• International Journal of Industrial Entomology and Biomaterials
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• v.15 no.2
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• pp.93-100
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• 2007

After a serial study on the therapeutic efficacy of the powdery silkworm for diabetics was positively resulted in, many powdery silkworm products were on the market in Korea. Up to now, however, no causal method is available to discriminate the strain of silkworms that is a major ingredient for manufacturing powdery silkworm, even though the quality of the powdery silkworm differs greatly by source and origin of strains. We previously were successful in identifying 25 silkworm strains kept in Korea using nine intronic sequences. In this study, we tested the utility of the nine intronic sequences to distinguish the most widely reared silkworm strains originated from Korea and China. Two intron regions, PTTH Intron3 and PTTH Intron3, showed a substantial sequence divergence (mean sequence divergence of 3.13% in PTTH Intron3 and 4.99% in PTTH Intron3). These two intronic sequences provided no identical sequences among the seven strains tested. Thus, these sequences each along can be used to discriminate the seven strains tested in this study. Furthermore, other intron regions, except for VDP Intron4 allowed us to discriminate $2{\sim}4$ strains by strain-specific unique insertion/deletion or substitution.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.23-27
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• 2008

Self-splicing group I introns in tRNA anticodon loops have been found in diverse groups of bacteria. In this work, we identified $tRNA^{fMet}$ group I introns in six strains of marine Synechococcus elongatus. Introns with sizes around 280 bp were consistently obtained in all the strains tested. In a phylogenetic analysis using the nucleotide sequence determined in this study with other cyanobacterial $tRNA^{fMet}$ and $tRNA^{Leu}$ intron sequences, the Synechococcus sequence was grouped together with the sequences from other unicellular cyanobacterial strains. Interestingly, the phylogenetic tree inferred from the intronic sequences clearly separates the different tRNA introns, suggesting that each family has its own evolutionary history.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.9 no.1
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• pp.1-7
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• 2005

The genomes of organism are being published in an enormous speed. The genomes has a lot of intronic regions, and repeats constitute a substantial part of that. Repeats playa crucial role in DNA finger-printing, and detecting certain genomic diseases, such as Huntington disease, which has a high number of CAG repeats. Also, they throw important clues about the evolutionary history. Repeats are in two types, Tandem Repeats and Interspersed Repeats. In this paper we address ourselves to the problem of detecting Primary Tandem Repeats, which are tandem repeats that are not contained in any tandem repeats. We show that our algorithm takes O(n log n) time, where n is the length of genome.

• Journal of Animal Science and Technology
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• v.49 no.6
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• pp.719-728
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• 2007

The cysteine and glycine rich protein 3 (CSRP3), apolipoprotein B mRNA editing enzyme catalytic polypeptide‐like 2(APOBEC2) and caveolin (CAV) gene family(CAV1, CAV2, CAV3) have been reported to play important roles for carcass and meat quality traits in pig, mouse, human and cattle. As an initial step, we investigated SNPs in these 5 genes among eight different cattle breeds. Eighteen primer pairs were designed from bovine sequence data of NCBI database to amplify the partial gene fragments. Sequencing results revealed 9 SNPs in the coding regions of three caveolin genes, 1 SNP in CSRP3 and 3 SNPs in APOBEC2 gene. All the identified SNPs were confirmed by PCR-RFLP. Also, 9 more intronic SNPs were detected in these genes. However, all identified mutations in the coding region do not change amino acid sequence. Allelic distributions were significantly different for 5 SNPs in CAV2, CAV3, CSRP3 and APOBEC2 genes among the eight different breeds. These results gave some clues about the polymorphisms of these genes among the cattle breeds and will be useful for further searches for identifying association between these SNPs and meat quality traits in cattle.

• Genomics & Informatics
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• v.5 no.2
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• pp.68-76
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• 2007

Due to the increasing interest in SNPs and mutational hot spots for disease traits, it is becoming more important to define and understand the relationship between SNPs and their flanking sequences. To study the effects of flanking sequences on SNPs, statistical approaches are necessary to assess bias in SNP data. In this study we mainly applied Markov chains for SNP sequences, particularly those located in intronic regions, and for analysis of in-del data. All of the pertaining sequences showed a significant tendency to generate particular SNP types. Most sequences flanking SNPs had lower complexities than average sequences, and some of them were associated with microsatellites. Moreover, many Alu repeats were found in the flanking sequences. We observed an elevated frequency of single-base-pair repeat-like sequences, mirror repeats, and palindromes in the SNP flanking sequence data. Alu repeats are hypothesized to be associated with C-to-T transition mutations or A-to-I RNA editing. In particular, the in-del data revealed an association between particular changes such as palindromes or mirror repeats. Results indicate that the mechanism of induction of in-del transitions is probably very different from that which is responsible for other SNPs. From a statistical perspective, frequent DNA lesions in some regions probably have effects on the occurrence of SNPs.

• Molecules and Cells
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• v.26 no.6
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• pp.554-557
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• 2008

Double-stranded RNA (dsRNA) induces gene silencing in a sequence-specific manner by a process known as RNA interference (RNAi). The RNA-induced silencing complex (RISC) is a multi-subunit ribonucleoprotein complex that plays a key role in RNAi. VIG (Vasa intronic gene) has been identified as a component of Drosophila RISC; however, the role VIG plays in regulating RNAi is poorly understood. Here, we examined the spatial and temporal expression patterns of VIG-1, the C. elegans ortholog of Drosophila VIG, using a vig-1::gfp fusion construct. This construct contains the 908-bp region immediately upstream of vig-1 gene translation initiation site. Analysis by confocal microscopy demonstrated GFP-VIG-1 expression in a number of tissues including the pharynx, body wall muscle, hypodermis, intestine, reproductive system, and nervous system at the larval and adult stages. Furthermore, western blot analysis showed that VIG-1 is present in each developmental stage examined. To investigate regulatory sequences for vig-1 gene expression, we generated constructs containing deletions in the upstream region. It was determined that the GFP expression pattern of a deletion construct (${\Delta}-908$ to -597) was generally similar to that of the non-deletion construct. In contrast, removal of a larger segment (${\Delta}-908$ to -191) resulted in the loss of GFP expression in most cell types. Collectively, these results indicate that the 406-bp upstream region (-596 to -191) contains essential regulatory sequences required for VIG-1 expression.

• Molecules and Cells
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• v.39 no.12
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• pp.888-897
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• 2016

Stable expression of Foxp3 is ensured by demethylation of CpG motifs in the Foxp3 intronic element, the conserved non-coding sequence 2 (CNS2), which persists throughout the lifespan of regulatory T cells (Tregs). However, little is known about the mechanisms on how CNS2 demethylation is sustained. In this study, we found that Ten-Eleven-Translocation (Tet) DNA dioxygenase protects the CpG motifs of CNS2 from re-methylation by DNA methyltransferases (Dnmts) and prevents Tregs from losing Foxp3 expression under inflammatory conditions. Upon stimulation of Tregs by interleukin-6 (IL6), Dnmt1 was recruited to CNS2 and induced methylation, which was inhibited by Tet2 recruited by IL2. Tet2 prevented CNS2 re-methylation by not only the occupancy of the CNS2 locus but also by its enzymatic activity. These results show that the CNS2 methylation status is dynamically regulated by a balance between Tets and Dnmts which influences the expression of Foxp3 in Tregs.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.11
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• pp.4589-4592
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• 2015

Background: Missense and frame-shift mutations within the dimer forming domain of the caspase 8 gene have been identified in several cancers. However, the genetic status of this region in precancerous lesions, like oral submucous fibrosis (OSMF), and well differentiated oral squamous cell carcinomas (OSCCs) in patients from southern region of India is not known, and hence the present study was designed to address this issue. Materials and Methods: Genomic DNA isolated from biopsy tissues of thirty one oral submucous fibrosis and twenty five OSCC samples were subjected to PCR amplification with intronic primers flanking exon 7 of the caspase 8 gene. The PCR amplicons were subsequently subjected to direct sequencing to elucidate the status of mutation. Results: Sequence analysis identified a frame-shift and a novel missense mutation in two out of twenty five OSCC samples. The frame-shift mutation was due to a two base pair deletion (c.1225_1226delTG), while the missense mutation was due to substitution of wild type cysteine residue with phenylalanine at codon 426 (C426F). The missense mutation, however, was found to be heterozygous as the wild type C426C codon was also present. None of the OSMF samples carried mutations. Conclusions: The identification of mutations in OSCC lesions but not OSMF suggests that dimer forming domain mutations in caspase 8 may be limited to malignant lesions. The absence of mutations in OSMF also suggests that the samples analyzed in the present study may not have acquired transforming potential. To the best of our knowledge this is the first study to have explored and identified frame-shift and novel missense mutations in OSCC tissue samples.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.7
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• pp.4279-4282
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• 2013

Background: The activation and inactivation of receptor tyrosine kinases are tightly regulated to ensure faithful replication of cells. After having transduced extracellular growth activating signals, activated EGFR is subjected to downregulation either by clathrin mediated endocytosis or c-Cbl mediated proteasome degradation depending on the ligand concentration. c-Cbl is an ubiquitin ligase which requires a phosphorylated tyrosine residue at position 1045 in the cytoplasmic domain of EGFR to interact and add ubiquitin molecules. While activating mutations in exons 19 and 21 have been associated with the development of several cancers, the status of mutations at tyrosine 1045 coding exon 27 of EGFR remain to be investigated. Consistently, defective phosphorylation at 1045 has been associated with sustained phosphorylation of EGFR in non-small lung carcinomas. Hence in the present study we investigated the genetic status of the tyrosine 1045 coding site within exon 27 of EGFR gene to explore for possible occurrence of mutations in this region, especially since no studies have addressed this issue so far. Materials and Methods: Tumor chromosomal DNA isolated from thirty five surgically excised oral squamous cell carcinoma tissues was subjected to PCR amplification with intronic primers flanking the tyrosine 1045 coding exon 27 of EGFR gene. The PCR amplicons were subsequently subjected to direct sequencing to elucidate the mutation status. Results: Sequence analysis identified no mutations in the tyrosine 1045 codon of EGFR in any of the thirty five samples that were analyzed. Conclusions: The lack of identification of mutation in the tyrosine 1045 codon of EGFR suggests that mutations in this region may be relatively rare in oral squamous cell carcinomas. To the best of our knowledge, this study is the first to have explored the genetic status of exon 27 of EGFR in oral squamous cell carcinoma tissue samples.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.910-913
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• 2004

Insulin-like growth factor binding protein-3 (IGFBP-3) gene is a structural gene associated with the growth and development of the animals. The present investigation was carried out to unravel nucleotide sequence and polymerase chain reactionrestriction fragment polymorphism (PCR-RFLP) of IGFBP-3 gene in buffalo. Genomic DNA was isolated from a total of 157 animals belonging to Murrah, Surti, Jaffarabadi and Nagpuri breeds of Indian riverine buffalo. A 655 bp of IGFBP-3 gene was amplified in all the breeds and amplicons were digested with Hae III, Taq I and Msp I restriction enzymes. On digestion with Hae III yielded single restriction pattern of 8 fragments of sizes 201, 165, 154, 56, 36, 19, 16 and 8 bp in all the animals studied. Similarly Taq I and Msp I also revealed single restriction pattern yielding fragments of sizes 240 and 415 bp and 145 and 510 bp, respectively. This shows nonpolymorphic nature of restriction sites in buffalo. Nucleotide sequencing of 587 bp of IGFBP-3 gene in Murrah buffalo was done and submitted to the GenBank (Accession No. AY304829). Nucleotide sequencing revealed an addition of 4 bases in the intronic region as compared to cattle.