rod opsin with detrimental effects on photoreceptor function and viability. Misfolded P23H rod opsin and other mutations in the intradiscal domain are characterized by the formation of an incorrect disulphide bond between C185 and C187, as opposed to the correct and highly conserved C110–C187 disulphide bond. Therefore, we tested the hypothesis that incorrect disulphide bond formation might be a factor that affects the biogenesis of rod opsin by studying wild-type (WT) or P23H rod opsin in combination with amino acid substitutions that prevent the formation of incorrect disulphide bonds involving C185. These mutants had altered traffic dynamics, suggesting a requirement for regulation of disulphide bond formation/reduction during rod opsin biogenesis. Here, we show that the BiP co-chaperone and reductase protein ERdj5 (DNAJC10) regulates this process. ERdj5 overexpression promoted the degradation, improved the endoplasmic reticulum mobility and prevented the aggregation of P23H rod opsin. ERdj5 reduction by shRNA delayed rod opsin degradation and promoted aggregation. The reductase and co-chaperone activity of ERdj5 were both required for these effects on P23H rod opsin. Furthermore, mutations in these functional domains acted as dominant negatives that affected WT rod opsin biogenesis. Collectively, these data identify ERdj5 as a member of the proteostasis network that regulates rod opsin biogenesis and supports a role for disulphide bond formation/reduction in rod opsin biogenesis and disease. PMID:25055872

  10. A Peroxisomal Disorder of Severe Intellectual Disability, Epilepsy, and Cataracts Due to Fatty Acyl-CoA Reductase 1 Deficiency

    PubMed Central

    Buchert, Rebecca; Tawamie, Hasan; Smith, Christopher; Uebe, Steffen; Innes, A. Micheil; Al Hallak, Bassam; Ekici, Arif B.; Sticht, Heinrich; Schwarze, Bernd; Lamont, Ryan E.; Parboosingh, Jillian S.; Bernier, Francois P.; Abou Jamra, Rami

    2014-01-01

    Rhizomelic chondrodysplasia punctata (RCDP) is a group of disorders with overlapping clinical features including rhizomelia, chondrodysplasia punctata, coronal clefts, cervical dysplasia, congenital cataracts, profound postnatal growth retardation, severe intellectual disability, and seizures. Mutations in PEX7, GNPAT, and AGPS, all involved in the plasmalogen-biosynthesis pathway, have been described in individuals with RCDP. Here, we report the identification of mutations in another gene in plasmalogen biosynthesis, fatty acyl-CoA reductase 1 (FAR1), in two families affected by severe intellectual disability, early-onset epilepsy, microcephaly, congenital cataracts, growth retardation, and spasticity. Exome analyses revealed a homozygous in-frame indel mutation (c.495_507delinsT [p.Glu165_Pro169delinsAsp]) in two siblings from a consanguineous family and compound-heterozygous mutations (c.[787C>T];[1094A>G], p.[Arg263?];[Asp365Gly]) in a third unrelated individual. FAR1 reduces fatty acids to their respective fatty alcohols for the plasmalogen-biosynthesis pathway. To assess the pathogenicity of the identified mutations, we transfected human embryonic kidney 293 cells with plasmids encoding FAR1 with either wild-type or mutated constructs and extracted the lipids from the cells. We screened the lipids with gas chromatography and mass spectrometry and found that all three mutations abolished the reductase activity of FAR1, given that no fatty alcohols could be detected. We also observed reduced plasmalogens in red blood cells in one individual to a range similar to that seen in individuals with RCDP, further supporting abolished FAR1 activity. We thus expand the spectrum of clinical features associated with defects in plasmalogen biosynthesis to include FAR1 deficiency as a cause of syndromic severe intellectual disability with cataracts, epilepsy, and growth retardation but without rhizomelia. PMID:25439727

  11. FRUCTOSE-6-PHOSPHATE REDUCTASE FROM SALMONELLA GALLINARUM.

    PubMed

    ZANCAN, G T; BACILA, M

    1964-03-01

    Zancan, Glaci T. (Universidade do Paraná, Curitiba, Paraná, Brazil), and Metry Bacila. Fructose-6-phosphate reductase from Salmonella gallinarum. J. Bacteriol. 87:614-618. 1964.-A fructose-6-phosphate reductase present in cell-free extracts of Salmonella gallinarum was purified approximately 42 times. The optimal pH for this enzyme is 8.0. The enzyme is specific for fructose-6-phosphate and reduced nicotinamide adenine dinucleotide (NADH). The dissociation constants are 1.78 x 10(-4)m for fructose-6-phosphate and 8.3 x 10(-5)m for NADH. The Q(10), reaction order, and equilibrium constant were determined. The enzyme is sensitive to p-chloromercuribenzoic acid, but not to o-iodosobenzoic acid nor to N-ethylmaleimide. PMID:14127579

  12. Polymorphisms and haplotypes in methylenetetrahydrofolate reductase gene and head and neck squamous cell carcinoma risk

    Microsoft Academic Search

    Ana Lívia Silva Galbiatti; Mariangela Torreglosa Ruiz; Juliana Olsen Rodrigues; Luiz Sérgio Raposo; José Victor Maníglia; Érika Cristina Pavarino; Eny Maria Goloni-Bertollo

    Functional polymorphisms in genes encoding enzymes involved in folate metabolism might modulate head and neck carcinoma risk\\u000a because folate participates in DNA methylation and synthesis. We therefore conducted a case–control study of 853 individuals\\u000a (322 head and neck cancer cases and 531 non-cancer controls) to investigate associations among MTHFR C677T and MTHFR A1298C polymorphisms and head and neck squamous cell

  13. Methemoglobin reductase in three species of bovidae

    E-print Network

    Fulton, Ronald Dale

    1976-01-01

    reductase variability as related to NAD glycohydrolase activity. Arch. Biochem. Biophys. 164:386. Bloom, G. E. and H. S. Zarkowsky. 1969. Heterogeneity of the enzymatic defect in congenital methemoglobinaemia. New Eng. J. Med. 281:919. Brewer, G, J. , J...:1555. Jaffe, E. R. 1963. The reduction of methemoglobin in erythrocytes of a patient with congenital methemoglobinemia, subJects with erythrocytes glucose-6-phosphate dehydrogenase deficiency, snd normal individuals. Blood. 21:561, Jaffe, E. R. 1969. DPNH...

  14. Nitrate reductase activity in Zostera marina

    Microsoft Academic Search

    N. C. Roth; A. M. Pregnall

    1988-01-01

    Eelgrass (Zostera marina L.) has access to nutrient pools in both the water column and sediments. We investigated the potential for eelgrass to utilize nitrate nitrogen by measuring nitrate reductase (NR) activity with an in vivo tissue assay. Optimal incubation media contained 60 mM nitrate, 100 mM phosphate, and 0.5% 1-propanol at pH 7.0. Leaves had significantly higher NR activity

  15. Characterization of erythrose reductases from filamentous fungi

    PubMed Central

    2013-01-01

    Proteins with putative erythrose reductase activity have been identified in the filamentous fungi Trichoderma reesei, Aspergillus niger, and Fusarium graminearum by in silico analysis. The proteins found in T. reesei and A. niger had earlier been characterized as glycerol dehydrogenase and aldehyde reductase, respectively. Corresponding genes from all three fungi were cloned, heterologously expressed in Escherichia coli, and purified. Subsequently, they were used to establish optimal enzyme assay conditions. All three enzymes strictly require NADPH as cofactor, whereas with NADH no activity could be observed. The enzymatic characterization of the three enzymes using ten substrates revealed high substrate specificity and activity with D-erythrose and D-threose. The enzymes from T. reesei and A. niger herein showed comparable activities, whereas the one from F. graminearum reached only about a tenth of it for all tested substrates. In order to proof in vivo the proposed enzyme function, we overexpressed the erythrose reductase-encoding gene in T. reesei. An increased production of erythritol by the recombinant strain compared to the parental strain could be detected. PMID:23924507

  16. Aldo-Keto Reductases in the Eye

    PubMed Central

    Huang, Shun Ping; Palla, Suryanarayana; Ruzycki, Philip; Varma, Ross Arjun; Harter, Theresa; Reddy, G. Bhanuprakesh; Petrash, J. Mark

    2010-01-01

    Aldose reductase (AKR1B1) is an NADPH-dependent aldo-keto reductase best known as the rate-limiting enzyme of the polyol pathway. Accelerated glucose metabolism through this pathway has been implicated in diabetic cataract and retinopathy. Some human tissues contain AKR1B1 as well as AKR1B10, a closely related member of the aldo-keto reductase gene superfamily. This opens the possibility that AKR1B10 may also contribute to diabetic complications. The goal of the current study was to characterize the expression profiles of AKR1B1 and AKR1B10 in the human eye. Using quantitative reverse transcriptase-PCR and immunohistochemical staining, we observed expression of both AKR genes in cornea, iris, ciliary body, lens, and retina. Expression of AKR1B1 was the highest in lens and retina, whereas AKR1B10 was the highest in cornea. Lenses from transgenic mice designed for overexpression of AKR1B10 were not significantly different from nontransgenic controls, although a significant number developed a focal defect in the anterior lens epithelium following 6 months of experimentally induced diabetes. However, lenses from AKR1B10 mice remained largely transparent following longterm diabetes. These results indicate that AKR1B1 and AKR1B10 may have different functional properties in the lens and suggest that AKR1B10 does not contribute to the pathogenesis of diabetic cataract in humans. PMID:20628518

  17. Aldo-keto reductases in the eye.

    PubMed

    Huang, Shun Ping; Palla, Suryanarayana; Ruzycki, Philip; Varma, Ross Arjun; Harter, Theresa; Reddy, G Bhanuprakesh; Petrash, J Mark

    2010-01-01

    Aldose reductase (AKR1B1) is an NADPH-dependent aldo-keto reductase best known as the rate-limiting enzyme of the polyol pathway. Accelerated glucose metabolism through this pathway has been implicated in diabetic cataract and retinopathy. Some human tissues contain AKR1B1 as well as AKR1B10, a closely related member of the aldo-keto reductase gene superfamily. This opens the possibility that AKR1B10 may also contribute to diabetic complications. The goal of the current study was to characterize the expression profiles of AKR1B1 and AKR1B10 in the human eye. Using quantitative reverse transcriptase-PCR and immunohistochemical staining, we observed expression of both AKR genes in cornea, iris, ciliary body, lens, and retina. Expression of AKR1B1 was the highest in lens and retina, whereas AKR1B10 was the highest in cornea. Lenses from transgenic mice designed for overexpression of AKR1B10 were not significantly different from nontransgenic controls, although a significant number developed a focal defect in the anterior lens epithelium following 6 months of experimentally induced diabetes. However, lenses from AKR1B10 mice remained largely transparent following longterm diabetes. These results indicate that AKR1B1 and AKR1B10 may have different functional properties in the lens and suggest that AKR1B10 does not contribute to the pathogenesis of diabetic cataract in humans. PMID:20628518

  18. Ribonucleotide Reductase in Blue-Green Algae: Dependence on Adenosylcobalamin

    Microsoft Academic Search

    F. K. Gleason; J. M. Wood

    1976-01-01

    Ten species of freshwater blue-green algae exhibit an adenosylcobalamin-dependent ribonucleotide reductase, thus explaining the requirement for cobalt by these organisms. The evidence suggests a phylogenetic affinity between the cyanophytes and bacteria, such as Clostridium and Rhizobium, and the euglenoid flagellates, which also use the cofactor-dependent reductase. In contrast, the ribonucleotide reductase reaction in the few green algae surveyed shows no

  19. Evidence that the amino acid residue Cys117 of chloroplastic monodehydroascorbate reductase is involved in its activity and structural stability.

    PubMed

    Li, Feng; Wu, Qing-Yun; Sun, Yan-Li; Ma, Na-Na; Wang, Xiao-Yun; Meng, Qing-Wei

    2010-04-01

    Monodehydroascorbate reductase (MDAR; EC 1.6.5.4) is crucial for AsA regeneration and essential for maintaining the reduced pool of AsA. And the amino acid residue C117 of chloroplastic MDAR is the conserved cysteine residue in MDAR isoforms. A series mutation of conserved amino acid residue cysteine117 (C117) was constructed to investigate its role in MDAR structural stability and activity. Our study revealed that mutation in this conserved residue could cause pronounced loss of activity and conformational changes. Spectroscopic experiments indicated that these mutations influenced transition from the molten globule intermediate to the native state in folding process. These results suggested that amino acid residue C117 played a relatively important role in keeping MDAR structural stability and activity. PMID:20085781

  20. Nitrite Reductase NirS Is Required for Type III Secretion System Expression and Virulence in the Human Monocyte Cell Line THP-1 by Pseudomonas aeruginosa?

    PubMed Central

    Van Alst, Nadine E.; Wellington, Melanie; Clark, Virginia L.; Haidaris, Constantine G.; Iglewski, Barbara H.

    2009-01-01

    The nitrate dissimilation pathway is important for anaerobic growth in Pseudomonas aeruginosa. In addition, this pathway contributes to P. aeruginosa virulence by using the nematode Caenorhabditis elegans as a model host, as well as biofilm formation and motility. We used a set of nitrate dissimilation pathway mutants to evaluate the virulence of P. aeruginosa PA14 in a model of P. aeruginosa-phagocyte interaction by using the human monocytic cell line THP-1. Both membrane nitrate reductase and nitrite reductase enzyme complexes were important for cytotoxicity during the interaction of P. aeruginosa PA14 with THP-1 cells. Furthermore, deletion mutations in genes encoding membrane nitrate reductase (?narGH) and nitrite reductase (?nirS) produced defects in the expression of type III secretion system (T3SS) components, extracellular protease, and elastase. Interestingly, exotoxin A expression was unaffected in these mutants. Addition of exogenous nitric oxide (NO)-generating compounds to ?nirS mutant cultures restored the production of T3SS phospholipase ExoU, whereas nitrite addition had no effect. These data suggest that NO generated via nitrite reductase NirS contributes to the regulation of expression of selected virulence factors in P. aeruginosa PA14. PMID:19651860

  1. Isobutyraldehyde production from Escherichia coli by removing aldehyde reductase activity

    PubMed Central

    2012-01-01

    Background Increasing global demand and reliance on petroleum-derived chemicals will necessitate alternative sources for chemical feedstocks. Currently, 99% of chemical feedstocks are derived from petroleum and natural gas. Renewable methods for producing important chemical feedstocks largely remain unaddressed. Synthetic biology enables the renewable production of various chemicals from microorganisms by constructing unique metabolic pathways. Here, we engineer Escherichia coli for the production of isobutyraldehyde, which can be readily converted to various hydrocarbons currently derived from petroleum such as isobutyric acid, acetal, oxime and imine using existing chemical catalysis. Isobutyraldehyde can be readily stripped from cultures during production, which reduces toxic effects of isobutyraldehyde. Results We adopted the isobutanol pathway previously constructed in E. coli, neglecting the last step in the pathway where isobutyraldehyde is converted to isobutanol. However, this strain still overwhelmingly produced isobutanol (1.5?g/L/OD600 (isobutanol) vs 0.14?g/L/OD600 (isobutyraldehyde)). Next, we deleted yqhD which encodes a broad-substrate range aldehyde reductase known to be active toward isobutyraldehyde. This strain produced isobutanol and isobutyraldehyde at a near 1:1 ratio, indicating further native isobutyraldehyde reductase (IBR) activity in E. coli. To further eliminate isobutanol formation, we set out to identify and remove the remaining IBRs from the E. coli genome. We identified 7 annotated genes coding for IBRs that could be active toward isobutyraldehyde: adhP, eutG, yiaY, yjgB, betA, fucO, eutE. Individual deletions of the genes yielded only marginal improvements. Therefore, we sequentially deleted all seven of the genes and assessed production. The combined deletions greatly increased isobutyraldehyde production (1.5?g/L/OD600) and decreased isobutanol production (0.4?g/L/OD600). By assessing production by overexpression of each candidate IBR, we reveal that AdhP, EutG, YjgB, and FucO are active toward isobutyraldehyde. Finally, we assessed long-term isobutyraldehyde production of our best strain containing a total of 15 gene deletions using a gas stripping system with in situ product removal, resulting in a final titer of 35?g/L after 5?days. Conclusions In this work, we optimized E. coli for the production of the important chemical feedstock isobutyraldehyde by the removal of IBRs. Long-term production yielded industrially relevant titers of isobutyraldehyde with in situ product removal. The mutational load imparted on E. coli in this work demonstrates the versatility of metabolic engineering for strain improvements. PMID:22731523

  2. Stress, Mutators, Mutations and Stress Resistance

    Microsoft Academic Search

    Jonathan Gressel; Avraham A. Levy

    \\u000a Organisms need genetic mechanisms to rapidly adapt to changing, stressful environments. Having a high mutation frequency would\\u000a have a drag on a population due to the deleterious nature of mutations, but having a sub-population with high mutation rate\\u000a due to the presence of mutator genes seems to be nature’s solution. Far more is known about mutator genes in bacteria than

  3. Evidence for the co-existence of glutathione reductase and trypanothione reductase in the non-trypanosomatid Euglenozoa: Euglena gracilis Z

    Microsoft Academic Search

    Françoise Montrichard; Fabienne Le Guen; Danielle L Laval-Martin; Elisabeth Davioud-Charvet

    1999-01-01

    Two NADPH-dependent disulfide reductases, glutathione reductase and trypanothione reductase, were shown to be present in Euglena gracilis, purified to homogeneity and characterized. The glutathione reductase (Mr 50 kDa) displays a high specificity towards glutathione disulfide with a KM of 54 ?M. The amino acid sequences of two peptides derived from the trypanothione reductase (Mr 54 kDa) show a high level

  4. A Case of Diverticular Perforation in a Young Patient with Rheumatoid Arthritis on Methotrexate

    PubMed Central

    Chang, Ian; Guggenheim, Carla; Laird-Fick, Heather

    2015-01-01

    Background. Disease-modifying antirheumatic drugs (DMARDs), such as methotrexate (MTX), are associated with gastrointestinal toxicity. MTX inhibits dihydrofolate reductase, but it is unclear if polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene predict toxicity. Case. We describe a 33-year-old male with polyarticular rheumatoid arthritis who developed sigmoid diverticular perforation while receiving methotrexate, folic acid, prednisone, and naproxen. He tested heterozygous for the C677T allele MTHFR gene. Discussion. Rheumatoid arthritis and its treatments are associated with increased risk of gastrointestinal disease. In one study, perforation was highest among individuals with concomitant exposure to NSAIDs, nonbiologic DMARDs, and glucocorticoids. Multiple mutations of the MTHFR gene have been identified, but their association with MTX toxicity is unclear. This case adds to a growing body of literature that could help inform the treatment of others in the future.

  5. Role of active site tyrosine residues in catalysis by human glutathione reductase.

    PubMed

    Krauth-Siegel, R L; Arscott, L D; Schönleben-Janas, A; Schirmer, R H; Williams, C H

    1998-10-01

    Tyr114 and Tyr197 are highly conserved residues in the active site of human glutathione reductase, Tyr114 in the glutathione disulfide (GSSG) binding site and Tyr197 in the NADPH site. Mutation of either residue has profound effects on catalysis. Y197S and Y114L have 17% and 14% the activity of the wild-type enzyme, respectively. Mutation of Tyr197, in the NADPH site, leads to a decrease in Km for GSSG, and mutation of Tyr114, in the GSSG site, leads to a decrease in Km for NADPH. This behavior is predicted for enzymes operating by a ping-pong mechanism where both half-reactions partially limit turnover. Titration of the wild-type enzyme or Y114L with NADPH proceeds in two phases, Eox to EH2 and EH2 to EH2-NADPH. In contrast, Y197S reacts monophasically, showing that excess NADPH fails to enhance the absorbance of the thiolate-FAD charge-transfer complex, the predominant EH2 form of glutathione reductase. The reductive half-reactions of the wild-type enzyme and of Y114L are similar; FAD reduction is fast (approximately 500 s-1 at 4 degreesC) and thiolate-FAD charge-transfer complex formation has a rate of 100 s-1. In Y197S, these rates are only 78 and 5 s-1, respectively. The oxidative half-reaction, the rate of reoxidation of EH2 by GSSG, of the wild-type enzyme is approximately 4-fold faster than that of Y114L. These results are consistent with Tyr197 serving as a gate in the binding of NADPH, and they indicate that Tyr114 assists the acid catalyst His467'. PMID:9760231

  6. Thermal Stabilization of Dihydrofolate Reductase Using Monte Carlo Unfolding Simulations and Its Functional Consequences

    PubMed Central

    Whitney, Anna; Shakhnovich, Eugene I.

    2015-01-01

    Design of proteins with desired thermal properties is important for scientific and biotechnological applications. Here we developed a theoretical approach to predict the effect of mutations on protein stability from non-equilibrium unfolding simulations. We establish a relative measure based on apparent simulated melting temperatures that is independent of simulation length and, under certain assumptions, proportional to equilibrium stability, and we justify this theoretical development with extensive simulations and experimental data. Using our new method based on all-atom Monte-Carlo unfolding simulations, we carried out a saturating mutagenesis of Dihydrofolate Reductase (DHFR), a key target of antibiotics and chemotherapeutic drugs. The method predicted more than 500 stabilizing mutations, several of which were selected for detailed computational and experimental analysis. We find a highly significant correlation of r = 0.65–0.68 between predicted and experimentally determined melting temperatures and unfolding denaturant concentrations for WT DHFR and 42 mutants. The correlation between energy of the native state and experimental denaturation temperature was much weaker, indicating the important role of entropy in protein stability. The most stabilizing point mutation was D27F, which is located in the active site of the protein, rendering it inactive. However for the rest of mutations outside of the active site we observed a weak yet statistically significant positive correlation between thermal stability and catalytic activity indicating the lack of a stability-activity tradeoff for DHFR. By combining stabilizing mutations predicted by our method, we created a highly stable catalytically active E. coli DHFR mutant with measured denaturation temperature 7.2°C higher than WT. Prediction results for DHFR and several other proteins indicate that computational approaches based on unfolding simulations are useful as a general technique to discover stabilizing mutations. PMID:25905910

  7. Thermal stabilization of dihydrofolate reductase using monte carlo unfolding simulations and its functional consequences.

    PubMed

    Tian, Jian; Woodard, Jaie C; Whitney, Anna; Shakhnovich, Eugene I

    2015-04-01

    Design of proteins with desired thermal properties is important for scientific and biotechnological applications. Here we developed a theoretical approach to predict the effect of mutations on protein stability from non-equilibrium unfolding simulations. We establish a relative measure based on apparent simulated melting temperatures that is independent of simulation length and, under certain assumptions, proportional to equilibrium stability, and we justify this theoretical development with extensive simulations and experimental data. Using our new method based on all-atom Monte-Carlo unfolding simulations, we carried out a saturating mutagenesis of Dihydrofolate Reductase (DHFR), a key target of antibiotics and chemotherapeutic drugs. The method predicted more than 500 stabilizing mutations, several of which were selected for detailed computational and experimental analysis. We find a highly significant correlation of r = 0.65-0.68 between predicted and experimentally determined melting temperatures and unfolding denaturant concentrations for WT DHFR and 42 mutants. The correlation between energy of the native state and experimental denaturation temperature was much weaker, indicating the important role of entropy in protein stability. The most stabilizing point mutation was D27F, which is located in the active site of the protein, rendering it inactive. However for the rest of mutations outside of the active site we observed a weak yet statistically significant positive correlation between thermal stability and catalytic activity indicating the lack of a stability-activity tradeoff for DHFR. By combining stabilizing mutations predicted by our method, we created a highly stable catalytically active E. coli DHFR mutant with measured denaturation temperature 7.2°C higher than WT. Prediction results for DHFR and several other proteins indicate that computational approaches based on unfolding simulations are useful as a general technique to discover stabilizing mutations. PMID:25905910

  8. Multipyrene Tandem Probes for Point Mutations Detection in DNA

    PubMed Central

    Kholodar, Svetlana A.; Novopashina, Darya S.; Meschaninova, Mariya I.; Venyaminova, Alya G.

    2013-01-01

    Here we report design, synthesis and characterization of highly sensitive, specific and stable in biological systems fluorescent probes for point mutation detection in DNA. The tandems of 3?- and 5?-mono- and bis-pyrene conjugated oligo(2?-O-methylribonucleotides), protected by 3?-“inverted” thymidine, were constructed and their potential as new instruments for genetic diagnostics was studied. Novel probes have been shown to exhibit an ability to form stable duplexes with DNA target due to the stabilizing effect of multiple pyrene units at the junction. The relationship between fluorescent properties of developed probes, the number of pyrene residues at the tandem junction, and the location of point mutation has been studied. On the basis of the data obtained, we have chosen the probes possessing the highest fluorescence intensity along with the best mismatch discrimination and deletion and insertion detection ability. Application of developed probes for detection of polymorphism C677T in MTHFR gene has been demonstrated on model systems. PMID:24455205

  9. Resistance to antifolates in Plasmodium falciparum monitored by sequence analysis of dihydropteroate synthetase and dihydrofolate reductase alleles in a large number of field samples of diverse origins

    Microsoft Academic Search

    Ping Wang; Chung-Shinn Lee; Riad Bayoumi; Abdoulaye Djimde; Ogobara Doumbo; Göte Swedberg; Le Duc Dao; Hassan Mshinda; Marcel Tanner; William M Watkins; Paul F. G Sims; John E Hyde

    1997-01-01

    Resistance of Plasmodium falciparum to antifolate chemotherapy is a significant problem where combinations such as Fansidar (pyrimethamine–sulfadoxine; PYR–SDX) are used in the treatment of chloroquine-resistant malaria. Antifolate resistance has been associated with variant sequences of dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS), the targets of PYR and SDX respectively. However, while the nature and distribution of mutations in the dhfr

  10. Human carbonyl reductase 4 is a mitochondrial NADPH-dependent quinone reductase.

    PubMed

    Endo, Satoshi; Matsunaga, Toshiyuki; Kitade, Yukio; Ohno, Satoshi; Tajima, Kazuo; El-Kabbani, Ossama; Hara, Akira

    2008-12-26

    A protein encoded in the gene Cbr4 on human chromosome 4q32.3 belongs to the short-chain dehydrogenase/reductase family. Contrary to the functional annotation as carbonyl reductase 4 (CBR4), we show that the recombinant tetrameric protein, composed of 25-kDa subunits, exhibits NADPH-dependent reductase activity for o- and p-quinones, but not for other aldehydes and ketones. The enzyme was insensitive to dicumarol and quercetin, potent inhibitors of cytosolic quinone reductases. The 25-kDa CBR4 was detected in human liver, kidney and cell lines on Western blotting using anti-CBR4 antibodies. The overexpression of CBR4 in bovine endothelial cells reveals that the enzyme has a non-cleavable mitochondrial targeting signal. We further demonstrate that the in vitro quinone reduction by CBR4 generates superoxide through the redox cycling, and suggest that the enzyme may be involved in the induction of apoptosis by cytotoxic 9,10-phenanthrenequinone. PMID:19000905

  11. Structure and function of NADPH-cytochrome P450 reductase and nitric oxide synthase reductase domain

    SciTech Connect

    Iyanagi, Takashi [Biometal Science Laboratory, RIKEN Harima Institute/Spring8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148 (Japan)]. E-mail: iyanagi@spring8.or.jp

    2005-12-09

    NADPH-cytochrome P450 reductase (CPR) and the nitric oxide synthase (NOS) reductase domains are members of the FAD-FMN family of proteins. The FAD accepts two reducing equivalents from NADPH (dehydrogenase flavin) and FMN acts as a one-electron carrier (flavodoxin-type flavin) for the transfer from NADPH to the heme protein, in which the FMNH {sup {center_dot}}/FMNH{sub 2} couple donates electrons to cytochrome P450 at constant oxidation-reduction potential. Although the interflavin electron transfer between FAD and FMN is not strictly regulated in CPR, electron transfer is activated in neuronal NOS reductase domain upon binding calmodulin (CaM), in which the CaM-bound activated form can function by a similar mechanism to that of CPR. The oxygenated form and spin state of substrate-bound cytochrome P450 in perfused rat liver are also discussed in terms of stepwise one-electron transfer from CPR. This review provides a historical perspective of the microsomal mixed-function oxidases including CPR and P450. In addition, a new model for the redox-linked conformational changes during the catalytic cycle for both CPR and NOS reductase domain is also discussed.

  12. Pharmacogenetic evaluation of ABCB1, Cyp2C9, Cyp2C19 and methylene tetrahydrofolate reductase polymorphisms in teratogenicity of anti-epileptic drugs in women with epilepsy

    PubMed Central

    Jose, Manna; Banerjee, Moinak; Mathew, Anila; Bharadwaj, Tashi; Vijayan, Neetha; Thomas, Sanjeev V.

    2014-01-01

    Aim: Pregnancy in women with epilepsy (WWE) who are on anti-epileptic drugs (AEDs) has two- to three-fold increased risk of fetal malformations. AEDs are mostly metabolized by Cyp2C9, Cyp2C19 and Cyp3A4 and transported by ABCB1. Patients on AED therapy can have folate deficiency. We hypothesize that the polymorphisms in ABCB1, Cyp2C9, Cyp2C19 and methylene tetrahydrofolate reductase (MTHFR) might result in differential expression resulting in differential drug transport, drug metabolism and folate metabolism, which in turn may contribute to the teratogenic impact of AEDs. Materials and Methods: The ABCB1, Cyp2C9, Cyp2C19 and MTHFR polymorphisms were genotyped for their role in teratogenic potential and the nature of teratogenecity in response to AED treatment in WWE. The allelic, genotypic associations were tested in 266 WWE comprising of 143 WWE who had given birth to babies with WWE-malformation (WWE-M) and 123 WWE who had normal offsprings (WWE-N). Results: In WWE-M, CC genotype of Ex07 + 139C/T was overrepresented (P = 0.0032) whereas the poor metabolizer allele *2 and *2 *2 genotype of CYP2C219 was significantly higher in comparison to WWE-N group (P = 0.007 and P = 0.005, respectively). All these observations were independent of the nature of malformation (cardiac vs. non cardiac malformations). Conclusion: Our study indicates the possibility that ABCB1 and Cyp2C19 may play a pivotal role in the AED induced teratogenesis, which is independent of nature of malformation. This is one of the first reports indicating the pharmacogenetic role of Cyp2C19 and ABCB1 in teratogenesis of AED in pregnant WWE. PMID:25221392

  13. MTHFR 677T Is a Strong Determinant of the Degree of Hearing Loss Among Polish Males with Postlingual Sensorineural Hearing Impairment

    PubMed Central

    Pollak, Agnieszka; Mueller-Malesinska, Malgorzata; Lechowicz, Urszula; Skorka, Agata; Korniszewski, Lech; Sobczyk-Kopciol, Agnieszka; Waskiewicz, Anna; Broda, Grazyna; Iwanicka-Pronicka, Katarzyna; Oldak, Monika; Skarzynski, Henryk

    2012-01-01

    Hearing impairment (HI) is the most common sensory handicap. Congenital HI often has a genetic basis, whereas the etiology of nonsyndromic postlingual HI (npHI) usually remains unidentified. Our purpose was to test whether the MTHFR C677T (rs1801133) polymorphism affecting folate metabolism is associated with the occurrence or severity of npHI. We studied rs1801133 genotypes in 647 npHI patients (age <40, sudden sensorineural loss excluded, HI characterized as mean of better ear hearing thresholds for 0.5–8 kHz) and 3273 adult controls from the background population. Genotype distribution among patients and controls was similar, but among male cases (n=302) we found a dose-dependent correlation of MTHFR 677T with the degree of HI (mean thresholds in dB: 38.8, 44.9, and 53.3, for CC, CT, and TT genotypes, respectively; p=0.0013, pcor.=0.017). Among male patients rs1801133 TT significantly increased the risk of severe/profound HI (odds ratio=4.88, p=0.001). Among controls the known effect of MTHFR 677T on plasma total homocysteine was more pronounced in men than in women (p<0.00004 for genotype-sex interaction) suggesting that in Poland folate deficiency is more prevalent in males. In conclusion, we report a novel strong effect of MTHFR 677T among males with npHI. The functional significance of rs1801133 suggests that these patients may benefit from folate supplementation—an intervention which is simple, cheap, and devoid of side effects. PMID:22424391

  14. Polymorphisms in ERCC1, GSTs, TS and MTHFR predict clinical outcomes of gastric cancer patients treated with platinum/5-Fu-based chemotherapy: a systematic review

    PubMed Central

    2012-01-01

    Background Despite genetic polymorphism in response to platinum/5-Fu chemotherapy in gastric cancer (GC) has been studied, data reported so far are conflicting and critical consideration is needed before translation to the treatment of GC. Methods We performed a meta-analysis by using 20 eligible studies to examine polymorphisms of ERCC1, GSTs, TS and MTHFR in predicting clinical outcomes (response rate, overall survival and toxicity) of GC patients treated with platinum/5-Fu-based chemotherapy. The association was measured using random/fixed effect odds ratios (ORs) or hazard ratios (HRs) combined with their 95% confidence intervals (CIs) according to the studies’ heterogeneity. Statistical analysis was performed with the software STATA 9.0 package. Results No significant association was found between response rate and genetic polymorphism in TS, MTHFR, ERCC1, GSTM1 and GSTP1. However, response rate was higher in GSTT1 (+) genotype compared with GSTT1 (?) genotype (T-/T+: OR=0.67, 95% CI: 0.47–0.97). With regard to long term outcomes, we could observe a significant longer overall survival in TS 3R/3R [(2R2R+2R3R)/3R3R: HR=1.29, 95% CI: 1.02–1.64] and GSTP1 GG/GA [(GG+AG)/AA: HR=0.51, 95% CI: (0.39, 0.67)] genotypes. In addition, significant association was demonstrated between toxicity and genetic polymorphism in TS, MTHFR and GSTP1 in included studies. Conclusion Polymorphisms of ERCC1, GSTs, TS and MTHFR were closely associated with clinical outcomes of GC patients treated with platinum/5-Fu-based chemotherapy. Studies with large sample size using the method of multi-variant analyses may help us to give more persuasive data on the putative association in future. PMID:23020798

  15. Original Articles Cytometric Quantification of Nitrate Reductase by

    E-print Network

    Jochem, Frank J.

    Original Articles Cytometric Quantification of Nitrate Reductase by Immunolabeling in the Marine November 1999; Accepted 24 November 1999 Background: The uptake of nitrate by phytoplankton is a central of biogenic carbon. Nitrate reductase catalyzes the first step of nitrate assimilation, the reduction of NO3

  16. ORIGINAL PAPER Nitrate reductase activity and nitrogen compounds in xylem

    E-print Network

    ORIGINAL PAPER Nitrate reductase activity and nitrogen compounds in xylem exudate of Juglans nigra is limited. We fertilized 1-year-old, half-sib black walnut (Juglans nigra L.) seedlings with ammonium (NH4 Nitrate Á Nitrate reductase Á Ammonium Á Xylem exudate Introduction Black walnut (Juglans nigra L.) is one

  17. Functional and Phylogenetic Divergence of Fungal Adenylate-Forming Reductases

    PubMed Central

    Kalb, Daniel; Lackner, Gerald

    2014-01-01

    A key step in fungal l-lysine biosynthesis is catalyzed by adenylate-forming l-?-aminoadipic acid reductases, organized in domains for adenylation, thiolation, and the reduction step. However, the genomes of numerous ascomycetes and basidiomycetes contain an unexpectedly large number of additional genes encoding similar but functionally distinct enzymes. Here, we describe the functional in vitro characterization of four reductases which were heterologously produced in Escherichia coli. The Ceriporiopsis subvermispora serine reductase Nps1 features a terminal ferredoxin-NADP+ reductase (FNR) domain and thus belongs to a hitherto undescribed class of fungal multidomain enzymes. The second major class is characterized by the canonical terminal short-chain dehydrogenase/reductase domain and represented by Ceriporiopsis subvermispora Nps3 as the first biochemically characterized l-?-aminoadipic acid reductase of basidiomycete origin. Aspergillus flavus l-tyrosine reductases LnaA and LnbA are members of a distinct phylogenetic clade. Phylogenetic analysis supports the view that fungal adenylate-forming reductases are more diverse than previously recognized and belong to four distinct classes. PMID:25085485

  18. Inhibition of Disulfide Reductases as a Therapeutic Strategy

    Microsoft Academic Search

    Nadeem O. Kaakoush; George L. Mendz

    2009-01-01

    Disulfide reductases are involved in many functions in the cell, in particular, maintaining the intracellular redox balance. Many classes of these enzymes exist, and their inhibition has served as an effective therapy against different types of human diseases. The involvement of disulfide reductases in various cellular processes is reviewed, and therapeutic strategies against pathogenic bacteria, parasitic infections, and human diseases

  19. Deletion of steroid 5?-reductase 2 gene in male pseudohermaphroditism

    PubMed Central

    Andersson, Stefan; Berman, David M.; Jenkins, Elizabeth P.; Russell, David W.

    2015-01-01

    The conversion of testosterone into dihydrotestosterone by steroid 5?-reductase is a key reaction in androgen action, and is essential both for the formation of the male phenotype during embryogenesis and for androgen-mediated growth of tissues such as the prostate1,2. Single gene defects that impair this conversion lead to pseudohermaphroditism in which 46 X, Y males have male internal urogenital tracts, but female external genitalia3. We have described the isolation of a human 5?-reductase complementary DNA from prostate4. Subsequent cloning and genetic studies showed that this gene (designated 5?-reductase 1) was normal in patients with 5?-reductase deficiency26. We report here the isolation of a second 5?-reductase cDNA by expression cloning and the polymerase chain reaction. The biochemical and pharmacological properties of this cDNA-encoded enzyme (designated 5?-reductase 2) are consistent with it being the major isozyme in genital tissue. A deletion in this gene is present in two related individuals with male pseudohermaphroditism caused by 5?-reductase deficiency. These results verify the existence of at least two 5?-reductases in man and provide insight into a fundamental hormone-mediated event in male sexual differentiation. PMID:1944596

  20. Glyceraldehyde 3-Phosphate Dehydrogenases and Glyoxylate Reductase

    PubMed Central

    Cerff, R.

    1973-01-01

    The development of NADP- and NAD-dependent glyceraldehyde 3-phosphate dehydrogenase and NADH-specific glyoxylate reductase was followed in Sinapis alba cotyledons grown in the dark or under continuous red and far red light. All three enzyme activities are promoted by light, continuous far red light being more than twice as effective as continuous red light. The activities of the NADP-glyceraldehyde 3-phosphate dehydrogenase and glyoxylate reductase increase in the far red light from 36 to 96 hours. They remain constant until at least 120 hours after sowing and are respectively 11 and 6 times higher than the maximum dark activities. Contrary to this, the activity of the NAD-glyceraldehyde 3-phosphate dehydrogenase is scarcely more than doubled under continuous far red irradiation relative to its maximal dark level, and its time course curve is displaced along the time axis, with the activity increasing between 24 and 72 hours after sowing. The increase in activity of NADP-glyceraldehyde 3-phosphate dehydrogenase and glyoxylate reductase is inhibited by d-threo-chloramphenicol but not by the l-threo isomer at concentrations of 200 micrograms per milliliter or less, whereas the slight inhibitory effect of chloramphenicol on the NAD-glyceraldehyde 3-phosphate dehydrogenase is not stereospecific. The three enzyme activities are inhibited by cycloheximide. When Knop's solution is used as growth medium it strongly promotes NADP-glyceraldehyde 3-phosphate dehydrogenase activity in vivo and is twice as effective in the red light as in the far red light and dark. The activity of NAD-glyceraldehyde 3-phosphate dehydrogenase is only slightly and almost equally enhanced by Knop's solution in the dark, red, and far red light. These results are consistent with the following conclusions. [List: see text] PMID:16658301

  1. Vaccinia virus induces ribonucleotide reductase in primate cells.

    PubMed Central

    Slabaugh, M B; Johnson, T L; Mathews, C K

    1984-01-01

    Infection of monkey kidney (BSC-40) cells with vaccinia virus strain WR resulted in a marked increase in ribonucleoside diphosphate reductase (EC 1.17.4.1) activity as measured by CDP reduction in cell-free extracts. After a synchronous infection, increased activity was detected at 2 h, peaked at 4 to 5 h, and then declined between 6 and 8 h to the endogenous cellular level. The induction, detectable at 0.5 PFU/cell, correlated strongly with multiplicity of infection to 10 PFU/cell and continued to increase to 50 PFU/cell. It paralleled the previously described induction of viral DNA polymerase and thymidine kinase, suggesting that the reductase may also be a product of early transcription of the viral genome. The inhibition of DNA synthesis throughout infection resulted in prolonged accumulation of reductase activity and delayed and incomplete down-regulation at 8 h, suggesting that repression involves late functions. Rescue of fluorodeoxyuridine-inhibited DNA synthesis with exogenous thymidine restored the normal pattern. Preferential association of the induced reductase with the cytoplasmic sites of vaccinia virus DNA replication (virosomes) was not detected. The induced enzyme is similar in several respects to other eucaryotic ribonucleotide reductases, but is distinct from host cell reductase in response to certain modulators of reductase activity (M. B. Slabaugh and Christopher K. Mathews, J. Virol. 52:501-506, 1984). Full activity required an activator, exogenous reducing equivalents, and iron. Hydroxyurea, EDTA, dATP, and dTTP inhibited CDP reduction, setting this reductase apart from T4 reductase, which is not inhibited by dATP, and from herpesvirus reductase, which requires no activation and is insensitive to deoxyribonucleoside triphosphate inhibition. PMID:6387175

  2. Enhanced poly(3-hydroxybutyrate) production in transgenic tobacco BY-2 cells using engineered acetoacetyl-CoA reductase.

    PubMed

    Yokoo, Toshinori; Matsumoto, Ken'ichiro; Ooba, Takashi; Morimoto, Kenjiro; Taguchi, Seiichi

    2015-06-01

    Highly active mutant of NADPH-dependent acetoacetyl-CoA reductase (PhaB) was expressed in Nicotiana tabacum cv. Bright Yellow-2 cultured cells to produce poly(3-hydroxybutyrate) [P(3HB)]. The mutated PhaB increased P(3HB) content by three-fold over the control, indicating that the mutant was a versatile tool for P(3HB) production. Additionally, the PhaB-catalyzed reaction was suggested to be a rate-limiting step of P(3HB) biosynthesis in tobacco BY-2 cells. PMID:25647430

  3. A STD-NMR study of the interaction of the Anabaena ferredoxin-NADP+ reductase with the coenzyme.

    PubMed

    Antonini, Lara V; Peregrina, José R; Angulo, Jesús; Medina, Milagros; Nieto, Pedro M

    2014-01-01

    Ferredoxin-NADP+ reductase (FNR) catalyzes the electron transfer from ferredoxin to NADP+ via its flavin FAD cofactor. To get further insights in the architecture of the transient complexes produced during the hydride transfer event between the enzyme and the NADP+ coenzyme we have applied NMR spectroscopy using Saturation Transfer Difference (STD) techniques to analyze the interaction between FNRox and the oxidized state of its NADP+ coenzyme. We have found that STD NMR, together with the use of selected mutations on FNR and of the non-FNR reacting coenzyme analogue NAD+, are appropriate tools to provide further information about the the interaction epitope. PMID:24402199

  4. Mutation rates and mutational loads in man

    SciTech Connect

    Cavalli-Sforza, L.L.

    1984-01-01

    The following areas of research are discussed: (1) the study of human mutation rates; (2) geography of human genes and its relevance to mutation; (3) sociocultural studies correlated with population genetics; (4) consanguineous marriages; and (5) surnames. (ACR)

  5. Association of Genetic Mutations in Plasmodium vivax dhfr with Resistance to Sulfadoxine-Pyrimethamine: Geographical and Clinical Correlates

    Microsoft Academic Search

    MALLIKA IMWONG; SASITHON PUKRITTAKAYAMEE; SORNCHAI LOOAREESUWAN; GEOFFREY PASVOL; J. Poirreiz; NICHOLAS J. WHITE; GEORGES SNOUNOU

    2001-01-01

    Mutations in the Plasmodium falciparum gene (dhfr) encoding dihydrofolate reductase are associated with resistance to antifols. Plasmodium vivax, the more prevalent malaria parasite in Asia and the Americas, is considered antifol resistant. Functional polymorphisms in the dhfr gene of P. vivax (pvdhfr) were assessed by PCR-restriction fragment length polymorphism using blood samples taken from 125 patients with acute vivax malaria

  6. Biliverdin reductase: a target for cancer therapy?

    PubMed Central

    Gibbs, Peter E. M.; Miralem, Tihomir; Maines, Mahin D.

    2015-01-01

    Biliverdin reductase (BVR) is a multifunctional protein that is the primary source of the potent antioxidant, bilirubin. BVR regulates activities/functions in the insulin/IGF-1/IRK/PI3K/MAPK pathways. Activation of certain kinases in these pathways is/are hallmark(s) of cancerous cells. The protein is a scaffold/bridge and intracellular transporter of kinases that regulate growth and proliferation of cells, including PKCs, ERK and Akt, and their targets including NF-?B, Elk1, HO-1, and iNOS. The scaffold and transport functions enable activated BVR to relocate from the cytosol to the nucleus or to the plasma membrane, depending on the activating stimulus. This enables the reductase to function in diverse signaling pathways. And, its expression at the transcript and protein levels are increased in human tumors and the infiltrating T-cells, monocytes and circulating lymphocytes, as well as the circulating and infiltrating macrophages. These functions suggest that the cytoprotective role of BVR may be permissive for cancer/tumor growth. In this review, we summarize the recent developments that define the pro-growth activities of BVR, particularly with respect to its input into the MAPK signaling pathway and present evidence that BVR-based peptides inhibit activation of protein kinases, including MEK, PKC?, and ERK as well as downstream targets including Elk1 and iNOS, and thus offers a credible novel approach to reduce cancer cell proliferation.

  7. Enzyme toolbox: novel enantiocomplementary imine reductases.

    PubMed

    Scheller, Philipp N; Fademrecht, Silvia; Hofelzer, Sebastian; Pleiss, Jürgen; Leipold, Friedemann; Turner, Nicholas J; Nestl, Bettina M; Hauer, Bernhard

    2014-10-13

    Reducing reactions are among the most useful transformations for the generation of chiral compounds in the fine-chemical industry. Because of their exquisite selectivities, enzymatic approaches have emerged as the method of choice for the reduction of C=O and activated C=C bonds. However, stereoselective enzymatic reduction of C=N bonds is still in its infancy-it was only recently described after the discovery of enzymes capable of imine reduction. In our work, we increased the spectrum of imine-reducing enzymes by database analysis. By combining the currently available knowledge about the function of imine reductases with the experimentally uncharacterized diversity stored in protein sequence databases, three novel imine reductases with complementary enantiopreference were identified along with amino acids important for catalysis. Furthermore, their reducing capability was demonstrated by the reduction of the pharmaceutically relevant prochiral imine 2-methylpyrroline. These novel enzymes exhibited comparable to higher catalytic efficiencies than previously described enzymes, and their biosynthetic potential is highlighted by the full conversion of 2-methylpyrroline in whole cells with excellent selectivities. PMID:25163890

  8. Impact of residues remote from the catalytic centre on enzyme catalysis of copper nitrite reductase

    PubMed Central

    Leferink, Nicole G. H.; Antonyuk, Svetlana V.; Houwman, Joseline A.; Scrutton, Nigel S.; Eady, Robert R.; Hasnain, S. Samar

    2014-01-01

    Enzyme mechanisms are often probed by structure-informed point mutations and measurement of their effects on enzymatic properties to test mechanistic hypotheses. In many cases, the challenge is to report on complex, often inter-linked elements of catalysis. Evidence for long-range effects on enzyme mechanism resulting from mutations remains sparse, limiting the design/redesign of synthetic catalysts in a predictable way. Here we show that improving the accessibility of the active site pocket of copper nitrite reductase by mutation of a surface-exposed phenylalanine residue (Phe306), located 12?Å away from the catalytic site type-2 Cu (T2Cu), profoundly affects intra-molecular electron transfer, substrate-binding and catalytic activity. Structures and kinetic studies provide an explanation for the lower affinity for the substrate and the alteration of the rate-limiting step in the reaction. Our results demonstrate that distant residues remote from the active site can have marked effects on enzyme catalysis, by driving mechanistic change through relatively minor structural perturbations. PMID:25022223

  9. Isolation of sulfite reductase variants of a commercial wine yeast with significantly reduced hydrogen sulfide production.

    PubMed

    Cordente, Antonio G; Heinrich, Anthony; Pretorius, Isak S; Swiegers, Jan H

    2009-05-01

    The production of hydrogen sulfide (H(2)S) during fermentation is a common and significant problem in the global wine industry as it imparts undesirable off-flavors at low concentrations. The yeast Saccharomyces cerevisiae plays a crucial role in the production of volatile sulfur compounds in wine. In this respect, H(2)S is a necessary intermediate in the assimilation of sulfur by yeast through the sulfate reduction sequence with the key enzyme being sulfite reductase. In this study, we used a classical mutagenesis method to develop and isolate a series of strains, derived from a commercial diploid wine yeast (PDM), which showed a drastic reduction in H(2)S production in both synthetic and grape juice fermentations. Specific mutations in the MET10 and MET5 genes, which encode the catalytic alpha- and beta-subunits of the sulfite reductase enzyme, respectively, were identified in six of the isolated strains. Fermentations with these strains indicated that, in comparison with the parent strain, H(2)S production was reduced by 50-99%, depending on the strain. Further analysis of the wines made with the selected strains indicated that basic chemical parameters were similar to the parent strain except for total sulfite production, which was much higher in some of the mutant strains. PMID:19236486

  10. Hydroxylated naphthoquinones as substrates for Escherichia coli anaerobic reductases.

    PubMed Central

    Rothery, R A; Chatterjee, I; Kiema, G; McDermott, M T; Weiner, J H

    1998-01-01

    We have used two hydroxylated naphthoquinol menaquinol analogues, reduced plumbagin (PBH2, 5-hydroxy-2-methyl-1,4-naphthoquinol) and reduced lapachol [LPCH2, 2-hydroxy-3-(3-methyl-2-butenyl)-1, 4-naphthoquinol], as substrates for Escherichia coli anaerobic reductases. These compounds have optical, solubility and redox properties that make them suitable for use in studies of the enzymology of menaquinol oxidation. Oxidized plumbagin and oxidized lapachol have well resolved absorbances at 419 nm (epsilon=3.95 mM-1. cm-1) and 481 nm (epsilon=2.66 mM-1.cm-1) respectively (in Mops/KOH buffer, pH 7.0). PBH2 is a good substrate for nitrate reductase A (Km=282+/-28 microM, kcat=120+/-6 s-1) and fumarate reductase (Km=155+/-24 microM, kcat=30+/-2 s-1), but not for DMSO reductase. LPCH2 is a good substrate for nitrate reductase A (Km=57+/-35 microM, kcat=68+/-13 s-1), fumarate reductase (Km=85+/-27 microM, kcat=74+/-6 s-1) and DMSO reductase (Km=238+/-30 microM, kcat=191+/-21 s-1). The sensitivity of enzymic LPCH2 and PBH2 oxidation to 2-n-heptyl-4-hydroxyquinoline N-oxide inhibition is consistent with their oxidation occurring at sites of physiological quinol binding. PMID:9576848

  11. Identification of the missing trans-acting enoyl reductase required for phthiocerol dimycocerosate and phenolglycolipid biosynthesis in Mycobacterium tuberculosis.

    PubMed

    Siméone, Roxane; Constant, Patricia; Guilhot, Christophe; Daffé, Mamadou; Chalut, Christian

    2007-07-01

    Phthiocerol dimycocerosates (DIM) and phenolglycolipids (PGL) are functionally important surface-exposed lipids of Mycobacterium tuberculosis. Their biosynthesis involves the products of several genes clustered in a 70-kb region of the M. tuberculosis chromosome. Among these products is PpsD, one of the modular type I polyketide synthases responsible for the synthesis of the lipid core common to DIM and PGL. Bioinformatic analyses have suggested that this protein lacks a functional enoyl reductase activity domain required for the synthesis of these lipids. We have identified a gene, Rv2953, that putatively encodes an enoyl reductase. Mutation in Rv2953 prevents conventional DIM formation and leads to the accumulation of a novel DIM-like product. This product is unsaturated between C-4 and C-5 of phthiocerol. Consistently, complementation of the mutant with a functional pks15/1 gene from Mycobacterium bovis BCG resulted in the accumulation of an unsaturated PGL-like substance. When an intact Rv2953 gene was reintroduced into the mutant strain, the phenotype reverted to the wild type. These findings indicate that Rv2953 encodes a trans-acting enoyl reductase that acts with PpsD in phthiocerol and phenolphthiocerol biosynthesis. PMID:17468241

  12. Towards the Understanding of Resistance Mechanisms in Clinically Isolated Trimethoprim-resistant, Methicillin-resistant Staphylococcus aureus Dihydrofolate Reductase

    SciTech Connect

    Frey, K.; Lombardo, M; Wright, D; Anderson, A

    2010-01-01

    Resistance to therapeutics such as trimethoprim-sulfamethoxazole has become an increasing problem in strains of methicillin-resistant Staphylococcus aureus (MRSA). Clinically isolated trimethoprim-resistant strains reveal a double mutation, H30N/F98Y, in dihydrofolate reductase (DHFR). In order to develop novel and effective therapeutics against these resistant strains, we evaluated a series of propargyl-linked antifolate lead compounds for inhibition of the mutant enzyme. For the propargyl-linked antifolates, the F98Y mutation generates minimal (between 1.2- and 6-fold) losses of affinity and the H30N mutation generates greater losses (between 2.4- and 48-fold). Conversely, trimethoprim affinity is largely diminished by the F98Y mutation (36-fold) and is not affected by the H30N mutation. In order to elucidate a mechanism of resistance, we determined a crystal structure of a complex of this double mutant with a lead propargyl-linked antifolate. This structure suggests a resistance mechanism consistent both for the propargyl-linked class of antifolates and for trimethoprim that is based on the loss of a conserved water-mediated hydrogen bond.

  13. Solubilization and Resolution of the Membrane-Bound Nitrite Reductase from Paracoccus Halodenitrificans into Nitrite and Nitric Oxide Reductases

    NASA Technical Reports Server (NTRS)

    Grant, Michael A.; Cronin, Sonja E.; Hochstein, Lawrence I.

    1984-01-01

    Membranes prepared from Paracoccus halodenitrificans reduced nitrite or nitric oxide to nitrous oxide. Extraction of these membranes with the detergent CHAPSO [3-(3-Chlolamidoporopyldimethylammonio)-1-(2- hydroxy-1-propanesulfonate)], followed by ammonium sulfate fractionation of the solubilized proteins, resulted in the separation of nitrite and nitric oxide reductase activities. The fraction containing nitrite reductase activity spectrally resembled a cd-type cytochrome. Several cytochromes were detected in the nitric oxide reductase fraction. Which, if any, of these cytochromes is associated with the reduction of nitric oxide is not clear at this time.

  14. Genetic variation in the folate metabolic pathway and risk of childhood leukemia Tracy J Lightfoot1

    E-print Network

    California at Berkeley, University of

    the association between polymorphisms in key folate metabolism enzymes (MTHFR677 C>T, MTHFR1298 A>C, SHMT11420 C were used for comparison. No evidence of an association with MTHFR677 was observed for ALL or AML metabolic pathway is methylene tetrahydrofolate reductase (MTHFR) which controls the balance between DNA

  15. Structural and mechanistic mapping of a unique fumarate reductase 

    E-print Network

    Taylor, Paul; Pealing, Sara L; Reid, Graeme A; Chapman, Stephen K; Walkinshaw, Malcolm

    The 1.8 Å resolution crystal structure of the tetraheme flavocytochrome c3, Fcc3, provides the first mechanistic insight into respiratory fumarate reductases or succinate dehydrogenases. The multi-redox center, three-domain ...

  16. Regulation of Nitrate Reductase in Excised Barley Roots 1

    PubMed Central

    Smith, F. W.; Thompson, John F.

    1971-01-01

    When excised barley roots (Hordeum distichum L.) are appropriately pretreated, the level of nitrate reductase in the roots increases upon exposure to nitrate. Relatively low levels of nitrate (10 ?m) gave maximum induction of nitrate reductase. This increase was inhibited by inhibitors of protein and RNA synthesis, indicating that de novo protein synthesis is probably involved. Induction of nitrate reductase by nitrate is partially prevented by the inclusion of ammonium, an eventual product of nitrate reduction, in the incubation medium. Under the experimental conditions used, ammonium did not inhibit the uptake of nitrate by excised barley roots. It is concluded, therefore, that ammonium, or a product of ammonium metabolism, has a direct effect on the synthesis of nitrate reductase in this tissue. PMID:16657766

  17. DATABASE Open Access SORGOdb: Superoxide Reductase Gene Ontology

    E-print Network

    Paris-Sud XI, Université de

    anaerobic microbes, require oxygen. O2 is used as a substrate by many enzymes involved metabolizing amines fortuitously by fla- voenzymes such as NADH dehydrogenase II, succinate dehydrogenase, fumarate reductase

  18. 21 CFR 864.7375 - Glutathione reductase assay.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7375 Glutathione reductase assay. (a) Identification....

  19. 21 CFR 864.7375 - Glutathione reductase assay.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7375 Glutathione reductase assay. (a) Identification....

  20. 21 CFR 864.7375 - Glutathione reductase assay.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7375 Glutathione reductase assay. (a) Identification....

  1. COMPARISON OF THE METHYL REDUCTASE GENES AND GENE PRODUCTS

    EPA Science Inventory

    The DNA sequences encoding component C of methyl coenzyme M reductase (mcr genes) in Methanothermus fervidus, Methanobacterium thermoautotrophicum, Methanococcus vannielii, and Methanosarcina barkeri have been published. omparisons of transcription initiation and termination site...

  2. Thrombophilic genetic factors PAI-1 4G-4G and MTHFR 677TT as risk factors of alcohol, cryptogenic liver cirrhosis and portal vein thrombosis, in a Caucasian population.

    PubMed

    D'Amico, Mario; Pasta, Francesca; Pasta, Linda

    2015-08-15

    The thrombophilic genetic factors (THRGFs), PAI-1 4G-4G, MTHFR 677TT, V Leiden 506Q and Prothrombin 20210A, were studied as risk factors in 865 Caucasian patients with liver cirrhosis, consecutively enrolled from June 2008 to January 2014. A total of 582 HCV, 80 HBV, 94 alcohol, (82 with more than one etiologic factor) and 191 cryptogenic patients with liver cirrhosis had been consecutively enrolled; 243 patients showed portal vein thrombosis (PVT). At least one of the above THRGFs was present in 339/865 patients (39.2%). PAI-1 4G-4G and MTHFR 677TT were the most frequent THRGFs, statistically significant in patients with alcohol, cryptogenic liver cirrhosis, and PVT: respectively 24 and 28, 50 and 73, and 65 and 83 (all chi-square tests>3.84, and p values<0.05). Two logistic regression analysis, using PAI-1 4G-4G and MTHFR 677TT, as dependent variable, confirmed the independent significant relationship of these THRGFs with alcohol, cryptogenic liver cirrhosis and PVT. PAI 1 and MTHFR 677 genotypes, deviated from those expected in populations in Hardy-Weinberg equilibrium (all p values<0.05), in the subgroups of patients with alcohol, cryptogenic liver cirrhosis and presence of PVT. Our study shows the pivotal role of PAI-1 4G-4G and MTHFR 677TT in patients with alcohol, cryptogenic liver cirrhosis, and PVT, in a Caucasian population. In conclusion, thrombo and fibro-genetic mechanisms of PAI-1 4G-4G and MTHFR 677TT, could have a role in the development of liver cirrhosis, mainly in patients without HCV and HBV, and PVT. PMID:25987440

  3. Sepiapterin reductase expression is increased in Parkinson's disease brain tissue

    Microsoft Academic Search

    Jennifer E. Tobin; Jing Cui; Jemma B. Wilk; Jeanne C. Latourelle; Jason M. Laramie; Ann C. McKee; Mark Guttman; Samer Karamohamed; Anita L. DeStefano; Richard H. Myers

    2007-01-01

    The PARK3 locus on chromosome 2p13 has shown linkage to both the development and age of onset of Parkinson's disease (PD). One candidate gene at this locus is sepiapterin reductase (SPR). Sepiapterin reductase catalyzes the final step in the biosynthetic pathway of tetrahydrobiopterin (BH4), an essential cofactor for aromatic amino acid hydrolases including tyrosine hydroxylase, the rate-limiting enzyme in dopamine

  4. Characterization of a soluble ferric reductase from Neisseria gonorrhoeae

    Microsoft Academic Search

    Alain E. Le Faou; Stephen A. Morse

    1991-01-01

    Summary An NADH-dependent ferric reductase was identified in extracts ofNeisseria gonorrhoeae. Enzyme activity was measured in an assay using ferrozine as the ferrous iron acceptor. Ferric reductase activity was enhanced by Mg2+ and flavine nucleotides. The enzyme reduced both citrate- and diphosphate-bound ferric iron as well as ferric hydroxide (Imferon). However, no activity was observed with either 30%-iron-saturated transferrin or

  5. Bioautographic visualization of dihydrofolate reductase in enzyme overproducing BHK mutants

    Microsoft Academic Search

    S. L. Naylor; J. K. Townsend; R. J. Klebe

    1980-01-01

    A bioautographic procedure has been developed for the visualization of the isozymes of dihydrofolate reductase (DHFR, E.C. 1.5.1.3). In addition to detecting electrophoretically separated enzymes, bioautography was utilized to visualize DHFR after isoelectric focusing on polyacrylamide gels. Both zone electrophoresis and isoelectric focusing were used to compare wildtype BHK cells to mutants which overproduce dihydrofolate reductase. In agreement with other

  6. Folic Acid Supplementation Use and the MTHFR C677T Polymorphism in Orofacial Clefts Etiology: An Individual Participant Data Pooled-Analysis

    PubMed Central

    Butali, Azeez; Little, Julian; Chevrier, Cécile; Cordier, Sylvian; Steegers-Theunissen, Regine; Jugessur, Astanand; Oladugba, Bola; Mossey, Peter A.

    2013-01-01

    Background This study examines gene-environment interaction (GEI) between the MTHFR C667T polymorphism and folic acid in the etiology of orofacial clefts (OFC). We used a pooled-analyticapproach on four studies that used similar methods. Methods We used logistic regression to analyse the pooled sample of 1149 isolated cases and 1161 controls. Fetal and maternal MTHFR C677T genotypes, and maternal periconceptional exposure to smoking, alcohol, vitamin containing folic acid and folic acid supplements were contrasted between the cleft types [non-syndromic clefts lip or without cleft palate (CL(P)) and non syndromic cleft palate (CP)] and control groups. Results There was a reduced risk of CL(P) with maternal folic acid use (p=0.008; OR=0.70, 95% CI: 0.65–0.94) and with supplements containing folic acid (p=0.028, OR=0.80, 95% CI: 0.65–0.94). Maternal smoking increased the risk of both CL(P) (p<10e?3; OR=1.62, 95% CI: 1.35–1.95) and CP (p=0.028; OR=1.38, 95% CI: 1.04–1.83). No significant risk was observed with either maternal or fetal MTHFR C677T genotypes. Conclusion This individual paticipant data (IPD) meta-analysis affords greater statistical power and can help alleviate the problems associated with aggregate-level data-sharing. The result of this IPD meta-analysis is consistent with previous reports suggesting that folic acid and smoking influence OFC outcomes. PMID:23670871

  7. Short Communication Risk of NonHodgkin Lymphoma Associated with

    E-print Network

    California at Berkeley, University of

    studied include methylenetetra- hydrofolate reductase (MTHFR) 677 C>T and 1298 A>C, methionine synthase, 0.96-2.2). We observed no association between NHL and haplotypes for MTHFR or TYMS. These findings). Methylenetetrahydrofolate reductase (MTHFR) catalyzes the irreversible conversion of 5,10-methylenetetrahydrofolate (5,10-Me

  8. Carbonyl reductase 1 is a predominant doxorubicin reductase in the human liver.

    PubMed

    Kassner, Nina; Huse, Klaus; Martin, Hans-Jörg; Gödtel-Armbrust, Ute; Metzger, Annegret; Meineke, Ingolf; Brockmöller, Jürgen; Klein, Kathrin; Zanger, Ulrich M; Maser, Edmund; Wojnowski, Leszek

    2008-10-01

    A first step in the enzymatic disposition of the antineoplastic drug doxorubicin (DOX) is the reduction to doxorubicinol (DOX-OL). Because DOX-OL is less antineoplastic but more cardiotoxic than the parent compound, the individual rate of this reaction may affect the antitumor effect and the risk of DOX-induced heart failure. Using purified enzymes and human tissues we determined enzymes generating DOX-OL and interindividual differences in their activities. Human tissues express at least two DOX-reducing enzymes. High-clearance organs (kidney, liver, and the gastrointestinal tract) express an enzyme with an apparent Km of approximately 140 microM. Of six enzymes found to reduce DOX, Km values in this range are exhibited by carbonyl reductase 1 (CBR1) and aldo-keto reductase (AKR) 1C3. CBR1 is expressed in these three organs at higher levels than AKR1C3, whereas AKR1C3 has higher catalytic efficiency. However, inhibition constants for DOX reduction with 4-amino-1-tert-butyl-3-(2-hydroxyphenyl)pyrazolo[3,4-d]pyrimidine (an inhibitor that can discriminate between CBR1 and AKR1C3) were identical for CBR1 and human liver cytosol, but not for AKR1C3. These results suggest that CBR1 is a predominant hepatic DOX reductase. In cytosols from 80 human livers, the expression level of CBR1 and the activity of DOX reduction varied >70- and 22-fold, respectively, but showed no association with CBR1 gene variants found in these samples. Instead, the interindividual differences in CBR1 expression and activity may be mediated by environmental factors acting via recently identified xenobiotic response elements in the CBR1 promoter. The variability in the CBR1 expression may affect outcomes of therapies with DOX, as well as with other CBR1 substrates. PMID:18635746

  9. Significance of Four Methionine Sulfoxide Reductases in Staphylococcus aureus

    PubMed Central

    Singh, Vineet K.; Vaish, Manisha; Johansson, Trintje R.; Baum, Kyle R.; Ring, Robert P.; Singh, Saumya; Shukla, Sanjay K.; Moskovitz, Jackob

    2015-01-01

    Staphylococcus aureus is a major human pathogen and emergence of antibiotic resistance in clinical staphylococcal isolates raises concerns about our ability to control these infections. Cell wall-active antibiotics cause elevated synthesis of methionine sulfoxide reductases (Msrs: MsrA1 and MsrB) in S. aureus. MsrA and MsrB enzymes reduce S-epimers and R-epimers of methionine sulfoxide, respectively, that are generated under oxidative stress. In the S. aureus chromosome, there are three msrA genes (msrA1, msrA2 and msrA3) and one msrB gene. To understand the precise physiological roles of Msr proteins in S. aureus, mutations in msrA1, msrA2 and msrA3 and msrB genes were created by site-directed mutagenesis. These mutants were combined to create a triple msrA (msrA1, msrA2 and msrA3) and a quadruple msrAB (msrA1, msrA2, msrA3, msrB) mutant. These mutants were used to determine the roles of Msr proteins in staphylococcal growth, antibiotic resistance, adherence to human lung epithelial cells, pigment production, and survival in mice relative to the wild-type strains. MsrA1-deficient strains were sensitive to oxidative stress conditions, less pigmented and less adherent to human lung epithelial cells, and showed reduced survival in mouse tissues. In contrast, MsrB-deficient strains were resistant to oxidants and were highly pigmented. Lack of MsrA2 and MsrA3 caused no apparent growth defect in S. aureus. In complementation experiments with the triple and quadruple mutants, it was MsrA1 and not MsrB that was determined to be critical for adherence and phagocytic resistance of S. aureus. Overall, the data suggests that MsrA1 may be an important virulence factor and MsrB probably plays a balancing act to counter the effect of MsrA1 in S. aureus. PMID:25680075

  10. The catalytic mechanism of NADH-dependent reduction of 9,10-phenanthrenequinone by Candida tenuis xylose reductase reveals plasticity in an aldo-keto reductase active site.

    PubMed

    Pival, Simone L; Klimacek, Mario; Nidetzky, Bernd

    2009-07-01

    Despite their widely varying physiological functions in carbonyl metabolism, AKR2B5 (Candida tenuis xylose reductase) and many related enzymes of the aldo-keto reductase protein superfamily utilise PQ (9,10-phenanthrenequinone) as a common in vitro substrate for NAD(P)H-dependent reduction. The catalytic roles of the conserved active-site residues (Tyr51, Lys80 and His113) of AKR2B5 in the conversion of the reactive alpha-dicarbonyl moiety of PQ are not well understood. Using wild-type and mutated (Tyr51, Lys80 and His113 individually replaced by alanine) forms of AKR2B5, we have conducted steady-state and transient kinetic studies of the effects of varied pH and deuterium isotopic substitutions in coenzyme and solvent on the enzymatic rates of PQ reduction. Each mutation caused a 10(3)-10(4)-fold decrease in the rate constant for hydride transfer from NADH to PQ, whose value in the wild-type enzyme was determined as approximately 8 x 10(2) s(-1). The data presented support an enzymic mechanism in which a catalytic proton bridge from the protonated side chain of Lys80 (pK=8.6+/-0.1) to the carbonyl group adjacent to the hydride acceptor carbonyl facilitates the chemical reaction step. His113 contributes to positioning of the PQ substrate for catalysis. Contrasting its role as catalytic general acid for conversion of the physiological substrate xylose, Tyr51 controls release of the hydroquinone product. The proposed chemistry of AKR2B5 action involves delivery of both hydrogens required for reduction of the alpha-dicarbonyl substrate to the carbonyl group undergoing (stereoselective) transformation. Hydride transfer from NADH probably precedes the transfer of a proton from Tyr51 whose pK of 7.3+/-0.3 in the NAD+-bound enzyme appears suitable for protonation of a hydroquinone anion (pK=8.8). These results show that the mechanism of AKR2B5 is unusually plastic in the exploitation of the active-site residues, for the catalytic assistance provided to carbonyl group reduction in alpha-dicarbonyls differs from that utilized in the conversion of xylose. PMID:19368528

  11. Aldose reductase inhibitors of plant origin.

    PubMed

    Veeresham, Ciddi; Rama Rao, Ajmeera; Asres, Kaleab

    2014-03-01

    Diabetic complications are attributed to hyperglycaemic condition which is in turn associated with the polyol pathway and advanced glycation end products. Aldose reductase (AR) is the principal enzyme of polyol pathway which plays a vital role in the development of diabetic complications. AR inhibitory activity can be screened by both in vitro and in vivo methods. In vitro assays for AR enzyme are further classified on the basis of the source of enzyme such as rat lens, rat kidney, cataracted human eye lens, bovine eyes and human recombinant AR enzymes, whereas the in vivo model is based on the determination of lens galactitol levels. A number of synthetic AR inhibitors (ARIs) including tolrestat and sorbinil have been developed, but all of these suffer from drawbacks such as poor permeation and safety issues. Therefore, pharmaceutical companies and many researchers have been carrying out research to find new, potent and safe ARIs from natural sources. Thus, many naturally occurring compounds have been reported to have AR inhibitory activity. The present review attempts to highlight phytochemicals and plant extracts with potential AR inhibitory activity. It also summarizes the classes of compounds which have proven AR inhibitory activity. Phytochemicals such as quercetin, kaempferol and ellagic acid are found to be the most promising ARIs. The exhaustive literature presented in this article clearly indicates the role of plant extracts and phytochemicals as potential ARIs. PMID:23674239

  12. Aldose Reductase, Oxidative Stress, and Diabetic Mellitus

    PubMed Central

    Tang, Wai Ho; Martin, Kathleen A.; Hwa, John

    2012-01-01

    Diabetes mellitus (DM) is a complex metabolic disorder arising from lack of insulin production or insulin resistance (Diagnosis and classification of diabetes mellitus, 2007). DM is a leading cause of morbidity and mortality in the developed world, particularly from vascular complications such as atherothrombosis in the coronary vessels. Aldose reductase (AR; ALR2; EC 1.1.1.21), a key enzyme in the polyol pathway, catalyzes nicotinamide adenosine dinucleotide phosphate-dependent reduction of glucose to sorbitol, leading to excessive accumulation of intracellular reactive oxygen species (ROS) in various tissues of DM including the heart, vasculature, neurons, eyes, and kidneys. As an example, hyperglycemia through such polyol pathway induced oxidative stress, may have dual heart actions, on coronary blood vessel (atherothrombosis) and myocardium (heart failure) leading to severe morbidity and mortality (reviewed in Heather and Clarke, 2011). In cells cultured under high glucose conditions, many studies have demonstrated similar AR-dependent increases in ROS production, confirming AR as an important factor for the pathogenesis of many diabetic complications. Moreover, recent studies have shown that AR inhibitors may be able to prevent or delay the onset of cardiovascular complications such as ischemia/reperfusion injury, atherosclerosis, and atherothrombosis. In this review, we will focus on describing pivotal roles of AR in the pathogenesis of cardiovascular diseases as well as other diabetic complications, and the potential use of AR inhibitors as an emerging therapeutic strategy in preventing DM complications. PMID:22582044

  13. Periplasmic methacrylate reductase activity in Wolinella succinogenes.

    PubMed

    Gross, R; Simon, J; Kröger, A

    2001-10-01

    The cell homogenate and the soluble cell fraction of Wolinella succinogenes grown with formate and fumarate catalyzed the oxidation of benzyl viologen radical by methacrylate [apparent Km=0.23 mM, Vmax=1.0 U (mg cell protein) -1] or acrylate [apparent Km=0.50 mM, Vmax=0.77 U (mg cell protein) -1]. Crotonate did not serve as an oxidant. A mutant of W. succinogenes lacking the fccABC operon was unable to catalyze methacrylate or acrylate reduction. In contrast, the inactivation of fccC alone had no effect on these activities. Methacrylate reduction by benzyl viologen radical was not catalyzed by fumarate reductase isolated from the membrane of W. succinogenes. Cells grown with formate and fumarate did not catalyze methacrylate reduction by formate, and W. succinogenes did not grow with formate and methacrylate as catabolic substrates. The results suggest that the reduction of methacrylate or acrylate by benzyl viologen radical is most likely catalyzed either by the periplasmic flavoprotein FccA or by a complex consisting of FccA and the predicted c-type cytochrome FccB. The metabolic function of the fccABC operon remains unknown. PMID:11685377

  14. Mutation accumulation in Tetrahymena

    Microsoft Academic Search

    Patrícia H Brito; Elsa Guilherme; Helena Soares; Isabel Gordo

    2010-01-01

    BACKGROUND: The rate and fitness effects of mutations are key in understanding the evolution of every species. Traditionally, these parameters are estimated in mutation accumulation experiments where replicate lines are propagated in conditions that allow mutations to randomly accumulate without the purging effect of natural selection. These experiments have been performed with many model organisms but we still lack empirical

  15. Wolinella succinogenes quinol:fumarate reductase and its comparison to E. coli succinate:quinone reductase.

    PubMed

    Lancaster, C Roy D

    2003-11-27

    The three-dimensional structure of Wolinella succinogenes quinol:fumarate reductase (QFR), a dihaem-containing member of the superfamily of succinate:quinone oxidoreductases (SQOR), has been determined at 2.2 A resolution by X-ray crystallography [Lancaster et al., Nature 402 (1999) 377-385]. The structure and mechanism of W. succinogenes QFR and their relevance to the SQOR superfamily have recently been reviewed [Lancaster, Adv. Protein Chem. 63 (2003) 131-149]. Here, a comparison is presented of W. succinogenes QFR to the recently determined structure of the mono-haem containing succinate:quinone reductase from Escherichia coli [Yankovskaya et al., Science 299 (2003) 700-704]. In spite of differences in polypeptide and haem composition, the overall topology of the membrane anchors and their relative orientation to the conserved hydrophilic subunits is strikingly similar. A major difference is the lack of any evidence for a 'proximal' quinone site, close to the hydrophilic subunits, in W. succinogenes QFR. PMID:14630313

  16. Isolation and Characterization of cDNAs Encoding Leucoanthocyanidin Reductase and Anthocyanidin Reductase from Populus trichocarpa

    PubMed Central

    Lu, Wanxiang; Yang, Li; Karim, Abdul; Luo, Keming

    2013-01-01

    Proanthocyanidins (PAs) contribute to poplar defense mechanisms against biotic and abiotic stresses. Transcripts of PA biosynthetic genes accumulated rapidly in response to infection by the fungus Marssonina brunnea f.sp. multigermtubi, treatments of salicylic acid (SA) and wounding, resulting in PA accumulation in poplar leaves. Anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) are two key enzymes of the PA biosynthesis that produce the main subunits: (+)-catechin and (?)-epicatechin required for formation of PA polymers. In Populus, ANR and LAR are encoded by at least two and three highly related genes, respectively. In this study, we isolated and functionally characterized genes PtrANR1 and PtrLAR1 from P. trichocarpa. Phylogenetic analysis shows that Populus ANR1 and LAR1 occurr in two distinct phylogenetic lineages, but both genes have little difference in their tissue distribution, preferentially expressed in roots. Overexpression of PtrANR1 in poplar resulted in a significant increase in PA levels but no impact on catechin levels. Antisense down-regulation of PtrANR1 showed reduced PA accumulation in transgenic lines, but increased levels of anthocyanin content. Ectopic expression of PtrLAR1 in poplar positively regulated the biosynthesis of PAs, whereas the accumulation of anthocyanin and flavonol was significantly reduced (P<0.05) in all transgenic plants compared to the control plants. These results suggest that both PtrANR1 and PtrLAR1 contribute to PA biosynthesis in Populus. PMID:23741362

  17. Meta-analysis of plasma homocysteine, serum folate, serum vitamin B 12, and thermolabile MTHFR genotype as risk factors for retinal vascular occlusive disease

    Microsoft Academic Search

    Mark T Cahill; Sandra S Stinnett; Sharon Fekrat

    2003-01-01

    PurposeTo assess the role of plasma total homocysteine (tHcy) levels, serum folate and vitamin B12levels, and homozygosity for the thermolabile methylenetetrahydrofolate reductase genotype (TT) as risk factors for retinal vascular occlusive disease.

  18. VDAC1 is a transplasma membrane NADH-ferricyanide reductase.

    PubMed

    Baker, Mark A; Lane, Darius J R; Ly, Jennifer D; De Pinto, Vito; Lawen, Alfons

    2004-02-01

    Porin isoform 1 or VDAC (voltage-dependent anion-selective channel) 1 is the predominant protein in the outer mitochondrial membrane. We demonstrated previously that a plasma membrane NADH-ferricyanide reductase activity becomes up-regulated upon mitochondrial perturbation, and therefore suggested that it functions as a cellular redox sensor. VDAC1 is known to be expressed in the plasma membrane; however, its function there remained a mystery. Here we show that VDAC1, when expressed in the plasma membrane, functions as a NADH-ferricyanide reductase. VDAC1 preparations purified from both plasma membrane and mitochondria fractions exhibit NADH-ferricyanide reductase activity, which can be immunoprecipitated with poly- and monoclonal antibodies directed against VDAC(1). Transfecting cells with pl-VDAC1-GFP, which carries an N-terminal signal peptide, directs VDAC1 to the plasma membrane, as shown by confocal microscopy and FACS analysis, and significantly increases the plasma membrane NADH-ferricyanide reductase activity of the transfected cells. This novel enzymatic activity of the well known VDAC1 molecule may provide an explanation for its role in the plasma membrane. Our data suggest that a major function of VDAC1 in the plasma membrane is that of a NADH(-ferricyanide) reductase that may be involved in the maintenance of cellular redox homeostasis. PMID:14573604

  19. Escherichia coli ribonucleotide reductase expression is cell cycle regulated.

    PubMed Central

    Sun, L; Fuchs, J A

    1992-01-01

    The expression of the genes encoding ribonucleotide reductase in Escherichia coli was investigated in cultures synchronized by obtaining the smallest cells in a population after sucrose gradient centrifugation. Specific activity of ribonucleotide reductase and DNA initiation were found to increase in parallel, periodically as a function of the cell cycle. The expression of nrd was also determined in cells synchronized by periodic repeated doubling in a phosphate limited medium. Antibodies directed against the B2 subunit of ribonucleotide reductase were raised in a rabbit and purified. Immunoprecipitation of the B2 subunit and RNA-DNA dot blot hybridization assays were developed and employed to determine the expression of ribonucleotide reductase translational and transcriptional products during the cell cycle. Both of nrd-mRNA and B2 subunit expression were found to increase each generation at approximately the same time DNA synthesis was initiated and then to decrease back to the basal level shortly after DNA initiation. These results provided evidence of cell cycle dependent regulation of ribonucleotide reductase in E. coli. When the upstream regulatory region of nrd was fused to a promoterless lacZ gene on a single copy plasmid, lac-mRNA and beta-galactosidase were found to be synthesized in parallel to nrd expression from the chromosomal operon. When nrd sequences surrounding the promoter were removed from this construct, lac-mRNA and beta-galactosidase synthesis were no longer cell cycle regulated. Images PMID:1384814

  20. Characterization of a Thermolabile Sulfite Reductase from Salmonella pullorum1

    PubMed Central

    Hoeksema, Walter D.; Schoenhard, Delbert E.

    1971-01-01

    The biochemical basis for sulfite accumulation by sulfate-using revertants of Salmonella pullorum was determined. All of the sulfate-using mutants isolated from wild-type S. pullorum accumulated sulfite when grown at 37 but not at 25 C. The specific activity of reduced nicotinamide adenine dinucleotide (NADPH)-dependent sulfite reductase (H 2S-NADP oxidoreductase, EC 1.8.1.2) and of reduced methyl viologen (MVH)-dependent sulfite reductase (H 2S-MV oxidoreductase), in extracts prepared from cells incubated at 37 C, declined as the incubation period lengthened. However, the specific activity of both reductases from cells incubated at 25 C did not decline. Thermolability of cell-free NADPH-dependent sulfite reductase from cells of S. pullorum incubated at 37 C was greater than the lability of this enzyme either from cells of S. typhimurium incubated at 37 C or from cells of S. pullorum incubated at 25 C. Cells cultured at 37 C continued to accumulate sulfite when the incubation temperature was shifted to 25 C; cells cultured at 25 C and shifted to 37 C accumulated no sulfite, whereas these cells shifted to 41 C accumulated sulfite. It was concluded that the configuration of the sulfite reductase of S. pullorum strain 6–18 is a function of the incubation temperature at which synthesis occurs. PMID:5122801

  1. Specifically targeted modification of human aldose reductase by physiological disulfides.

    PubMed

    Cappiello, M; Voltarelli, M; Cecconi, I; Vilardo, P G; Dal Monte, M; Marini, I; Del Corso, A; Wilson, D K; Quiocho, F A; Petrash, J M; Mura, U

    1996-12-27

    Aldose reductase is inactivated by physiological disulfides such as GSSG and cystine. To study the mechanism of disulfide-induced enzyme inactivation, we examined the rate and extent of enzyme inactivation using wild-type human aldose reductase and mutants containing cysteine-to-serine substitutions at positions 80 (C80S), 298 (C298S), and 303 (C303S). The wild-type, C80S, and C303S enzymes lost >80% activity following incubation with GSSG, whereas the C298S mutant was not affected. Loss of activity correlated with enzyme thiolation. The binary enzyme-NADP+ complex was less susceptible to enzyme thiolation than the apoenzyme. These results suggest that thiolation of human aldose reductase occurs predominantly at Cys-298. Energy minimization of a hypothetical enzyme complex modified by glutathione at Cys-298 revealed that the glycyl carboxylate of glutathione may participate in a charged interaction with His-110 in a manner strikingly similar to that involving the carboxylate group of the potent aldose reductase inhibitor Zopolrestat. In contrast to what was observed with GSSG and cystine, cystamine inactivated the wild-type enzyme as well as all three cysteine mutants. This suggests that cystamine-induced inactivation of aldose reductase does not involve modification of cysteines exclusively at position 80, 298, or 303. PMID:8969219

  2. Human cytochrome b5 reductase: structure, function, and potential applications.

    PubMed

    Elahian, Fatemeh; Sepehrizadeh, Zargham; Moghimi, Bahareh; Mirzaei, Seyed Abbas

    2014-06-01

    Cytochrome b5 reductase is a flavoprotein that is produced as two different isoforms that have different localizations. The amphipathic microsomal isoform, found in all cell types with the exception of erythrocytes, consists of one hydrophobic membrane-anchoring domain and a larger hydrophilic flavin catalytic domain. The soluble cytochrome b5 reductase isoform, found in human erythrocytes, is a truncated protein that is encoded by an alternative transcript and consists of the larger domain only. Cytochrome b5 reductase is involved in the transfer of reducing equivalents from the physiological electron donor, NADH, via an FAD domain to the small molecules of cytochrome b5. This protein has received much attention from researchers due to its involvement in many oxidation and reduction reactions, such as the reduction of methemoglobin to hemoglobin. Autosomal cytochrome b5 reductase gene deficiency manifests with the accumulation of oxidized Fe+3 and recessive congenital methemoglobinemia in humans. In this article, we provide a comprehensive overview of the structure and function of cytochrome b5 reductase from different eukaryotic sources and its potential use in the food industry, biosensor, and diagnostic areas. PMID:23113554

  3. Are effects of MTHFR (C677T) genotype on BMD confined to women with low folate and riboflavin intake? Analysis of food records from the Danish osteoporosis prevention study

    Microsoft Academic Search

    Bo Abrahamsen; Jonna Skov Madsen; Charlotte Landbo Tofteng; Lis Stilgren; Else Marie Bladbjerg; Søren Risom Kristensen; Kim Brixen; Leif Mosekilde

    2005-01-01

    We have previously found BMD and fracture risk to be significantly associated with the MTHFR (C677T) polymorphism in healthy postmenopausal women in the first years after menopause. Since then, other cohort studies have suggested that sufficient intake of riboflavin and\\/or folate may have the potential to prevent development of low BMD in women with the TT genotype. This could to

  4. Congenital Prothrombotic Disorders in Children with Peripheral Venous and Arterial Thromboses

    Microsoft Academic Search

    Manuela Albisetti; Alexander Moeller; Katharina Waldvogel; Vera Bernet-Buettiker; Vincenzo Cannizzaro; Alexia Anagnostopoulos; Christian Balmer; Markus Schmugge

    2007-01-01

    Aims: To evaluate the prevalence of congenital prothrombotic disorders in children with peripheral venous and arterial thromboses. Methods: Deficiencies in antithrombin (AT), proteins C (PC) and S (PS), and increased lipoprotein (a), and the presence of factor V (FV) G1691A, prothrombin G20210A and methylenetetrahydrofolate reductase (MTHFR) mutations were investigated. Results: Forty-eight patients (mean age, 3.4 years) were investigated. Of these

  5. 3D Beta-coefficient maps displayed over the mean template show areas where brain volume deficits relative to the MDT of up to 0.75% deficit per T allele in the C677T SNP (pink, FDR critical P-value 0.0033) and Homocysteine (blue, FDR critical P-value

    E-print Network

    Thompson, Paul

    of a common single nucleotide polymorphism (SNP) C677T in the MTHFR (methylenetetrahydrofolate reductase) gene discovered that the MTHFR variant, possibly mediating its effects through Hcy, influences volume deficits

  6. Polymorphisms in the thymidylate synthase and serine hydroxymethyltransferase genes and risk of adult acute lymphocytic leukemia

    E-print Network

    California at Berkeley, University of

    (MTHFR) gene at positions C677T and A1298C were associated with lower risk of adult acute lymphocytic,10- methylenetetrahydrofolate reductase (MTHFR), and a decreased risk of adult acute lymphocytic leukemia (ALL).1 Similar

  7. The inhibitory activity of aldose reductase in vitro by constituents of Garcinia mangostana Linn.

    PubMed

    Fatmawati, Sri; Ersam, Taslim; Shimizu, Kuniyoshi

    2015-01-15

    We investigated aldose reductase inhibition of Garcinia mangostana Linn. from Indonesia. Dichloromethane extract of the root bark of this tree was found to demonstrate an IC50 value of 11.98 µg/ml for human aldose reductase in vitro. From the dichloromethane fraction, prenylated xanthones were isolated as potent human aldose reductase inhibitors. We discovered 3-isomangostin to be most potent against aldose reductase, with an IC50 of 3.48 µM. PMID:25636870

  8. Enzymatic Reduction of Alloxan by Thioredoxin and NADPH-Thioredoxin Reductase

    Microsoft Academic Search

    Arne Holmgren; Catharina Lyckeborg

    1980-01-01

    Alloxan reacts with certain sulfhydryl groups either by chemical modification or reduction to dialuric acid. The effects of the drug on NADPH-thioredoxin reductase [thioredoxin reductase (NADPH); NADPH:oxidized-thioredoxin oxidoreductase, EC 1.6.4.5] and thioredoxin-(SH)2, a ubiquitous thiol-dependent disulfide reductase system, are described. Alloxan was a direct substrate for a nearly homogeneous preparation of calf thymus NADPH-thioredoxin reductase with an apparent Km of

  9. UV signature mutations.

    PubMed

    Brash, Douglas E

    2015-01-01

    Sequencing complete tumor genomes and exomes has sparked the cancer field's interest in mutation signatures for identifying the tumor's carcinogen. This review and meta-analysis discusses signatures and their proper use. We first distinguish between a mutagen's canonical mutations—deviations from a random distribution of base changes to create a pattern typical of that mutagen—and the subset of signature mutations, which are unique to that mutagen and permit inference backward from mutations to mutagen. To verify UV signature mutations, we assembled literature datasets on cells exposed to UVC, UVB, UVA, or solar simulator light (SSL) and tested canonical UV mutation features as criteria for clustering datasets. A confirmed UV signature was: ?60% of mutations are C?T at a dipyrimidine site, with ?5% CC?TT. Other canonical features such as a bias for mutations on the nontranscribed strand or at the 3' pyrimidine had limited application. The most robust classifier combined these features with criteria for the rarity of non-UV canonical mutations. In addition, several signatures proposed for specific UV wavelengths were limited to specific genes or species; UV's nonsignature mutations may cause melanoma BRAF mutations; and the mutagen for sunlight-related skin neoplasms may vary between continents. PMID:25354245

  10. 4-Hydroxy-2-oxoglutarate Aldolase Inactivity in Primary Hyperoxaluria Type 3 and Glyoxylate Reductase Inhibition

    PubMed Central

    Riedel, Travis J.; Knight, John; Murray, Michael S.; Milliner, Dawn S.; Holmes, Ross P.; Lowther, W. Todd

    2012-01-01

    Mutations in the gene encoding for 4-hydroxy-2-oxoglutarate aldolase (HOGA) are associated with an excessive production of oxalate in Primary Hyperoxaluria type 3 (PH3). This enzyme is the final step of the hydroxyproline degradation pathway within the mitochondria and catalyzes the cleavage of 4-hydroxy-2-oxoglutarate (HOG) to pyruvate and glyoxylate. No analyses have been performed to assess the consequences of the mutations identified, particularly for those variants that produce either full-length or nearly full-length proteins. In this study, the expression, stability, and activity of nine PH3 human HOGA variants were examined. Using recombinant protein produced in Escherichia coli as well as transfected Chinese hamster ovary (CHO) cells, it was found that all nine PH3 variants are quite unstable, have a tendency to aggregate, and retain no measurable activity. A buildup of HOG was confirmed in the urine, sera and liver samples from PH3 patients. To determine how HOG is cleaved in the absence of HOGA activity, the ability of N-acetylneuraminate aldolase (NAL) to cleave HOG was evaluated. NAL showed minimal activity towards HOG. Whether the expected buildup of HOG in mitochondria could inhibit glyoxylate reductase (GR), the enzyme mutated in PH2, was also evaluated. GR was inhibited by HOG but not by 2-hydroxyglutarate or 2-oxoglutarate. Thus, one hypothetical component of the molecular basis for the excessive oxalate production in PH3 appears to be the inhibition of GR by HOG, resulting in a phenotype similar to PH2. PMID:22771891

  11. Malarial dihydrofolate reductase as a paradigm for drug development against a resistance-compromised target

    PubMed Central

    Yuthavong, Yongyuth; Tarnchompoo, Bongkoch; Vilaivan, Tirayut; Chitnumsub, Penchit; Kamchonwongpaisan, Sumalee; Charman, Susan A.; McLennan, Danielle N.; White, Karen L.; Vivas, Livia; Bongard, Emily; Thongphanchang, Chawanee; Taweechai, Supannee; Vanichtanankul, Jarunee; Rattanajak, Roonglawan; Arwon, Uthai; Fantauzzi, Pascal; Yuvaniyama, Jirundon; Charman, William N.; Matthews, David

    2012-01-01

    Malarial dihydrofolate reductase (DHFR) is the target of antifolate antimalarial drugs such as pyrimethamine and cycloguanil, the clinical efficacy of which have been compromised by resistance arising through mutations at various sites on the enzyme. Here, we describe the use of cocrystal structures with inhibitors and substrates, along with efficacy and pharmacokinetic profiling for the design, characterization, and preclinical development of a selective, highly efficacious, and orally available antimalarial drug candidate that potently inhibits both wild-type and clinically relevant mutated forms of Plasmodium falciparum (Pf) DHFR. Important structural characteristics of P218 include pyrimidine side-chain flexibility and a carboxylate group that makes charge-mediated hydrogen bonds with conserved Arg122 (PfDHFR-TS amino acid numbering). An analogous interaction of P218 with human DHFR is disfavored because of three species-dependent amino acid substitutions in the vicinity of the conserved Arg. Thus, P218 binds to the active site of PfDHFR in a substantially different fashion from the human enzyme, which is the basis for its high selectivity. Unlike pyrimethamine, P218 binds both wild-type and mutant PfDHFR in a slow-on/slow-off tight-binding mode, which prolongs the target residence time. P218, when bound to PfDHFR-TS, resides almost entirely within the envelope mapped out by the dihydrofolate substrate, which may make it less susceptible to resistance mutations. The high in vivo efficacy in a SCID mouse model of P. falciparum malaria, good oral bioavailability, favorable enzyme selectivity, and good safety characteristics of P218 make it a potential candidate for further development. PMID:23035243

  12. Identification and selective inhibition of an isozyme of steroid 5 alpha-reductase in human scalp.

    PubMed

    Harris, G; Azzolina, B; Baginsky, W; Cimis, G; Rasmusson, G H; Tolman, R L; Raetz, C R; Ellsworth, K

    1992-11-15

    Steroid 5 alpha-reductase (EC 1.3.1.22) catalyzes the reduction of testosterone to dihydrotestosterone. The 5 alpha-reductase found in human scalp has been compared with the enzyme found in prostate. The scalp reductase has a broad pH optimum centered at pH 7.0. This is distinctly different from the pH optimum of 5.5 observed with the prostatic form of the enzyme. These enzymes also differ in the Km for testosterone, which is 25-fold higher for the scalp reductase. The most significant difference between the two enzymes is their affinity for inhibitors. Two 4-azasteroids and a 3-carboxyandrostadiene are potent inhibitors of the prostatic reductase but are weak inhibitors of the scalp reductase. In contrast, several N-4-methylazasteroids are good inhibitors of the scalp reductase. These findings support a proposal that different isozymes of 5 alpha-reductase may exist in scalp and prostate. The scalp reductase was also compared to 5 alpha-reductase 1, one of the two enzymes recently cloned from human prostate [Andersson, S. & Russell, D. W. (1990) Proc. Natl. Acad. Sci. USA 87, 3640-3644; and Andersson, S., Berman, D. M., Jenkins, E. P. & Russell, D. W. (1991) Nature (London) 354, 159-161]. The characteristics of the cloned reductase 1 are comparable to those of the scalp reductase. PMID:1438277

  13. Identification and selective inhibition of an isozyme of steroid 5 alpha-reductase in human scalp.

    PubMed Central

    Harris, G; Azzolina, B; Baginsky, W; Cimis, G; Rasmusson, G H; Tolman, R L; Raetz, C R; Ellsworth, K

    1992-01-01

    Steroid 5 alpha-reductase (EC 1.3.1.22) catalyzes the reduction of testosterone to dihydrotestosterone. The 5 alpha-reductase found in human scalp has been compared with the enzyme found in prostate. The scalp reductase has a broad pH optimum centered at pH 7.0. This is distinctly different from the pH optimum of 5.5 observed with the prostatic form of the enzyme. These enzymes also differ in the Km for testosterone, which is 25-fold higher for the scalp reductase. The most significant difference between the two enzymes is their affinity for inhibitors. Two 4-azasteroids and a 3-carboxyandrostadiene are potent inhibitors of the prostatic reductase but are weak inhibitors of the scalp reductase. In contrast, several N-4-methylazasteroids are good inhibitors of the scalp reductase. These findings support a proposal that different isozymes of 5 alpha-reductase may exist in scalp and prostate. The scalp reductase was also compared to 5 alpha-reductase 1, one of the two enzymes recently cloned from human prostate [Andersson, S. & Russell, D. W. (1990) Proc. Natl. Acad. Sci. USA 87, 3640-3644; and Andersson, S., Berman, D. M., Jenkins, E. P. & Russell, D. W. (1991) Nature (London) 354, 159-161]. The characteristics of the cloned reductase 1 are comparable to those of the scalp reductase. PMID:1438277

  14. Effect of cinnamate on nitrate reductase activity in isolated cucumber cotyledons

    Microsoft Academic Search

    P. K. Singh; K. K. Koul; S. B. Tiwari; R. K. Kaul

    1997-01-01

    The effect of cinnamic acid on in vivo nitrate reductase activity and protein content in cucumber cotyledons was studied. Cinnamate increased in vivo nitrate reductase activity and also the total protein content at lower concentrations (0.01–0.1 mM). Higher concentration, however, proved inhibitory. The effect of cinnamate on nitrate reductase activity has been discussed.

  15. Dehydroascorbate and dehydroascorbate reductase are phantom indicators of oxidative stress in plants

    Microsoft Academic Search

    Susanne Morell; Hartmut Follmann; Mario De Tullio; Ingo Häberlein

    1997-01-01

    In many physiological studies dehydroascorbate (DHA) reductase is regarded as one of the chloroplast enzymes involved in the protection against oxidative stress. Here, evidence is presented that plant cells do not possess a specific DHA reductase. The DHA reductase activities measured in plant extracts are due to side reactions of proteins containing redox-active dicysteine sites. Native gel electrophoresis combined with

  16. Amino Acids (2002) 22: 297308 Peptoid inhibition of trypanothione reductase as a potential

    E-print Network

    Schnaufer, Achim

    2002-01-01

    Amino Acids (2002) 22: 297­308 Peptoid inhibition of trypanothione reductase as a potential of the parasite- specific enzyme trypanothione reductase. A lead inhibitor based on a peptoid structure was designed in the present study based on the known strong competitive inhibition of trypanothione reductase

  17. Eur. J. Biochem. 230,460-468 (1995) Trypanothione reductase from Leishmania donovani

    E-print Network

    Schnaufer, Achim

    1995-01-01

    other trypanothione reductases, the leishmania enzyme is unable to use glutathione disulfideEur. J. Biochem. 230,460-468 (1995) 0FEBS 1995 Trypanothione reductase from Leishmania donovani Medicine, England (Received 27 February 1995) - EJB 95 0127/4 Trypanothione reductase was purified

  18. Two Interacting Binding Sites for Quinacrine Derivatives in the Active Site of Trypanothione Reductase

    E-print Network

    Schnaufer, Achim

    to T[SH]2 by trypanothione reductase (TryR), an NADPH-dependent disulfide oxidoreduc- tase. Try Reductase A TEMPLATE FOR DRUG DESIGN* Received for publication, March 22, 2004 Published, JBC Papers DD1 5EH, United Kingdom Trypanothione reductase is a key enzyme in the trypanothione-based redox

  19. Removal of Substrate Inhibition and Increase in Maximal Velocity in the Short Chain Dehydrogenase/Reductase Salutaridine Reductase Involved in Morphine Biosynthesis*

    PubMed Central

    Ziegler, Jörg; Brandt, Wolfgang; Geißler, René; Facchini, Peter J.

    2009-01-01

    Salutaridine reductase (SalR, EC 1.1.1.248) catalyzes the stereospecific reduction of salutaridine to 7(S)-salutaridinol in the biosynthesis of morphine. It belongs to a new, plant-specific class of short-chain dehydrogenases, which are characterized by their monomeric nature and increased length compared with related enzymes. Homology modeling and substrate docking suggested that additional amino acids form a novel ?-helical element, which is involved in substrate binding. Site-directed mutagenesis and subsequent studies on enzyme kinetics revealed the importance of three residues in this element for substrate binding. Further replacement of eight additional residues led to the characterization of the entire substrate binding pocket. In addition, a specific role in salutaridine binding by either hydrogen bond formation or hydrophobic interactions was assigned to each amino acid. Substrate docking also revealed an alternative mode for salutaridine binding, which could explain the strong substrate inhibition of SalR. An alternate arrangement of salutaridine in the enzyme was corroborated by the effect of various amino acid substitutions on substrate inhibition. In most cases, the complete removal of substrate inhibition was accompanied by a substantial loss in enzyme activity. However, some mutations greatly reduced substrate inhibition while maintaining or even increasing the maximal velocity. Based on these results, a double mutant of SalR was created that exhibited the complete absence of substrate inhibition and higher activity compared with wild-type SalR. PMID:19648114

  20. Association of Methylene Tetrahydrofolate Reductase Polymorphism with BMD and Homocysteine in Premenopausal North Indian Women

    PubMed Central

    Pandey, Sanjeev Kumar; Singh, Ankur; Polipalli, Sunil Kumar; Gupta, Sangeeta; Kapoor, Seema

    2013-01-01

    Background and Aim: Osteoporosis (OP) is a common nutrigenomic disease associated with various genetic components. Observational studies have indicated that mildly elevated homocysteine was a strong risk factor for osteoporotic fractures. Yet there is no clear biologic mechanism for an effect of homocysteine on bone.The aim of this study was to investigate the association of MTHFR C677T and A1298C polymorphisms, and to verify the association of these polymorphisms with bone mineral density and homocysteine in premenopausal women of northern India. Material and Methods: We included 402 north Indian patients with altered BMD, both Osteopenic (OPN) and Osteoporosis, and normal controls. Genotype identification for MTHFR C677T and A1298C polymorphisms were analyzed by PCR-RFLP method, correlated with Bone Mineral Density (BMD), Homocysteine (Hcy), Folate and Vitamin B12. Results: The study groups did not differ in terms of age, weight and body mass indices. Prevalence of Genotype frequencies (GFs) for MTHFRC677T OP were (n: 402): CC 361 (89.8%), CT 25 (6.22%), TT 16 (3.98%) and that for MTHFR A1298C were (n: 402) AA 353(87.81%), AC 29(7.21%), CC 20(4.98%). Folate was significantly lower in the OP group than those in both the other groups, while there was no significant difference in Hcy in the OP group relative to OPN, as compared to controls. Conclusion: The GFs for MTHFR C677T and A1298C polymorphisms were not different between both groups. In conclusion, polymorphism of the MTHFR 677T is associated with small differences in BMD with folate levels. Further, more investigations should be done in larger studies for other epigenetic pathways, that may increase the risk of Osteoporosis. PMID:24551672

  1. A Child With Diamond-Blackfan Anemia, Methylenetetrahydrofolate Reductase Mutation, and Perinatal Stroke

    Microsoft Academic Search

    Matthew W. Butrum; Linda S. Williams; Meredith R. Golomb

    2003-01-01

    Diamond-Blackfan anemia is a congenital hypoproliferative anemia known to be associated with diverse physical anomalies affecting the thumb, craniofacial bones, urogenital system, and heart; prematurity; and fetal demise. We report the case of a 16-month-old boy with Diamond-Blackfan anemia noted to have decreased use of his right side since birth. Magnetic resonance imaging demonstrated a large area of encephalomalacia in

  2. Plant methionine sulfoxide reductase A and B multigenic families

    Microsoft Academic Search

    Nicolas Rouhier; Christina Vieira Dos Santos; Lionel Tarrago; Pascal Rey

    2006-01-01

    Methionine oxidation to methionine sulfoxide (MetSo), which results in modification of activity and conformation for many proteins, is reversed by an enzyme present in most organisms and termed as methionine sulfoxide reductase (MSR). On the basis of substrate stereospecificity, two types of MSR, A and B, that do not share any sequence similarity, have been identified. In the present review,

  3. A Detoxifying Oxygen Reductase in the Anaerobic Protozoan Entamoeba histolytica

    PubMed Central

    Vicente, João B.; Tran, Vy; Pinto, Liliana; Teixeira, Miguel

    2012-01-01

    We report the characterization of a bacterial-type oxygen reductase abundant in the cytoplasm of the anaerobic protozoan parasite Entamoeba histolytica. Upon host infection, E. histolytica is confronted with various oxygen tensions in the host intestine, as well as increased reactive oxygen and nitrogen species at the site of local tissue inflammation. Resistance to oxygen-derived stress thus plays an important role in the pathogenic potential of E. histolytica. The genome of E. histolytica has four genes that encode flavodiiron proteins, which are bacterial-type oxygen or nitric oxide reductases and were likely acquired by lateral gene transfer from prokaryotes. The EhFdp1 gene has higher expression in virulent than in nonvirulent Entamoeba strains and species, hinting that the response to oxidative stress may be one correlate of virulence potential. We demonstrate that EhFdp1 is abundantly expressed in the cytoplasm of E. histolytica and that the protein levels are markedly increased (up to ?5-fold) upon oxygen exposure. Additionally, we produced fully functional recombinant EhFdp1 and demonstrated that this enzyme is a specific and robust oxygen reductase but has poor nitric oxide reductase activity. This observation represents a new mechanism of oxygen resistance in the anaerobic protozoan pathogen E. histolytica. PMID:22798391

  4. IDENTIFICATION OF DISULPHIDE REDUCTASES IN CAMPYLOBACTERALES: A BIOINFORMATICS INVESTIGATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Disulphide reductases of host-colonising bacteria are involved in the expression of virulence factors, resistance to drugs, and elimination of compounds toxic to the microorganisms. The four species Campylobacter jejuni, Helicobacter pylori, Wolinella succinogenes and Arcobacter butzleri of the orde...

  5. Thioredoxin and NADP-thioredoxin reductase from cultured carrot cells

    NASA Technical Reports Server (NTRS)

    Johnson, T. C.; Cao, R. Q.; Kung, J. E.; Buchanan, B. B.

    1987-01-01

    Dark-grown carrot (Daucus carota L.) tissue cultures were found to contain both protein components of the NADP/thioredoxin system--NADP-thioredoxin reductase and the thioredoxin characteristic of heterotrophic systems, thioredoxin h. Thioredoxin h was purified to apparent homogeneity and, like typical bacterial counterparts, was a 12-kdalton (kDa) acidic protein capable of activating chloroplast NADP-malate dehydrogenase (EC 1.1.1.82) more effectively than fructose-1,6-bisphosphatase (EC 3.1.3.11). NADP-thioredoxin reductase (EC 1.6.4.5) was partially purified and found to be an arsenite-sensitive enzyme composed of two 34-kDa subunits. Carrot NADP-thioredoxin reductase resembled more closely its counterpart from bacteria rather than animal cells in acceptor (thioredoxin) specificity. Upon greening of the cells, the content of NADP-thioredoxin-reductase activity, and, to a lesser extent, thioredoxin h decreased. The results confirm the presence of a heterotrophic-type thioredoxin system in plant cells and raise the question of its physiological function.

  6. Mutator Mutations Enhance Tumorigenic Efficiency across Fitness Landscapes

    PubMed Central

    Beckman, Robert A.

    2009-01-01

    Background Tumorigenesis requires multiple genetic changes. Mutator mutations are mutations that increase genomic instability, and according to the mutator hypothesis, accelerate tumorigenesis by facilitating oncogenic mutations. Alternatively, repeated lineage selection and expansion without increased mutation frequency may explain observed cancer incidence. Mutator lineages also risk increased deleterious mutations, leading to extinction, thus providing another counterargument to the mutator hypothesis. Both selection and extinction involve changes in lineage fitness, which may be represented as “trajectories” through a “fitness landscape” defined by genetics and environment. Methodology/Principal Findings Here I systematically analyze the relative efficiency of tumorigenesis with and without mutator mutations by evaluating archetypal fitness trajectories using deterministic and stochastic mathematical models. I hypothesize that tumorigenic mechanisms occur clinically in proportion to their relative efficiency. This work quantifies the relative importance of mutator pathways as a function of experimentally measurable parameters, demonstrating that mutator pathways generally enhance efficiency of tumorigenesis. An optimal mutation rate for tumor evolution is derived, and shown to differ from that for species evolution. Conclusions/Significance The models address the major counterarguments to the mutator hypothesis, confirming that mutator mechanisms are generally more efficient routes to tumorigenesis than non-mutator mechanisms. Mutator mutations are more likely to occur early, and to occur when more oncogenic mutations are required to create a tumor. Mutator mutations likely occur in a minority of premalignant lesions, but these mutator premalignant lesions are disproportionately likely to develop into malignant tumors. Tumor heterogeneity due to mutator mutations may contribute to therapeutic resistance, and the degree of heterogeneity of tumors may need to be considered when therapeutic strategies are devised. The model explains and predicts important biological observations in bacterial and mouse systems, as well as clinical observations. PMID:19517009

  7. Quantification of random genomic mutations

    Microsoft Academic Search

    Jason H Bielas; Lawrence A Loeb

    2005-01-01

    Cancer cells contain numerous clonal mutations. It has been theorized that malignant cells sustain an elevated mutation rate and, as a consequence, harbor yet larger numbers of random point mutations. Testing this hypothesis has been precluded by lack of an assay to measure random mutations—that is, mutations that occur in only one or a few cells of a population. We

  8. 5,6-Dihydro-5-aza-2’-deoxycytidine potentiates the anti-HIV-1 activity of ribonucleotide reductase inhibitors

    PubMed Central

    Rawson, Jonathan M.; Heineman, Richard H.; Beach, Lauren B.; Martin, Jessica L.; Schnettler, Erica K.; Dapp, Michael J.; Patterson, Steven E.; Mansky, Louis M.

    2014-01-01

    The nucleoside analog 5,6-dihydro-5-aza-2’-deoxycytidine (KP-1212) has been investigated as a first-in-class lethal mutagen of human immunodeficiency virus type-1 (HIV-1). Since a prodrug monotherapy did not reduce viral loads in Phase II clinical trials, we tested if ribonucleotide reductase inhibitors (RNRIs) combined with KP-1212 would improve antiviral activity. KP-1212 potentiated the activity of gemcitabine and resveratrol and simultaneously increased the viral mutant frequency. G-to-C mutations predominated with the KP-1212-resveratrol combination. These observations represent the first demonstration of a mild anti-HIV-1 mutagen potentiating the antiretroviral activity of RNRIs and encourage the clinical translation of enhanced viral mutagenesis in treating HIV-1 infection. PMID:24120088

  9. Aldo-keto reductases as modulators of stress response.

    PubMed

    Chang, Qing; Harter, Theresa M; Rikimaru, Loryn T; Petrash, J Mark

    2003-02-01

    Human aldose reductase (AKR1B1) has been implicated as a factor in the pathogenesis of diabetic complications. However, little is known about the physiological role of this enzyme or of related aldo-keto reductases in human tissues. In mammalian systems, a gene knock out approach is often employed as an experimental strategy to probe for gene function. However, in the murine system, phenotypic characterization of an aldose reductase (AKR1B3) knock out is likely to be complicated due to functional compensation by redundant AKRs including AKRs 1A (aldehyde reductase), 1B7 (FR-1) and 1B8 (MVDP). As an alternate strategy, we are examining the budding yeast Saccharomyces cerevisiae as a model system for a functional genomics study of AKRs. A distinct advantage of this system centers on the ability to readily ablate multiple targeted genes in a single strain. In addition to providing insights into functional redundancy, this system allows us to use a genetic approach to study possible effector pathways associated with one or more individual genes. Yeast open reading frames (ORFs) encoding AKRs with functional similarity to human aldose reductase (AKR1B1) were identified by BLAST analysis and were functionally validated by studies of recombinant proteins. By ablating three of the yeast AKR genes most functionally similar to AKR1B1, we have created a unique strain of S. cerevisiae that shows enhanced sensitivity to stress. Ongoing studies with oligonucleotide arrays show that the triple null strain has an altered transcription profile consistent with an enhanced stress response in comparison with the parental strain. These data indicate that AKR-null strains may provide new insights into signaling mechanisms involving this family of proteins. PMID:12604219

  10. Effect modification by population dietary folate on the association between MTHFR genotype, homocysteine, and stroke risk: a meta-analysis of genetic studies and randomised trials

    PubMed Central

    Holmes, Michael V; Newcombe, Paul; Hubacek, Jaroslav A; Sofat, Reecha; Ricketts, Sally L; Cooper, Jackie; Breteler, Monique MB; Bautista, Leonelo E; Sharma, Pankaj; Whittaker, John C; Smeeth, Liam; Fowkes, F Gerald R; Algra, Ale; Shmeleva, Veronika; Szolnoki, Zoltan; Roest, Mark; Linnebank, Michael; Zacho, Jeppe; Nalls, Michael A; Singleton, Andrew B; Ferrucci, Luigi; Hardy, John; Worrall, Bradford B; Rich, Stephen S; Matarin, Mar; Norman, Paul E; Flicker, Leon; Almeida, Osvaldo P; van Bockxmeer, Frank M; Shimokata, Hiroshi; Khaw, Kay-Tee; Wareham, Nicholas J; Bobak, Martin; Sterne, Jonathan AC; Smith, George Davey; Talmud, Philippa J; van Duijn, Cornelia; Humphries, Steve E; Price, Jackie F; Ebrahim, Shah; Lawlor, Debbie A; Hankey, Graeme J; Meschia, James F; Sandhu, Manjinder S; Hingorani, Aroon D; Casas, Juan P

    2011-01-01

    Summary Background The MTHFR 677C?T polymorphism has been associated with raised homocysteine concentration and increased risk of stroke. A previous overview showed that the effects were greatest in regions with low dietary folate consumption, but differentiation between the effect of folate and small-study bias was difficult. A meta-analysis of randomised trials of homocysteine-lowering interventions showed no reduction in coronary heart disease events or stroke, but the trials were generally set in populations with high folate consumption. We aimed to reduce the effect of small-study bias and investigate whether folate status modifies the association between MTHFR 677C?T and stroke in a genetic analysis and meta-analysis of randomised controlled trials. Methods We established a collaboration of genetic studies consisting of 237 datasets including 59?995 individuals with data for homocysteine and 20?885 stroke events. We compared the genetic findings with a meta-analysis of 13 randomised trials of homocysteine-lowering treatments and stroke risk (45?549 individuals, 2314 stroke events, 269 transient ischaemic attacks). Findings The effect of the MTHFR 677C?T variant on homocysteine concentration was larger in low folate regions (Asia; difference between individuals with TT versus CC genotype, 3·12 ?mol/L, 95% CI 2·23 to 4·01) than in areas with folate fortification (America, Australia, and New Zealand, high; 0·13 ?mol/L, ?0·85 to 1·11). The odds ratio (OR) for stroke was also higher in Asia (1·68, 95% CI 1·44 to 1·97) than in America, Australia, and New Zealand, high (1·03, 0·84 to 1·25). Most randomised trials took place in regions with high or increasing population folate concentrations. The summary relative risk (RR) of stroke in trials of homocysteine-lowering interventions (0·94, 95% CI 0·85 to 1·04) was similar to that predicted for the same extent of homocysteine reduction in large genetic studies in populations with similar folate status (predicted RR 1·00, 95% CI 0·90 to 1·11). Although the predicted effect of homocysteine reduction from large genetic studies in low folate regions (Asia) was larger (RR 0·78, 95% CI 0·68 to 0·90), no trial has evaluated the effect of lowering of homocysteine on stroke risk exclusively in a low folate region. Interpretation In regions with increasing levels or established policies of population folate supplementation, evidence from genetic studies and randomised trials is concordant in suggesting an absence of benefit from lowering of homocysteine for prevention of stroke. Further large-scale genetic studies of the association between MTHFR 677C?T and stroke in low folate settings are needed to distinguish effect modification by folate from small-study bias. If future randomised trials of homocysteine-lowering interventions for stroke prevention are undertaken, they should take place in regions with low folate consumption. Funding Full funding sources listed at end of paper (see Acknowledgments). PMID:21803414

  11. A Lower Degree of PBMC L1 Methylation in Women with Lower Folate Status May Explain the MTHFR C677T Polymorphism Associated Higher Risk of CIN in the US Post Folic Acid Fortification Era

    PubMed Central

    Badiga, Suguna; Johanning, Gary L.; Macaluso, Maurizio; Azuero, Andres; Chambers, Michelle M.; Siddiqui, Nuzhat R.; Piyathilake, Chandrika J.

    2014-01-01

    Background Studies in populations unexposed to folic acid (FA) fortification have demonstrated that MTHFR C677T polymorphism is associated with increased risk of higher grades of cervical intraepithelial neoplasia (CIN 2+). However, it is unknown whether exposure to higher folate as a result of the FA fortification program has altered the association between MTHFR C677T and risk of CIN, or the mechanisms involved with such alterations. The current study investigated the following in a FA fortified population: 1) The association between MTHFR C677T polymorphism and risk of CIN 2+; 2) The modifying effects of plasma folate concentrations on this association; and 3) The modifying effects of plasma folate on the association between the polymorphism and degree of methylation of long interspersed nucleotide elements (L1s), in peripheral blood mononuclear cell (PBMC) DNA, a documented biomarker of CIN risk. Methods The study included 457 US women diagnosed with either CIN 2+ (cases) or ? CIN 1 (non-cases). Unconditional logistic regression models were used to test the associations after adjusting for relevant risk factors for CIN. Results The 677CT/TT MTHFR genotypes were not associated with the risk of CIN 2+. Women with CT/TT genotype with lower folate, however, were more likely to be diagnosed with CIN 2+ compared to women with CT/TT genotype with higher folate (OR?=?2.41, P?=?0.030). Women with CT/TT genotype with lower folate were less likely to have a higher degree of PBMC L1 methylation compared to women with CT/TT genotype with higher folate (OR?=?0.28, P?=?0.017). Conclusions This study provides the first evidence that the MTHFR 677CT/TT genotype-associated lower degree of PBMC L1 methylation increases the risk of CIN 2+ in women in the US post-FA fortification era. Thus, even in the post-FA fortification era, not all women have adequate folate status to overcome MTHFR 677CT/TT genotype-associated lower degree of L1 methylation. PMID:25302494

  12. Molecular studies in Portuguese patients with Smith–Lemli–Opitz syndrome and report of three new mutations in DHCR7

    Microsoft Academic Search

    M. L. Cardoso; A. Balreira; E. Martins; L. Nunes; A. Cabral; M. Marques; M. Reis Lima; J. S. Marques; A. Medeira; I. Cordeiro; S. Pedro; M. C. Mota; C. Dionisi-Vici; F. M. Santorelli; C. A. J. M. Jakobs; P. T. Clayton; L. Vilarinho

    2005-01-01

    Smith–Lemli–Opitz syndrome (SLO) is an autosomal recessive disorder characterised by craniofacial dysmorphism, mental retardation, multiple congenital anomalies, and increased levels of 7-dehydrocholesterol (7-DHC) in body tissues and fluids. SLO is caused by mutations in the DHCR7 gene which encodes 7-dehydrocholesterol reductase, the last enzyme of cholesterol biosynthesis pathway. In our investigation, we screened 682 dysmorphic\\/mentally retarded Portuguese patients for abnormal

  13. Sequence variation in the dihydrofolate reductase-thymidylate synthase (DHFR-TS) and trypanothione reductase (TR) genes of

    E-print Network

    Machado, Carlos A.

    reductase (TR) genes of Trypanosoma cruzi Carlos A. Machado *, Francisco J. Ayala Department of Ecology coding for those enzymes in a large sample of strains from Trypanosoma cruzi, the agent of Chagas rights reserved. Keywords: DHFR-TS; TR; Trypanosoma cruzi; Polymorphism; Evolution 1. Introduction

  14. Crystal structures of pinoresinol-lariciresinol and phenylcoumaran benzylic ether reductases and their relationship to isoflavone reductases

    NASA Technical Reports Server (NTRS)

    Min, Tongpil; Kasahara, Hiroyuki; Bedgar, Diana L.; Youn, Buhyun; Lawrence, Paulraj K.; Gang, David R.; Halls, Steven C.; Park, HaJeung; Hilsenbeck, Jacqueline L.; Davin, Laurence B.; Lewis, Norman G.; Kang, ChulHee

    2003-01-01

    Despite the importance of plant lignans and isoflavonoids in human health protection (e.g. for both treatment and prevention of onset of various cancers) as well as in plant biology (e.g. in defense functions and in heartwood development), systematic studies on the enzymes involved in their biosynthesis have only recently begun. In this investigation, three NADPH-dependent aromatic alcohol reductases were comprehensively studied, namely pinoresinol-lariciresinol reductase (PLR), phenylcoumaran benzylic ether reductase (PCBER), and isoflavone reductase (IFR), which are involved in central steps to the various important bioactive lignans and isoflavonoids. Of particular interest was in determining how differing regio- and enantiospecificities are achieved with the different enzymes, despite each apparently going through similar enone intermediates. Initially, the three-dimensional x-ray crystal structures of both PLR_Tp1 and PCBER_Pt1 were solved and refined to 2.5 and 2.2 A resolutions, respectively. Not only do they share high gene sequence similarity, but their structures are similar, having a continuous alpha/beta NADPH-binding domain and a smaller substrate-binding domain. IFR (whose crystal structure is not yet obtained) was also compared (modeled) with PLR and PCBER and was deduced to have the same overall basic structure. The basis for the distinct enantio-specific and regio-specific reactions of PCBER, PLR, and IFR, as well as the reaction mechanism and participating residues involved (as identified by site-directed mutagenesis), are discussed.

  15. Xylose reductase from Pichia stipitis with altered coenzyme preference improves ethanolic xylose fermentation by recombinant Saccharomyces cerevisiae

    PubMed Central

    Bengtsson, Oskar; Hahn-Hägerdal, Bärbel; Gorwa-Grauslund, Marie F

    2009-01-01

    Background Xylose reductase (XR) and xylitol dehydrogenase (XDH) from Pichia stipitis are the two enzymes most commonly used in recombinant Saccharomyces cerevisiae strains engineered for xylose utilization. The availability of NAD+ for XDH is limited during anaerobic xylose fermentation because of the preference of XR for NADPH. This in turn results in xylitol formation and reduced ethanol yield. The coenzyme preference of P. stipitis XR was changed by site-directed mutagenesis with the aim to engineer it towards NADH-preference. Results XR variants were evaluated in S. cerevisiae strains with the following genetic modifications: overexpressed native P. stipitis XDH, overexpressed xylulokinase, overexpressed non-oxidative pentose phosphate pathway and deleted GRE3 gene encoding an NADPH dependent aldose reductase. All overexpressed genes were chromosomally integrated to ensure stable expression. Crude extracts of four different strains overexpressing genes encoding native P. stipitis XR, K270M and K270R mutants, as well as Candida parapsilosis XR, were enzymatically characterized. The physiological effects of the mutations were investigated in anaerobic xylose fermentation. The strain overexpressing P. stipitis XR with the K270R mutation gave an ethanol yield of 0.39 g (g consumed sugars)-1, a xylitol yield of 0.05 g (g consumed xylose)-1 and a xylose consumption rate of 0.28 g (g biomass)-1 h-1 in continuous fermentation at a dilution rate of 0.12 h-1, with 10 g l-1 glucose and 10 g l-1 xylose as carbon sources. Conclusion The cofactor preference of P. stipitis XR was altered by site-directed mutagenesis. When the K270R XR was combined with a metabolic engineering strategy that ensures high xylose utilization capabilities, a recombinant S. cerevisiae strain was created that provides a unique combination of high xylose consumption rate, high ethanol yield and low xylitol yield during ethanolic xylose fermentation. PMID:19416504

  16. Mutation Clustering Shamaila Hussain

    E-print Network

    Singer, Jeremy

    Mutation Clustering Shamaila Hussain shamaila.2.hussain@kcl.ac.uk Student Number: 0425528 to reduce the computational cost of the mutation testing, reducing the number of the mutants by clustering. K-means clustering algorithm and agglomerative hierarchical clustering algorithm are implemented

  17. IBMFS - gene mutations

    Cancer.gov

    A "mutation" is a change in a gene that prevents it from working properly. A "germline" mutation is a change that occurs in the egg or the sperm, or both, and is passed from one parent or both parents to the child.

  18. Multiplex detection of mutations.

    PubMed

    Perlin, David S; Balashov, Sergey; Park, Steven

    2008-01-01

    Rapid and reliable detection of mutations at the genetic level is an integral part of modern molecular diagnostics. These mutations can range from dominant single nucleotide polymorphisms within specific loci to codominant heterozygotic insertions and they present considerable challenges to investigators in developing rapid nucleic acid-based amplification assays that can distinguish wild-type from mutant alleles. The recent improvements of real-time polymerase chain reaction (PCR) using self-reporting fluorescence probes have given researchers a powerful tool in developing assays for mutation detection that can be multiplexed for high-throughput screening of multiple mutations and cost effectiveness. Here we describe an application of a multiplexed real-time PCR assay using Molecular Beacon probes for the detection of mutations in codon 54 of the CYP51A gene in Aspergillus fumigatus conferring triazole resistance. PMID:18695956

  19. Mutational Spectrum of Smith-Lemli-Opitz Syndrome Patients in Hungary

    PubMed Central

    Balogh, I.; Koczok, K.; Szabó, G.P.; Török, O.; Hadzsiev, K.; Csábi, G.; Balogh, L.; Dzsudzsák, E.; Ajzner, É.; Szabó, L.; Csákváry, V.; Oláh, A.V.

    2012-01-01

    Smith-Lemli-Opitz (SLO) syndrome is an autosomal recessive disorder characterized by multiple congenital abnormalities and mental retardation. The condition is caused by the deficiency of 7-dehydrocholesterol reductase (DHCR7) which catalyzes the final step in cholesterol biosynthesis. Biochemical diagnosis is based on increased concentration of 7-dehydrocholesterol (7-DHC) in the patient serum. Both life expectancy and quality of life are severely affected by the disease. The estimated prevalence of SLO syndrome ranges between 1:20,000 and 1:40,000 among Caucasians. Although the mutational spectrum of the disease is wide, approximately 10 mutations are responsible for more than 80% of the cases. These mutations show a large interethnic variability. There are no mutation distribution data from Hungary to date. Thirteen patients were diagnosed with SLO syndrome in our laboratory. As first-line tests, serum 7-DHC and total cholesterol were measured and, in positive cases, molecular genetic analysis of the DHCR7 gene was performed. Complete genetic background of the disease could be identified in 12 cases. In 1 case only 1 mutation was detected in a heterozygote form. One patient was homozygous for the common splice site mutation c.964–1G>C, while all other patients were compound heterozygotes. One novel missense mutation, c.374A>G (p.Tyr125Cys) was identified. PMID:23293579

  20. Transcriptional Activation of the Aldehyde Reductase YqhD by YqhC and Its Implication in Glyoxal Metabolism of Escherichia coli K-12?

    PubMed Central

    Lee, Changhan; Kim, Insook; Lee, Junghoon; Lee, Kang-Lok; Min, Bumchan; Park, Chankyu

    2010-01-01

    The reactive ?-oxoaldehydes such as glyoxal (GO) and methylglyoxal (MG) are generated in vivo from sugars through oxidative stress. GO and MG are believed to be removed from cells by glutathione-dependent glyoxalases and other aldehyde reductases. We isolated a number of GO-resistant (GOr) mutants from Escherichia coli strain MG1655 on LB plates containing 10 mM GO. By tagging the mutations with the transposon TnphoA-132 and determining their cotransductional linkages, we were able to identify a locus to which most of the GOr mutations were mapped. DNA sequencing of the locus revealed that it contains the yqhC gene, which is predicted to encode an AraC-type transcriptional regulator of unknown function. The GOr mutations we identified result in missense changes in yqhC and were concentrated in the predicted regulatory domain of the protein, thereby constitutively activating the product of the adjacent gene yqhD. The transcriptional activation of yqhD by wild-type YqhC and its mutant forms was established by an assay with a ?-galactosidase reporter fusion, as well as with real-time quantitative reverse transcription-PCR. We demonstrated that YqhC binds to the promoter region of yqhD and that this binding is abolished by a mutation in the potential target site, which is similar to the consensus sequence of its homolog SoxS. YqhD facilitates the removal of GO through its NADPH-dependent enzymatic reduction activity by converting it to ethadiol via glycolaldehyde, as detected by nuclear magnetic resonance, as well as by spectroscopic measurements. Therefore, we propose that YqhC is a transcriptional activator of YqhD, which acts as an aldehyde reductase with specificity for certain aldehydes, including GO. PMID:20543070

  1. Steroidal antiandrogens and 5alpha-reductase inhibitors.

    PubMed

    Bratoeff, E; Ramírez, E; Murillo, E; Flores, G; Cabeza, M

    1999-12-01

    The purpose of this work is to synthesize a pregnane derivative with a high antiandrogenic effect or a high inhibitory activity for the enzyme 5 alpha-reductase type 2. Benign prostatic hyperplasia and prostate cancer are androgen dependent diseases which afflict a large percentage of the male population. Dihydrotestosterone 3, a 5 alpha-reductase metabolite of testosterone 2 has been implicated as a causative factor in the progression of these diseases, largely through the clinical evaluation of males who are genetically deficient of steroid 5 alpha-reductase enzyme. As a result of this study, the inhibition of this enzyme has become a pharmacological strategy for the design and synthesis of new drugs. The advent of finasteride 22 "figure 5" a 5 alpha-reductase inhibitor, has greatly alleviated the symptoms associated with benign prostatic hyperplasia. On the other hand, the discovery of cyproterone acetate 4 "figure 2" alone or in combination with the antiandrogens flutamide 14 "figure 3" or bicalutamide 21 has greatly reduced the misery of prostate cancer. Prostate cancer kills about 40,000 men in the USA and approximately 400,000 prostatectomies are performed each year. In our laboratory we have recently synthesized ten new progesterone derivatives 17 alpha-acyloyloxy-6-halo (chloro, bromo) 16 beta-methyl-4, 6-pregnadiene-3, 20-diones (54a-54e and 55a-55e), "figure 10". These steroids were evaluated as antiandrogens and exhibited a much higher activity than the commercially available cyproterone acetate 4. The same compounds were also evaluated as 5 alpha-reductase inhibitors and showed a slightly higher inhibitory activity than that of finasteride 22, the drug of choice today for the treatment of benign prostatic hyperplasia In another study we synthesized several new 4-halo (bromo and chloro) 17 alpha-benzoyloxy and also 4-halo-17 alpha-acetoxy progesterone derivatives (58-63) "figure 13". These compounds were prepared from the commercially available 17 alpha-acetoxy progesterone 56. The pharmacological evaluation of these steroids "figure 14" indicated that the 17 alpha-benzoyloxy derivatives (4-chloro and bromo) 62 and 63 were very potent antiandrogens. On the other hand, the 4-halo (bromo and chloro) 17 alpha-acetoxy (58, 59) and the 17 alpha-benzoyloxy-4-chloro analog 63 showed a very high inhibitory activity for the enzyme 5 alpha-reductase type 2 "figure 15". PMID:10519917

  2. Structural insights into the dehydroascorbate reductase activity of human omega-class glutathione transferases.

    PubMed

    Zhou, Huina; Brock, Joseph; Liu, Dan; Board, Philip G; Oakley, Aaron J

    2012-07-13

    The reduction of dehydroascorbate (DHA) to ascorbic acid (AA) is a vital cellular function. The omega-class glutathione transferases (GSTs) catalyze several reductive reactions in cellular biochemistry, including DHA reduction. In humans, two isozymes (GSTO1-1 and GSTO2-2) with significant DHA reductase (DHAR) activity are found, sharing 64% sequence identity. While the activity of GSTO2-2 is higher, it is significantly more unstable in vitro. We report the first crystal structures of human GSTO2-2, stabilized through site-directed mutagenesis and determined at 1.9 Å resolution in the presence and absence of glutathione (GSH). The structure of a human GSTO1-1 has been determined at 1.7 Å resolution in complex with the reaction product AA, which unexpectedly binds in the G-site, where the glutamyl moiety of GSH binds. The structure suggests a similar mode of ascorbate binding in GSTO2-2. This is the first time that a non-GSH-based reaction product has been observed in the G-site of any GST. AA stacks against a conserved aromatic residue, F34 (equivalent to Y34 in GSTO2-2). Mutation of Y34 to alanine in GSTO2-2 eliminates DHAR activity. From these structures and other biochemical data, we propose a mechanism of substrate binding and catalysis of DHAR activity. PMID:22522127

  3. Connecting Protein Conformational Dynamics with Catalytic Function as Illustrated in Dihydrofolate Reductase

    PubMed Central

    Fan, Yao; Cembran, Alessandro; Ma, Shuhua; Gao, Jiali

    2013-01-01

    Combined QM/MM molecular dynamics simulations reveal that the M20 loop conformational dynamics of dihydrofolate reductase (DHFR) is severely restricted at the transition state of the hydride transfer as a result of the M42W/G121V double mutation. Consequently, the double mutant enzyme has a reduced entropy of activation, i.e., increased entropic barrier, and altered temperature dependence of kinetic isotope effects in comparison with wild-type DHFR. Interestingly, both in the wild-type DHFR and the double mutant, the average donor-acceptor distances are essentially the same in the Michaelis complex state (about 3.5 Å) and the transition state (2.7 Å). It was found that an additional hydrogen bond is formed to stabilize the M20 loop in the closed conformation in the M42W/G121V double mutant. The computational results reflect a similar aim designed to knock out precisely the dynamic flexibility of the M20 loop in a different double mutant, N23PP/S148A. PMID:23297871

  4. Connecting protein conformational dynamics with catalytic function as illustrated in dihydrofolate reductase.

    PubMed

    Fan, Yao; Cembran, Alessandro; Ma, Shuhua; Gao, Jiali

    2013-03-26

    Combined quantum mechanics/molecular mechanics molecular dynamics simulations reveal that the M20 loop conformational dynamics of dihydrofolate reductase (DHFR) is severely restricted at the transition state of the hydride transfer as a result of the M42W/G121V double mutation. Consequently, the double-mutant enzyme has a reduced entropy of activation, i.e., increased entropic barrier, and altered temperature dependence of kinetic isotope effects in comparison with those of wild-type DHFR. Interestingly, in both wild-type DHFR and the double mutant, the average donor-acceptor distances are essentially the same in the Michaelis complex state (~3.5 Å) and the transition state (2.7 Å). It was found that an additional hydrogen bond is formed to stabilize the M20 loop in the closed conformation in the M42W/G121V double mutant. The computational results reflect a similar aim designed to knock out precisely the dynamic flexibility of the M20 loop in a different double mutant, N23PP/S148A. PMID:23297871

  5. Superoxide reduction by a superoxide reductase lacking the highly conserved lysine residue

    DOE PAGESBeta

    Teixeira, Miguel [Univ. Nova de Lisboa, Oeiras (Portugal); Cabelli, Diane [Brookhaven National Lab. (BNL), Upton, NY (United States); Pinto, Ana F. [Univ. Nova de Lisboa, Oeiras (Portugal); Karolinska Inst., Stockholm (Sweden); Romao, Celia V. [Univ. Nova de Lisboa, Oeiras (Portugal); Pinto, Liliana C. [Univ. Nova de Lisboa, Oeiras (Portugal); Huber, Harald [Univ. Regensburg, Regensburg (Germany); Saraiva, Ligia M. [Univ. Nova de Lisboa, Oeiras (Portugal); Todorovic, Smilja [Univ. Nova de Lisboa, Oeiras (Portugal)

    2015-01-01

    Superoxide reductases (SORs) are the most recently identified superoxide detoxification systems, being found in microorganisms from the three domains of life. These enzymes are characterized by a catalytic mononuclear iron site, with one cysteine and four histidine ligands of the ferrous active form. A lysine residue in the –EKHVP– motif, located close to the active site, has been considered to be essential for the enzyme function, by contributing to the positive surface patch that attracts the superoxide anion and by controlling the chemistry of the catalytic mechanism through a hydrogen bond network. However, we show here that this residue is substituted by non-equivalent amino acids in several putative SORs from Archaea and unicellular Eukarya. In this work, we focus on mechanistic and spectroscopic studies of one of these less common enzymes, the SOR from the hyperthermophilic crenarchaeon Ignicoccus hospitalis. We employ pulse radiolysis fast kinetics and spectroscopic approaches to study the wild-type enzyme (?E??T??HVP?), and two mutants, T24K and E23A, the later mimicking enzymes lacking both the lysine and glutamate (a ferric ion ligand) of the motif. The efficiency of the wild type protein and mutants in reducing superoxide is comparable to other SORs, revealing the robustness of these enzymes to single mutations.

  6. Binding of 1-benzopyran-4-one derivatives to aldose reductase: a free energy perturbation study.

    PubMed

    Rastelli, Giulio; Costantino, Luca; Gamberini, M Cristina; Del Corso, Antonella; Mura, Umberto; Petrash, J Mark; Ferrari, Anna Maria; Pacchioni, Sara

    2002-05-01

    The relative binding affinities to human aldose reductase (ALR2) of three new 7-hydroxy-2-benzyl-4H-1-benzopyran-4-one inhibitors were predicted by free energy perturbation (FEP) simulations. Molecular substitutions were specifically designed to investigate the role of hydrogen bonding at the active site of ALR2. Starting from the lead inhibitor 7-hydroxy-2-(4'-hydroxybenzyl)-4H-1-benzopyran-4-one, the 4'-hydroxyl was mutated to methyl and to trifluoromethyl, and an hydroxyl at position 8 was additionally introduced. Once synthesized and tested as inhibitors of ALR2, the compounds displayed variations of K(i) that were in qualitative to quantitative agreement with the calculated relative free energies of binding. The results, discussed in terms of balance between free energies of solvation and free energies of binding to ALR2, elucidate the importance of hydrogen bonding with Thr113 and with Trp111 and cofactor, and provide a rationale to the observed differences in binding affinities. PMID:11886805

  7. Superoxide reduction by a superoxide reductase lacking the highly conserved lysine residue

    DOE PAGESBeta

    Teixeira, Miguel; Cabelli, Diane; Pinto, Ana F.; Romao, Celia V.; Pinto, Liliana C.; Huber, Harald; Saraiva, Ligia M.; Todorovic, Smilja

    2015-01-01

    Superoxide reductases (SORs) are the most recently identified superoxide detoxification systems, being found in microorganisms from the three domains of life. These enzymes are characterized by a catalytic mononuclear iron site, with one cysteine and four histidine ligands of the ferrous active form. A lysine residue in the –EKHVP– motif, located close to the active site, has been considered to be essential for the enzyme function, by contributing to the positive surface patch that attracts the superoxide anion and by controlling the chemistry of the catalytic mechanism through a hydrogen bond network. However, we show here that this residue ismore »substituted by non-equivalent amino acids in several putative SORs from Archaea and unicellular Eukarya. In this work, we focus on mechanistic and spectroscopic studies of one of these less common enzymes, the SOR from the hyperthermophilic crenarchaeon Ignicoccus hospitalis. We employ pulse radiolysis fast kinetics and spectroscopic approaches to study the wild-type enzyme (?E??T??HVP?), and two mutants, T24K and E23A, the later mimicking enzymes lacking both the lysine and glutamate (a ferric ion ligand) of the motif. The efficiency of the wild type protein and mutants in reducing superoxide is comparable to other SORs, revealing the robustness of these enzymes to single mutations.« less

  8. Role of Methionine Sulfoxide Reductases A and B of Enterococcus faecalis in Oxidative Stress and Virulence ?

    PubMed Central

    Zhao, Chen; Hartke, Axel; La Sorda, Marilena; Posteraro, Brunella; Laplace, Jean-Marie; Auffray, Yanick; Sanguinetti, Maurizio

    2010-01-01

    Methionine sulfoxide reductases A and B are antioxidant repair enzymes that reduce the S- and R-diastereomers of methionine sulfoxides back to methionine, respectively. Enterococcus faecalis, an important nosocomial pathogen, has one msrA gene and one msrB gene situated in different parts of the chromosome. Promoters have been mapped and mutants have been constructed in two E. faecalis strains (strains JH2-2 and V583) and characterized. For both backgrounds, the mutants are more sensitive than the wild-type parents to exposure to H2O2, and in combination the mutations seem to be additive. The virulence of the mutants has been analyzed in four different models. Survival of the mutants inside mouse peritoneal macrophages stimulated with recombinant gamma interferon plus lipopolysaccharide but not in naïve phagocytes is significantly affected. The msrA mutant is attenuated in the Galleria mellonella insect model. Deficiency in either Msr enzyme reduced the level of virulence in a systemic and urinary tract infection model. Virulence was reconstituted in the complemented strains. The combined results show that Msr repair enzymes are important for the oxidative stress response, macrophage survival, and persistent infection with E. faecalis. PMID:20566694

  9. Distinct cinnamoyl CoA reductases involved in parallel routes to lignin in Medicago truncatula.

    PubMed

    Zhou, Rui; Jackson, Lisa; Shadle, Gail; Nakashima, Jin; Temple, Stephen; Chen, Fang; Dixon, Richard A

    2010-10-12

    Cinnamoyl CoA reductases (CCR) convert hydroxycinnamoyl CoA esters to their corresponding cinnamyl aldehydes in monolignol biosynthesis. We identified two CCR genes in the model legume Medicago truncatula. CCR1 exhibits preference for feruloyl CoA, but CCR2 prefers caffeoyl and 4-coumaroyl CoAs, exhibits sigmoidal kinetics with these substrates, and is substrate-inhibited by feruloyl and sinapoyl CoAs. M. truncatula lines harboring transposon insertions in CCR1 exhibit drastically reduced growth and lignin content, whereas CCR2 knockouts grow normally with moderate reduction in lignin levels. CCR1 fully and CCR2 partially complement the irregular xylem gene 4 CCR mutation of Arabidopsis. The expression of caffeoyl CoA 3-O-methyltransferase (CCoAOMT) is up-regulated in CCR2 knockout lines; conversely, knockout of CCoAOMT up-regulates CCR2. These observations suggest that CCR2 is involved in a route to monolignols in Medicago whereby coniferaldehyde is formed via caffeyl aldehyde which then is 3-O-methylated by caffeic acid O-methyltransferase. PMID:20876124

  10. Superoxide reduction by a superoxide reductase lacking the highly conserved lysine residue

    SciTech Connect

    Teixeira, Miguel [Univ. Nova de Lisboa, Oeiras (Portugal); Cabelli, Diane [Brookhaven National Lab. (BNL), Upton, NY (United States); Pinto, Ana F. [Univ. Nova de Lisboa, Oeiras (Portugal); Karolinska Inst., Stockholm (Sweden); Romao, Celia V. [Univ. Nova de Lisboa, Oeiras (Portugal); Pinto, Liliana C. [Univ. Nova de Lisboa, Oeiras (Portugal); Huber, Harald [Univ. Regensburg, Regensburg (Germany); Saraiva, Ligia M. [Univ. Nova de Lisboa, Oeiras (Portugal); Todorovic, Smilja [Univ. Nova de Lisboa, Oeiras (Portugal)

    2015-01-01

    Superoxide reductases (SORs) are the most recently identified superoxide detoxification systems, being found in microorganisms from the three domains of life. These enzymes are characterized by a catalytic mononuclear iron site, with one cysteine and four histidine ligands of the ferrous active form. A lysine residue in the –EKHVP– motif, located close to the active site, has been considered to be essential for the enzyme function, by contributing to the positive surface patch that attracts the superoxide anion and by controlling the chemistry of the catalytic mechanism through a hydrogen bond network. However, we show here that this residue is substituted by non-equivalent amino acids in several putative SORs from Archaea and unicellular Eukarya. In this work, we focus on mechanistic and spectroscopic studies of one of these less common enzymes, the SOR from the hyperthermophilic crenarchaeon Ignicoccus hospitalis. We employ pulse radiolysis fast kinetics and spectroscopic approaches to study the wild-type enzyme (?E??T??HVP?), and two mutants, T24K and E23A, the later mimicking enzymes lacking both the lysine and glutamate (a ferric ion ligand) of the motif. The efficiency of the wild type protein and mutants in reducing superoxide is comparable to other SORs, revealing the robustness of these enzymes to single mutations.

  11. Mutation and Extinction: The Role of Variable Mutational Effects, Synergistic Epistasis, Beneficial Mutations, and Degree of Outcrossing

    E-print Network

    Lynch, Michael

    Mutation and Extinction: The Role of Variable Mutational Effects, Synergistic Epistasis, Beneficial AND EXTINCTION: THE ROLE OF VARIABLE MUTATIONAL EFFECTS, SYNERGISTIC EPISTASIS, BENEFICIAL MUTATIONS of extinction. These include the presence of synergistic epistasis, which can reduce the rate of mutation

  12. Genetic and biochemical characterization of mutations affecting the ability of the yeast Pachysolen tannophilus to metabolize D-xylose

    SciTech Connect

    James, A.P.; Zahab, D.M.; Mahmourides, G.; Maleszka, R.; Schneider, H. (National Research Council of Canada, Ottawa, Ontario (Canada))

    1989-11-01

    Induced mutants, selected for their defective growth on D-xylose while retaining the ability to grow normally on D-glucose, were studied in Pachysolen tannophilus, a yeast capable of converting D-xylose to ethanol. Fourteen of the mutations were found to occur at nine distinct loci, and data indicated that many more loci remain to be detected. Most of the mutations were pleiotropic in character, and the expression of some of them was much affected by nutritional conditions and by genetic background. Mutations at several loci resulted in poor growth on at least one compound that was either an intermediate of the tricarboxylic acid cycle, succinate or {alpha}-ketoglutarate, or on compounds metabolizable via this cycle, ethanol or glycerol. An initial biochemical characterization of the mutants was undertaken. Analysis for xylose reductase, xylitol dehydrogenase, and xylulose kinase activity showed that one or more of these activities was affected in 12 of 13 mutants. However, drastic reduction in activity of a single enzyme was confined to that of xylitol dehydrogenase by mutations at three different loci and to that of D-xylose reductase by mutation at another locus. Growth of these latter four mutants was normal on all carbon sources tested that were not five-carbon sugars.

  13. Kinetic characteristics of ZENECA ZD5522, a potent inhibitor of human and bovine lens aldose reductase.

    PubMed

    Cook, P N; Ward, W H; Petrash, J M; Mirrlees, D J; Sennitt, C M; Carey, F; Preston, J; Brittain, D R; Tuffin, D P; Howe, R

    1995-04-18

    Aldose reductase (aldehyde reductase 2) catalyses the conversion of glucose to sorbitol, and methylglyoxal to acetol. Treatment with aldose reductase inhibitors (ARIs) is a potential approach to decrease the development of diabetic complications. The sulphonylnitromethanes are a recently discovered class of aldose reductase inhibitors, first exemplified by ICI215918. We now describe enzyme kinetic characterization of a second sulphonylnitromethane, 3',5'-dimethyl-4'-nitromethylsulphonyl-2-(2-tolyl)acetanilide (ZD5522), which is at least 10-fold more potent against bovine lens aldose reductase in vitro and which also has a greater efficacy for reduction of rat nerve sorbitol levels in vivo (ED95 = 2.8 mg kg-1 for ZD5522 and 20 mg kg-1 for ICI 215918). ZD5522 follows pure noncompetitive kinetics against bovine lens aldose reductase when either glucose or methylglyoxal is varied (K(is) = K(ii) = 7.2 and 4.3 nM, respectively). This contrasts with ICI 215918 which is an uncompetitive inhibitor (K(ii) = 100 nM) of bovine lens aldose reductase when glucose is varied. Against human recombinant aldose reductase, ZD5522 displays mixed noncompetitive kinetics with respect to both substrates (K(is) = 41 nM, K(ii) = 8 nM with glucose and K(is) = 52 nM, K(ii) = 3.8 nM with methylglyoxal). This is the first report of the effects of a sulphonylnitromethane on either human aldose reductase or utilization of methylglyoxal. These results are discussed with reference to a Di Iso Ordered Bi Bi mechanism for aldose reductase, where the inhibitors compete with binding of both the aldehyde substrate and alcohol product. This model may explain why aldose reductase inhibitors follow noncompetitive or uncompetitive kinetics with respect to aldehyde substrates, and X-ray crystallography paradoxically locates an ARI within the substrate binding site. Aldehyde reductase (aldehyde reductase 1) is closely related to aldose reductase. Inhibition of bovine kidney aldehyde reductase by ZD5522 follows uncompetitive kinetics with respect to glucuronate (K(ii) = 39 nM), indicating a selectivity greater than 5-fold for bovine aldose reductase relative to aldehyde reductase. PMID:7748183

  14. Amino acid residues in Anabaena ferredoxin crucial to interaction with ferredoxin-NADP+ reductase: site-directed mutagenesis and laser flash photolysis.

    PubMed

    Hurley, J K; Salamon, Z; Meyer, T E; Fitch, J C; Cusanovich, M A; Markley, J L; Cheng, H; Xia, B; Chae, Y K; Medina, M

    1993-09-14

    Ferredoxin (Fd) functions in photosynthesis to transfer electrons from photosystem I to ferredoxin-NADP+ reductase (FNR). We have made several site-directed mutants of Anabaena 7120 Fd and have used laser flash photolysis to investigate the effects of these mutations on the kinetics of reduction of oxidized Fd by deazariboflavin semiquinone (dRfH.) and the reduction of oxidized Anabaena FNR by reduced Fd. None of the mutations influenced the second-order rate constant for dRfH. reduction by more than a factor of 2, suggesting that the ability of the [2Fe-2S] cluster to participate in electron transfer was not seriously affected. In contrast, a surface charge reversal mutation, E94K, resulted in a 20,000-fold decrease in the second-order rate constant for electron transfer from Fd to FNR, whereas a similar mutation at an adjacent site, E95K, produced little or no change in reaction rate constant compared to wild-type Fd. Such a dramatic difference between contiguous surface mutations suggests a very precise surface complementarity at the protein-protein interface. Mutations introduced at F65 (F65I and F65A) also decreased the rate constant for the Fd/FNR electron transfer reaction by more than 3 orders of magnitude. Spectroscopic and thermodynamic measurements with both the E94 and F65 mutants indicated that the kinetic differences cannot be ascribed to changes in gross conformation, redox potential, or FNR binding constant but rather reflect the protein-protein interactions that control electron transfer. Several mutations at other sites in the vicinity of E94 and F65 (R42, T48, D68, and D69) resulted in little or no perturbation of the Fd/FNR interaction.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8369305

  15. Selenite reduction by Shewanella oneidensis MR-1 is mediated by fumarate reductase in periplasm

    NASA Astrophysics Data System (ADS)

    Li, Dao-Bo; Cheng, Yuan-Yuan; Wu, Chao; Li, Wen-Wei; Li, Na; Yang, Zong-Chuang; Tong, Zhong-Hua; Yu, Han-Qing

    2014-01-01

    In situ reduction of selenite to elemental selenium (Se(0)), by microorganisms in sediments and soils is an important process and greatly affects the environmental distribution and the biological effects of selenium. However, the mechanism behind such a biological process remains unrevealed yet. Here we use Shewanella oneidensis MR-1, a widely-distributed dissimilatory metal-reducing bacterium with a powerful and diverse respiration capability, to evaluate the involvement of anaerobic respiration system in the microbial selenite reduction. With mutants analysis, we identify fumarate reductase FccA as the terminal reductase of selenite in periplasm. Moreover, we find that such a reduction is dependent on central respiration c-type cytochrome CymA. In contrast, nitrate reductase, nitrite reductase, and the Mtr electron transfer pathway do not work as selenite reductases. These findings reveal a previously unrecognized role of anaerobic respiration reductases of S. oneidensis MR-1 in selenite reduction and geochemical cycles of selenium in sediments and soils.

  16. Mycobacterium tuberculosis dihydrofolate reductase is a target for isoniazid

    Microsoft Academic Search

    Argyrides Argyrou; Matthew W Vetting; Bola Aladegbami; John S Blanchard

    2006-01-01

    Isoniazid is a key drug used in the treatment of tuberculosis. Isoniazid is a pro-drug, which, after activation by the katG-encoded catalase peroxidase, reacts nonenzymatically with NAD+ and NADP+ to generate several isonicotinoyl adducts of these pyridine nucleotides. One of these, the acyclic 4S isomer of isoniazid-NAD, targets the inhA-encoded enoyl-ACP reductase, an enzyme essential for mycolic acid biosynthesis in

  17. Methionine Sulfoxide Reductase B Displays a High Level of Flexibility

    Microsoft Academic Search

    Fanomezana M. Ranaivoson; Fabrice Neiers; Brice Kauffmann; Sandrine Boschi-Muller; Guy Branlant; Frédérique Favier

    2009-01-01

    Methionine sulfoxide reductases (Msrs) are enzymes that catalyze the reduction of methionine sulfoxide back to methionine. In vivo, Msrs are essential in the protection of cells against oxidative damage to proteins and in the virulence of some bacteria. Two structurally unrelated classes of Msrs, named MsrA and MsrB, exist. MsrB are stereospecific to R epimer on the sulfur of sulfoxide.

  18. Glutathione Reductase: A Putative Redox Regulatory System in Plant Cells

    Microsoft Academic Search

    A. S. V. Chalapathi Rao; Attipalli R. Reddy

    Glutathione reductase (GR, EC 1.6.4.2) and glutathione (GSH, ?-Glu-Cys-Gly) are important components of the cell’s scavenging\\u000a system for reactive oxygen compounds in plants. GSH is a major reservoir of nonprotein reduced sulfur. In addition, GSH plays\\u000a a crucial role in cellular defense, where it gets oxidized to glutathione disulfide (GSSG). GR mediates the reduction of GSSG\\u000a to GSH by using

  19. Pleiotropic effects of the HMG-CoA reductase inhibitors

    PubMed Central

    Mihos, Christos G; Santana, Orlando

    2011-01-01

    The HMG-CoA reductase inhibitors (statins) are used extensively in the treatment of hyperlipidemia. They have also demonstrated a benefit in a variety of other disease processes. These secondary actions are known as pleiotropic effects. Our paper serves as a focused and updated discussion on the pleiotropy of statins and emphasizes the importance of randomized placebo-controlled trials to further elucidate this interesting phenomenon. PMID:21556312

  20. Identification of disulfide reductases in Campylobacterales: a bioinformatics investigation

    Microsoft Academic Search

    Nadeem O. Kaakoush; Torsten Sterzenbach; William G. Miller; Sebastian Suerbaum; George Louis Mendz

    2007-01-01

    Disulfide reductases of host-colonising bacteria are involved in the expression of virulence factors, resistance to drugs,\\u000a and elimination of toxic compounds. Large-scale genome analyses of 281 prokaryotes identified CXXC and CXXC-derived motifs\\u000a in each microorganism. The total number of these motifs showed correlations with genome size and oxygen tolerance of the prokaryotes.\\u000a Specific bioinformatic analyses served to identify putative disulfide

  1. Glutathione reductase: solvent equilibrium and kinetic isotope effects

    SciTech Connect

    Wong, K.K.; Vanoni, M.A.; Blanchard, J.S.

    1988-09-06

    Glutathione reductase catalyzes the NADPH-dependent reduction of oxidized glutathione (GSSG). The kinetic mechanism is ping-pong, and we have investigated the rate-limiting nature of proton-transfer steps in the reactions catalyzed by the spinach, yeast, and human erythrocyte glutathione reductases using a combination of alternate substrate and solvent kinetic isotope effects. With NADPH or GSSG as the variable substrate, at a fixed, saturating concentration of the other substrate, solvent kinetic isotope effects were observed on V but not V/K. Plots of Vm vs mole fraction of D2O (proton inventories) were linear in both cases for the yeast, spinach, and human erythrocyte enzymes. When solvent kinetic isotope effect studies were performed with DTNB instead of GSSG as an alternate substrate, a solvent kinetic isotope effect of 1.0 was observed. Solvent kinetic isotope effect measurements were also performed on the asymmetric disulfides GSSNB and GSSNP by using human erythrocyte glutathione reductase. The Km values for GSSNB and GSSNP were 70 microM and 13 microM, respectively, and V values were 62 and 57% of the one calculated for GSSG, respectively. Both of these substrates yield solvent kinetic isotope effects greater than 1.0 on both V and V/K and linear proton inventories, indicating that a single proton-transfer step is still rate limiting. These data are discussed in relationship to the chemical mechanism of GSSG reduction and the identity of the proton-transfer step whose rate is sensitive to solvent isotopic composition. Finally, the solvent equilibrium isotope effect measured with yeast glutathione reductase is 4.98, which allows us to calculate a fractionation factor for the thiol moiety of GSH of 0.456.

  2. The mechanism of high Mr thioredoxin reductase from Drosophila melanogaster.

    PubMed

    Bauer, Holger; Massey, Vincent; Arscott, L David; Schirmer, R Heiner; Ballou, David P; Williams, Charles H

    2003-08-29

    Drosophila melanogaster thioredoxin reductase-1 (DmTrxR-1) is a key flavoenzyme in dipteran insects, where it substitutes for glutathione reductase. DmTrxR-1 belongs to the family of dimeric, high Mr thioredoxin reductases, which catalyze reduction of thioredoxin by NADPH. Thioredoxin reductase has an N-terminal redox-active disulfide (Cys57-Cys62) adjacent to the flavin and a redox-active C-terminal cysteine pair (Cys489'-Cys490' in the other subunit) that transfer electrons from Cys57-Cys62 to the substrate thioredoxin. Cys489'-Cys490' functions similarly to Cys495-Sec496 (Sec = selenocysteine) and Cys535-XXXX-Cys540 in human and parasite Plasmodium falciparum enzymes, but a catalytic redox center formed by adjacent Cys residues, as observed in DmTrxR-1, is unprecedented. Our data show, for the first time in a high Mr TrxR, that DmTrxR-1 oscillates between the 2-electron reduced state, EH2, and the 4-electron state, EH4, in catalysis, after the initial priming reduction of the oxidized enzyme (Eox) to EH2. The reductive half-reaction consumes 2 eq of NADPH in two observable steps to produce EH4. The first equivalent yields a FADH--NADP+ charge-transfer complex that reduces the adjacent disulfide to form a thiolate-flavin charge-transfer complex. EH4 reacts with thioredoxin rapidly to produce EH2. In contrast, Eox formation is slow and incomplete; thus, EH2 of wild-type cannot reduce thioredoxin at catalytically competent rates. Mutants lacking the C-terminal redox center, C489S, C490S, and C489S/C490S, are incapable of reducing thioredoxin and can only be reduced to EH2 forms. Additional data suggest that Cys57 attacks Cys490' in the interchange reaction between the N-terminal dithiol and the C-terminal disulfide. PMID:12816954

  3. Old and new inhibitors of quinone reductase 2

    Microsoft Academic Search

    Gilles Ferry; Sabrina Hecht; Sylvie Berger; Natacha Moulharat; Francis Coge; Gérald Guillaumet; Véronique Leclerc; Saïd Yous; Philippe Delagrange; Jean A. Boutin

    2010-01-01

    Quinone reductase 2 is a cytosolic enzyme which catalyses the reduction of quinones, such as menadione and coenzymes Q. Despite a relatively close sequence-based resemblance to NAD(P)H:quinone oxidoreductase 1 (QR1), it has many different features. QR2 is the third melatonin binding site (MT3). It is inhibited in the micromolar range by melatonin, and does not accept conventional phosphorylated nicotinamides as

  4. Phosphoglycerate kinase acts in tumour angiogenesis as a disulphide reductase

    NASA Astrophysics Data System (ADS)

    Lay, Angelina J.; Jiang, Xing-Mai; Kisker, Oliver; Flynn, Evelyn; Underwood, Anne; Condron, Rosemary; Hogg, Philip J.

    2000-12-01

    Disulphide bonds in secreted proteins are considered to be inert because of the oxidizing nature of the extracellular milieu. An exception to this rule is a reductase secreted by tumour cells that reduces disulphide bonds in the serine proteinase plasmin. Reduction of plasmin initiates proteolytic cleavage in the kringle 5 domain and release of the tumour blood vessel inhibitor angiostatin. New blood vessel formation or angiogenesis is critical for tumour expansion and metastasis. Here we show that the plasmin reductase isolated from conditioned medium of fibrosarcoma cells is the glycolytic enzyme phosphoglycerate kinase. Recombinant phosphoglycerate kinase had the same specific activity as the fibrosarcoma-derived protein. Plasma of mice bearing fibrosarcoma tumours contained several-fold more phosphoglycerate kinase, as compared with mice without tumours. Administration of phosphoglycerate kinase to tumour-bearing mice caused an increase in plasma levels of angiostatin, and a decrease in tumour vascularity and rate of tumour growth. Our findings indicate that phosphoglycerate kinase not only functions in glycolysis but is secreted by tumour cells and participates in the angiogenic process as a disulphide reductase.

  5. Targeting 5?-reductase for prostate cancer prevention and treatment

    PubMed Central

    Nacusi, Lucas P.; Tindall, Donald J.

    2014-01-01

    Testosterone is the most abundant circulating androgen, and can be converted to dihydrotestosterone (DHT), a more potent androgen, by the 5?-reductase enzymes in target tissues. Current treatments for prostate cancer consist of reducing androgen levels by chemical or surgical castration or pure antiandrogen therapy that directly targets the androgen receptor (AR). Although these therapies reduce tumor burden and AR activity, the cancer inevitably recurs within 18–30 months. An approach targeting the androgen–AR axis at different levels could, therefore, improve the efficacy of prostate cancer therapy. Inhibition of 5?-reductase is one such approach; however, the two largest trials to investigate the use of the 5?-reductase inhibitors (5ARIs) finasteride and dutasteride in patients with prostate cancer have shown that, although the incidence of cancer was reduced by 5ARI treatment, those cancers that were detected were more aggressive than in patients treated with placebo. Thus, the best practice for using these drugs to prevent and treat prostate cancer remains unclear. PMID:21629218

  6. Using chemical approaches to study selenoproteins - focus on thioredoxin reductases

    PubMed Central

    Hondal, Robert J.

    2009-01-01

    The study of selenocysteine-containing proteins is difficult due to the problems associated with the heterologous production of these proteins. These problems are due to the intricate recoding mechanism used by cells to translate the UGA codon as a sense codon for selenocysteine. The process is further complicated by the fact that eukaryotes and prokaryotes have different UGA recoding machineries. This review focuses on chemical approaches to produce selenoproteins and study the mechanism of selenoenzymes. The use of intein-mediated peptide ligation is discussed with respect to the production of the mammalian selenoenzymes thioredoxin reductase and selenoprotein R, also known as methionine sulfoxide reductase B1. New methods for removing protecting groups from selenocysteine post-synthesis and methods for selenosulfide/diselenide formation are also reviewed. Chemical approaches have also been used to study the enzymatic mechanism of thioredoxin reductase. The approach divides the enzyme into two modules, a large protein module lacking selenocysteine and a small, synthetic selenocysteine-containing peptide. Study of this semisynthetic enzyme has revealed three distinct enzymatic pathways that depend on the properties of the substrate. The enzyme utilizes a macromolecular mechanism for protein substrates, a second mechanism for small molecule substrates and a third pathway for selenium-containing substrates such as selenocystine. PMID:19406205

  7. Active site modification of aldose reductase by nitric oxide donors.

    PubMed

    Chandra, A; Srivastava, S; Petrash, J M; Bhatnagar, A; Srivastava, S K

    1997-09-01

    Nitric oxide (NO) donors sodium nitrosoprusside (SNP), S-nitroso-N-acetylpenicillamine (SNAP), and 3-morpholinosydnonemine (SIN-1) caused a time- and concentration-dependent loss of catalytic activity of recombinant human placental aldose reductase. Modification of the enzyme was prevented by NADPH and NADP and reversed partially by dithiothreitol (DTT) and sodium borohydride. The protection by NADPH was lost in the presence of both substrates (NADPH and glyceraldehyde), indicating that the enzyme becomes sensitive to inhibition by SNP during catalysis. Site-directed mutant form of the enzyme, in which active site cys-298 was substituted with serine (C298S) was not inactivated by NO donors, whereas, ARC80S and ARC303 were as sensitive as the wild type enzyme, indicating that inactivation of aldose reductase is due to modification of the active site at cys298. These results suggest that NO may be an endogenous regulator of aldose reductase, and consequently the polyol pathway of glucose metabolism; which has been implicated in the pathogenesis of secondary diabetic complications. PMID:9357961

  8. Fitness Causes Bloat: Mutation

    Microsoft Academic Search

    William B. Langdon; Riccardo Poli

    1998-01-01

    The problem of evolving, using mutation, an artificial ant to follow the Santa Fe trail is used to study the well known genetic program- ming feature of growth in solution length. Known variously as \\

  9. Periplasmic Nitrate Reductase (NapABC Enzyme) Supports Anaerobic Respiration by Escherichia coli K-12

    Microsoft Academic Search

    Valley Stewart; Yiran Lu; Andrew J. Darwin

    2002-01-01

    Periplasmic nitrate reductase (NapABC enzyme) has been characterized from a variety of proteobacteria, especially Paracoccus pantotrophus. Whole-genome sequencing of Escherichia coli revealed the structural genes napFDAGHBC, which encode NapABC enzyme and associated electron transfer components. E. coli also ex- presses two membrane-bound proton-translocating nitrate reductases, encoded by the narGHJI and narZYWV operons. We measured reduced viologen-dependent nitrate reductase activity in

  10. Synergy between broccoli sprout extract and selenium in the upregulation of thioredoxin reductase in human hepatocytes

    Microsoft Academic Search

    Dan Li; Kun Wu; A. Forbes Howie; Geoffrey J. Beckett; Wei Wang; Yongping Bao

    2008-01-01

    Dietary isothiocyanates and selenium (Se) can up-regulate thioredoxin reductase 1 (TR1) in cultured human HepG2 and MCF-7 cells [Zhang et al. (2003). Synergy between sulforaphane and selenium in the induction of thioredoxin reductase 1 requires both transcriptional and translational modulation. Carcinogenesis, 24, 497–503; Wang et al. (2005). Sulforaphane, erucin and iberin up-regulate thioredoxin reductase expression in human MCF-7 cells. Journal

  11. Benzofuranyl 3,5-bis-Polyamine Derivatives as Time-Dependent Inhibitors of Trypanothione Reductase

    E-print Network

    Schnaufer, Achim

    -g-glutamyl-l-cysteinyl- glycine) and glutathione disulfide reductase (GR; EC 1.6.4.2), is replaced in trypanosomatids by an analo reductase (TryR; EC 1.6.4.8). The structures of the disulfide substrates for TryR and GR are illustratedBenzofuranyl 3,5-bis-Polyamine Derivatives as Time-Dependent Inhibitors of Trypanothione Reductase

  12. The role of tryptophan in the ferredoxin-dependent nitrite reductase of spinach

    Microsoft Academic Search

    Jatindra N. Tripathy; Masakazu Hirasawa; Sung-Kun Kim; Aaron T. Setterdahl; James P. Allen; David B. Knaff

    2007-01-01

    A system has been developed for expressing a His-tagged form of the ferredoxin-dependent nitrite reductase of spinach in Escherichia coli. The catalytic and spectral properties of the His-tagged, recombinant enzyme are similar, but not identical, to those previously\\u000a observed for nitrite reductase isolated directly from spinach leaf. A detailed comparison of the spectral, catalytic and fluorescence\\u000a properties of nitrite reductase

  13. Rates of spontaneous mutation.

    PubMed Central

    Drake, J W; Charlesworth, B; Charlesworth, D; Crow, J F

    1998-01-01

    Rates of spontaneous mutation per genome as measured in the laboratory are remarkably similar within broad groups of organisms but differ strikingly among groups. Mutation rates in RNA viruses, whose genomes contain ca. 10(4) bases, are roughly 1 per genome per replication for lytic viruses and roughly 0.1 per genome per replication for retroviruses and a retrotransposon. Mutation rates in microbes with DNA-based chromosomes are close to 1/300 per genome per replication; in this group, therefore, rates per base pair vary inversely and hugely as genome sizes vary from 6 x 10(3) to 4 x 10(7) bases or base pairs. Mutation rates in higher eukaryotes are roughly 0.1-100 per genome per sexual generation but are currently indistinguishable from 1/300 per cell division per effective genome (which excludes the fraction of the genome in which most mutations are neutral). It is now possible to specify some of the evolutionary forces that shape these diverse mutation rates. PMID:9560386

  14. Structure and reactivity of Trypanosoma brucei pteridine reductase: inhibition by the archetypal

    E-print Network

    Schnaufer, Achim

    reductase and therefore compromises the use of antifolates for treat- ment of trypanosomiasis. Catalytic trypanosomiasis. Introduction Trypanosomatid protozoans are auxotrophic for folate and other pterins (Kidder

  15. A flavone from Manilkara indica as a specific inhibitor against aldose reductase in vitro.

    PubMed

    Haraguchi, Hiroyuki; Hayashi, Ryosuke; Ishizu, Takashi; Yagi, Akira

    2003-09-01

    Isoaffinetin (5,7,3',4',5'-pentahydroxyflavone-6-C-glucoside) was isolated from Manilkara indica as a potent inhibitor of lens aldose reductase by bioassay-directed fractionation. This C-glucosyl flavone showed specific inhibition against aldose reductases (rat lens, porcine lens and recombinant human) with no inhibition against aldehyde reductase and NADH oxidase. Kinetic analysis showed that isoaffinetin exhibited uncompetitive inhibition against both dl-glyceraldehyde and NADPH. A structure-activity relationship study revealed that the increasing number of hydroxy groups in the B-ring contributes to the increase in aldose reductase inhibition by C-glucosyl flavones. PMID:14598214

  16. Structure of the Molybdenum Site of EEcherichia Coli Trimethylamine N-Oxide Reductase

    SciTech Connect

    Zhang, L.; Nelson, K.Johnson; Rajagopalan, K.V.; George, G.N.

    2009-05-28

    We report a structural characterization of the molybdenum site of recombinant Escherichia coli trimethylamine N-oxide (TMAO) reductase using X-ray absorption spectroscopy. The enzyme active site shows considerable similarity to that of dimethyl sulfoxide (DMSO) reductase, in that, like DMSO reductase, the TMAO reductase active site can exist in multiple forms. Examination of the published crystal structure of TMAO oxidase from Shewanella massilia indicates that the postulated Mo coordination structure is chemically impossible. The presence of multiple active site structures provides a potential explanation for the anomalous features reported from the crystal structure.

  17. A proposed reaction mechanism for rice NADPH thioredoxin reductase C, an enzyme with protein disulfide reductase activity

    Microsoft Academic Search

    Juan Manuel Pérez-Ruiz; Francisco Javier Cejudo

    2009-01-01

    NADPH thioredoxin reductase C (NTRC) is an interesting NTR with a thioredoxin (Trx) domain at the C-terminus, able to conjugate both activities for 2-Cys peroxiredoxin (Prx) reduction. NTRC is dimeric in the presence of NADPH and interacted with dimeric 2-Cys Prx through the Trx module by a mixed disulfide between Cys377 of NTRC and Cys61 of the 2-Cys Prx. NTRC

  18. Methionine Sulfoxide Reductases Are Essential for Virulence of Salmonella Typhimurium

    PubMed Central

    Rouf, Syed Fazle; Kitowski, Vera; Böhm, Oliver M.; Rhen, Mikael; Jäger, Timo; Bange, Franz-Christoph

    2011-01-01

    Production of reactive oxygen species represents a fundamental innate defense against microbes in a diversity of host organisms. Oxidative stress, amongst others, converts peptidyl and free methionine to a mixture of methionine-S- (Met-S-SO) and methionine-R-sulfoxides (Met-R-SO). To cope with such oxidative damage, methionine sulfoxide reductases MsrA and MsrB are known to reduce MetSOs, the former being specific for the S-form and the latter being specific for the R-form. However, at present the role of methionine sulfoxide reductases in the pathogenesis of intracellular bacterial pathogens has not been fully detailed. Here we show that deletion of msrA in the facultative intracellular pathogen Salmonella (S.) enterica serovar Typhimurium increased susceptibility to exogenous H2O2, and reduced bacterial replication inside activated macrophages, and in mice. In contrast, a ?msrB mutant showed the wild type phenotype. Recombinant MsrA was active against free and peptidyl Met-S-SO, whereas recombinant MsrB was only weakly active and specific for peptidyl Met-R-SO. This raised the question of whether an additional Met-R-SO reductase could play a role in the oxidative stress response of S. Typhimurium. MsrC is a methionine sulfoxide reductase previously shown to be specific for free Met-R-SO in Escherichia (E.) coli. We tested a ?msrC single mutant and a ?msrB?msrC double mutant under various stress conditions, and found that MsrC is essential for survival of S. Typhimurium following exposure to H2O2, as well as for growth in macrophages, and in mice. Hence, this study demonstrates that all three methionine sulfoxide reductases, MsrA, MsrB and MsrC, facilitate growth of a canonical intracellular pathogen during infection. Interestingly MsrC is specific for the repair of free methionine sulfoxide, pointing to an important role of this pathway in the oxidative stress response of Salmonella Typhimurium. PMID:22073230

  19. Methionine sulfoxide reductases are essential for virulence of Salmonella typhimurium.

    PubMed

    Denkel, Luisa A; Horst, Sarah A; Rouf, Syed Fazle; Kitowski, Vera; Böhm, Oliver M; Rhen, Mikael; Jäger, Timo; Bange, Franz-Christoph

    2011-01-01

    Production of reactive oxygen species represents a fundamental innate defense against microbes in a diversity of host organisms. Oxidative stress, amongst others, converts peptidyl and free methionine to a mixture of methionine-S- (Met-S-SO) and methionine-R-sulfoxides (Met-R-SO). To cope with such oxidative damage, methionine sulfoxide reductases MsrA and MsrB are known to reduce MetSOs, the former being specific for the S-form and the latter being specific for the R-form. However, at present the role of methionine sulfoxide reductases in the pathogenesis of intracellular bacterial pathogens has not been fully detailed. Here we show that deletion of msrA in the facultative intracellular pathogen Salmonella (S.) enterica serovar Typhimurium increased susceptibility to exogenous H(2)O(2), and reduced bacterial replication inside activated macrophages, and in mice. In contrast, a ?msrB mutant showed the wild type phenotype. Recombinant MsrA was active against free and peptidyl Met-S-SO, whereas recombinant MsrB was only weakly active and specific for peptidyl Met-R-SO. This raised the question of whether an additional Met-R-SO reductase could play a role in the oxidative stress response of S. Typhimurium. MsrC is a methionine sulfoxide reductase previously shown to be specific for free Met-R-SO in Escherichia (E.) coli. We tested a ?msrC single mutant and a ?msrB?msrC double mutant under various stress conditions, and found that MsrC is essential for survival of S. Typhimurium following exposure to H(2)O(2,) as well as for growth in macrophages, and in mice. Hence, this study demonstrates that all three methionine sulfoxide reductases, MsrA, MsrB and MsrC, facilitate growth of a canonical intracellular pathogen during infection. Interestingly MsrC is specific for the repair of free methionine sulfoxide, pointing to an important role of this pathway in the oxidative stress response of Salmonella Typhimurium. PMID:22073230

  20. Identical mutations and phenotypic variation

    Microsoft Academic Search

    Ulrich Wolf

    1997-01-01

    The relationship between pathogenetic mutations and disease phenotype is becoming increasingly complex. Well-delineated clinical\\u000a entities can be genetically heterogeneous, and mutations in a particular gene may result in fundamental clinical differences.\\u000a Genetic heterogeneity includes mutations at different gene loci or allelic mutations within a single gene, resulting in a\\u000a similar phenotype. However, one and the same mutation is expected to