Functional Genomics of C190T Single Nucleotide Polymorphism in Human N-Acetyltransferase 2

2002 ◽  
Vol 383 (6) ◽  
pp. 983-987 ◽  
Author(s):  
Yuanqi Zhu ◽  
Mark A. Doll ◽  
David W. Hein

Abstract Nacetyltransferase 2 (NAT2) catalyzes Nacetylation and Oacetylation of many drugs and environmental carcinogens. Genetic polymorphisms in the NAT2 gene have been associated with differential susceptibility to cancers and drug toxicity from these compounds. Single nucleotide polymorphisms (SNPs) have been identified in the human NAT2 coding region. A new allele, NAT2*19, possessing the C190T (R64W) exchange, was recently identified. In order to understand the effect of this new SNP, recombinant NAT2*4 (reference) and NAT2*19 were expressed in yeast (Schizosaccharomyces pombe). The C190T (R64W) SNP in NAT2*19 caused substantial reduction in the NAT2 protein level and stability, but did not cause significant reduction in transformation efficiency or mRNA level. The enzymatic activities for Nacetylation of two arylamine carcinogens (2-aminofluorene, 4-aminobiphenyl), and a sulfonamide drug (sulfamethazine) were over 100-fold lower for NAT2 19 compared to reference NAT2 4. Kinetic studies showed a reduction in Vmax but no significant change in substrate Km. In addition, the SNP caused significant reduction in the Oacetylation of the Nhydroxy 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine. These results show that NAT2*19 possessing the C190T (R64W) SNP encodes a slow acetylator phenotype for both N and Oacetylation, due to a reduction in the amount and stability of the NAT2 19 allozyme.

2004 ◽  
Vol 1 (3) ◽  
pp. 181-190 ◽  
Author(s):  
Hao Gang-Ping ◽  
Wu Zhong-Yi ◽  
Chen Mao-Sheng ◽  
Cao Ming-Qing ◽  
Dominique Brunel ◽  
...  

AbstractThe levels of drought tolerance and nucleotide polymorphism at the CBF4 locus were examined in a world-wide sample of 17 core accessions of Arabidopsis thaliana. The results showed that different accessions exhibited considerable differences in adaptation to drought stress. Compared with Columbia accession, the frequency of nucleotide polymorphism at the CBF4 locus of 25av, 203av and 244av accessions, including single nucleotide polymorphism (SNP) and insertion/deletion (Indel), was high, on average 1 SNP per 35.8 bp and 1 Indel per 143 bp. No significance in all regions of Tajima's D test indicated that the neutral mutation hypothesis could explain the nucleotide polymorphism in this CBF4 gene region. The higher polymorphism was the result of purification selection. Nucleotide polymorphism in the non-coding region was three times higher than in the coding region. This might indicate a recent relaxation of selection pressures on the non-coding region of CBF4 gene. In the coding region of CBF4, SNP frequency was 1 SNP per 96.4 bp and one non-synonymous mutation was detected from 25av, 203av and 244av accessions: the amino acid variation gly↔val at position 205, caused by the nucleotide variation G↔T at position 1034 (corresponding to the nucleotide at position 19 696 of GenBank accession no. AB015478 as 1). Furthermore, four differential SNPs were discovered in haplotype 6 constituted by 203av, one of them located in the 3′ non-coding region (A↔C at position 1106) and the others in the 5′ non-coding region (A↔G, A↔C and G↔A at positions 27, 129 and 171, respectively). The drought tolerance assay indicated that accession 203av was the best at tolerating water deficiency. We propose that haplotype 6 is consistent with its drought tolerance.


2018 ◽  
Vol 5 (1) ◽  
pp. 37-40
Author(s):  
Seri Mirianti Ishar ◽  
Jeyaganesan Pillay a/l Balaraman ◽  
Muhammad Jefri Mohd Yusof ◽  
Khairul Osman ◽  
Lee Loong Chuen

Human DNA consists of nucleus DNA (nDNA) and mitochondrial DNA (mtDNA). Both are valuable in medicine and forensic genetics but in this project, single nucleotide polymorphisms (SNPs) in mtDNA are used to trace the mutation occurred. Mutations in the sequence of alleles can lead to haplogroup variation and also certain diseases. The purpose of this study is to screen of mutations on alleles G709A, G3496T, and A3537G in Malay population of The National University of Malaysia (UKM) students. These SNPs lie in the ND1 (nitrogen dehydrogenase subunit 1) coding region, and the reports state that these three alleles are prone to mutate. From MitoMap Web site, the mutations of these alleles are reported to have potential in causing several diseases with the collaboration of other SNPs mutation. Allele G709A is reported to have an association with hearing loss and Leber Hereditary Optic Neuropathy (LHON) while allele G3496T is associated to LHON only. Allele A3537G is related to diabetes. A total of 100 DNA samples were collected from Malay students of UKM and preserved on FTA card to be purified later. The concentration of the DNA on the purified FTA card was between 10μM to 20μM. An attempt was made by amplifying those three loci from the genomic DNA. The amplified product was detected and separated using 1% gel electrophoresis. Before sequencing, the PCR products were visualized under UV light using gel documentation system. All PCR products were sequenced to detect the mutation on every single position chosen. From the alignment of sequencing results, allele G709A and allele G3496T showed no mutation. Meanwhile four samples from alleles A3537G has the mutation. From the results obtained, it seems that mutations are rare in all selected alleles. It is recommended to increase the sample size and alleles selected in the future to increase the strength of the study. This study also should be applied to other populations in Malaysia such as Chinese and Indian.  


2011 ◽  
Vol 300 (4) ◽  
pp. H1530-H1535 ◽  
Author(s):  
Carol Moreno ◽  
Jan M. Williams ◽  
Limin Lu ◽  
Mingyu Liang ◽  
Jozef Lazar ◽  
...  

Transfer of chromosome 13 from the Brown Norway (BN) rat onto the Dahl salt-sensitive (SS) genetic background attenuates the development of hypertension, but the genes involved remain to be identified. The purpose of the present study was to confirm by telemetry that a congenic strain [SS.BN-(D13Hmgc37-D13Got22)/Mcwi, line 5], carrying a 13.4-Mb segment of BN chromosome 13 from position 32.4 to 45.8 Mb, is protected from the development of hypertension and then to narrow the region of interest by creating and phenotyping 11 additional subcongenic strains. Mean arterial pressure (MAP) rose from 118 ± 1 to 186 ± 5 mmHg in SS rats fed a high-salt diet (8.0% NaCl) for 3 wk. Protein excretion increased from 56 ± 11 to 365 ± 37 mg/day. In contrast, MAP only increased to 152 ± 9 mmHg in the line 5 congenic strain. Six subcongenic strains carrying segments of BN chromosome 13 from 32.4 and 38.2 Mb and from 39.9 to 45.8 Mb were not protected from the development of hypertension. In contrast, MAP was reduced by ∼30 mmHg in five strains, carrying a 1.9-Mb common segment of BN chromosome 13 from 38.5 to 40.4 Mb. Proteinuria was reduced by ∼50% in these strains. Sequencing studies did not identify any nonsynonymous single nucleotide polymorphisms in the coding region of the genes in this region. RT-PCR studies indicated that 4 of the 13 genes in this region were differentially expressed in the kidney of two subcongenic strains that were partially protected from hypertension vs. those that were not. These results narrow the region of interest on chromosome 13 from 13.4 Mb (159 genes) to a 1.9-Mb segment containing only 13 genes, of which 4 are differentially expressed in strains partially protected from the development of hypertension.


2008 ◽  
Vol 5 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Wang Xiao-Bo ◽  
Ma Chuan-Xi ◽  
Si Hong-Qi ◽  
He Xian-Fang

AbstractPolyphenol oxidase (PPO) activity is highly related to the undesirable browning of wheat-based end products. In this study, wheat PPO sequences (mRNA) were searched/BLASTed in the NCBI database and aligned using DNAMAN software. The results showed that wheat PPO genes could be divided into two clusters (I and II) and that three genes (‘i’) of cluster II seemed not to be located on chromosomes 2A and 2D. Ninety-four single nucleotide polymorphisms (SNPs) were detected between two haplotypes of the PPO gene on chromosome 2D. Eighty of these were found in the coding region (coding (c) SNPs) and 36 were non-synonymous cSNPs, which could affect the PPO amino acid sequence. Primers (STS-H) were designed at some non-synonymous cSNPs sites and were used to investigate the correlations between allelic variants and PPO activity of seeds – a total of 130 common wheat varieties were evaluated in 2 years. The results showed that STS-H could amplify a 460 bp DNA fragment in most cultivars with high PPO activity, while no PCR product was detected in most cultivars with low PPO activity. To improve the selection efficiency of a single dominance molecular marker, the multiplex polymerase chain reaction (PCR) system of STS-H and STS01 markers was also studied, based on the complementary between them.


2021 ◽  
Author(s):  
So-Hyeon Bong ◽  
Ganghee Cho ◽  
Dong-Seon Kim ◽  
Sunggil Kim

Abstract Self-incompatibility (SI) responses of radish (Raphanus sativus L.) are determined by two tightly linked genes encoding an S receptor kinase (SRK) and an S-locus cysteine-rich protein/S locus protein 11 (SCR/SP11), respectively. A radish showing an almost self-compatible (SC) phenotype was identified in this study. Inheritance patterns showed that this SC phenotype was dominant over an SI phenotype. In addition, this SC phenotype co-segregated with an S haplotype in an F2 population. This SC radish contained an RsS-26 haplotype in which duplicate SRK-like genes were previously identified. Full-length sequences of two SRK-like genes of 18,133-bp and 6,200-bp in length were obtained from radish with the RsS-26 haplotype (designated as RsSRK-26-1 and RsSRK-26-2, respectively). Duplicate SCR/SP11-like genes were also identified in the radish with the RsS-26 haplotype. Phylogenetic analyses indicated that both duplicate SRK-like and SCR/SP11-like genes were closely related to other known SRK and SCR/SP11 genes, respectively. No critical mutation was found in the coding region of SRK-like or SCR/SP11-like gene. However, a 4,146-bp intact LTR-retrotransposon was identified in the third intron of RsSRK-26-1 of the SC radish. Interestingly, this LTR-retrotransposon was not detected in three other breeding lines containing the same RsS-26 haplotype. Except for this LTR-retrotransposon, only two single nucleotide polymorphisms (SNPs) were identified in intronic regions between normal and mutant RsSRK-26-1 alleles. While normal transcription was observed for radish showing RsSRK-26-1 and SI phenotypes in these three breeding lines, no transcript of RsSRK-26-1 was detected in the SC radish, suggesting that recent transposition of an LTR-retrotransposon in the RsSRK-26-1 gene might be responsible for the SC phenotype of radish.


2021 ◽  
Author(s):  
Asmita Ghosh ◽  
Dattatreya Mukherjee ◽  
Parth Patel ◽  
Debraj Mukhopadhyay

Single nucleotide polymorphism is a genetic substitution of a base pair at a single position of the genome. SNPs are a common phenomenon and influence mRNA expression. Half of the SNPs occur in the non-coding region with 25% being mis-sense mutation and 25% being silent mutations. SNPs belong to the last generation of molecular markers which is identified through SNP mapping. SNPs are extensively studied to distinguish genetic expression and protein synthesis. These genetic differences are a major source of diseases in humans like cancers. One of the most common types of cancer of the brain is the Glioblastoma Multiforme that accounts for more than 80% of the malignant primary brain tumors (PBT). Researchers have found out a potential role of various SNPs in the genome to have a strong relation with Glioma formation and proliferation. Most SNPs are either not discovered, or their biological mechanisms are unknown, making it difficult to link putative associations with disease onset. The given review aims to identify some of the most common SNPs associated with GBM and classify the genetic basis along with future prospects. These SNPs are pioneer in Genome Wide Association studies to help in cancer research and identification of specific genetic alterations liked to GBM. Single Nucleotide Polymorphisms in a gene can be used as genetic biomarkers to aid better understanding of the mechanism of cancer formation, its aetiology, progression and metastatic behaviour.


2021 ◽  
Vol 12 ◽  
Author(s):  
Fabien Degalez ◽  
Frédéric Jehl ◽  
Kévin Muret ◽  
Maria Bernard ◽  
Frédéric Lecerf ◽  
...  

Most single-nucleotide polymorphisms (SNPs) are located in non-coding regions, but the fraction usually studied is harbored in protein-coding regions because potential impacts on proteins are relatively easy to predict by popular tools such as the Variant Effect Predictor. These tools annotate variants independently without considering the potential effect of grouped or haplotypic variations, often called “multi-nucleotide variants” (MNVs). Here, we used a large RNA-seq dataset to survey MNVs, comprising 382 chicken samples originating from 11 populations analyzed in the companion paper in which 9.5M SNPs— including 3.3M SNPs with reliable genotypes—were detected. We focused our study on in-codon MNVs and evaluate their potential mis-annotation. Using GATK HaplotypeCaller read-based phasing results, we identified 2,965 MNVs observed in at least five individuals located in 1,792 genes. We found 41.1% of them showing a novel impact when compared to the effect of their constituent SNPs analyzed separately. The biggest impact variation flux concerns the originally annotated stop-gained consequences, for which around 95% were rescued; this flux is followed by the missense consequences for which 37% were reannotated with a different amino acid. We then present in more depth the rescued stop-gained MNVs and give an illustration in the SLC27A4 gene. As previously shown in human datasets, our results in chicken demonstrate the value of haplotype-aware variant annotation, and the interest to consider MNVs in the coding region, particularly when searching for severe functional consequence such as stop-gained variants.


2019 ◽  
Vol 11 (7) ◽  
pp. 578-585 ◽  
Author(s):  
Thibaut Barnoud ◽  
Joshua L D Parris ◽  
Maureen E Murphy

Abstract The TP53 gene is well known to be the most frequently mutated gene in human cancer. In addition to mutations, there are > 20 different coding region single-nucleotide polymorphisms (SNPs) in the TP53 gene, as well as SNPs in MDM2, the negative regulator of p53. Several of these SNPs are known to alter p53 pathway function. This makes p53 rather unique among cancer-critical genes, e.g. the coding regions of other cancer-critical genes like Ha-Ras, RB, and PI3KCA do not have non-synonymous coding region SNPs that alter their function in cancer. The next frontier in p53 biology will consist of probing which of these coding region SNPs are moderately or strongly pathogenic and whether they influence cancer risk and the efficacy of cancer therapy. The challenge after that will consist of determining whether we can tailor chemotherapy to correct the defects for each of these variants. Here we review the SNPs in TP53 and MDM2 that show the most significant impact on cancer and other diseases. We also propose avenues for how this information can be used to better inform personalized medicine approaches to cancer and other diseases.


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