• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2005년도 BIOINFO 2005
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• pp.63-68
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• 2005

Transcription factors regulate gene expression by binding to gene upstream region. Each transcription factor has the specific binding site in promoter region. So the analysis of gene upstream sequence is necessary for understanding regulatory mechanism of genes, under a plausible idea that assumption that DNA sequence motif profiles are closely related to gene expression behaviors of the corresponding genes. Here, we present an effective approach to the analysis of the relation between gene expression profiles and gene upstream sequences on the basis of kernel canonical correlation analysis (kernel CCA). Kernel CCA is a useful method for finding relationships underlying between two different data sets. In the application to a yeast cell cycle data set, it is shown that gene upstream sequence profile is closely related to gene expression patterns in terms of canonical correlation scores. By the further analysis of the contributing values or weights of sequence motifs in the construction of a pair of sequence motif profiles and expression profiles, we show that the proposed method can identify significant DNA sequence motifs involved with some specific gene expression patterns, including some well known motifs and those putative, in the process of the yeast cell cycle.

• 한국동물위생학회지
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• 제37권3호
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• pp.157-164
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• 2014

Clostridium chauvoei is the etiologic agent of blackleg, a high mortality rated disease infection mainly cattle. In the present study, the partial sequences of 16S rRNA and flagellin gene of C. chauvoei isolated in Jeonbuk, Korea were determined and compared with those of reference strain. Oligonucleotide primers were designed to amplify a 811 bp fragment of 16S rRNA gene and 1229 bp fragment of flagellin gene. Sequencing analysis of 16S rRNA gene showed high homology to the reference strains ranging 82.3% to 100%, while flagellin gene were different from published foreign clostridia, showing 98.7% to 72.0% nucleotide sequence homology. Phylogenetic analysis based on 16S rRNA gene revealed the close phylogenetic relationship of C. chauvoei and C. septicum in cluster I, which includes C. carnis, C. tertium, C. quinii, C. celatum, C. perfringens, C. absonum, C. botulinum B. Phylogentic analysis also revealed that flagellin gene formed a single cluster with C. chauvoei, C. septicum, C. novyi A, C. novyi B, C. tyrobutylicum, C. acetobutylicum. The genetic informations obtained from this study could be useful for the molecular study of C. chauvoei.

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.2031-2037
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• 2012

Background: Analysis of gene-gene and gene-environment interactions for complex multifactorial human disease faces challenges regarding statistical methodology. One major difficulty is partly due to the limitations of parametric-statistical methods for detection of gene effects that are dependent solely or partially on interactions with other genes or environmental exposures. Based on our previous case-control study in Chongqing of China, we have found increased risk of colorectal cancer exists in individuals carrying a novel homozygous TT at locus rs1329149 and known homozygous AA at locus rs671. Methods: In this study, we proposed statistical method-crossover analysis in combination with logistic regression model, to further analyze our data and focus on assessing gene-environmental interactions for colorectal cancer. Results: The results of the crossover analysis showed that there are possible multiplicative interactions between loci rs671 and rs1329149 with alcohol consumption. Multifactorial logistic regression analysis also validated that loci rs671 and rs1329149 both exhibited a multiplicative interaction with alcohol consumption. Moreover, we also found additive interactions between any pair of two factors (among the four risk factors: gene loci rs671, rs1329149, age and alcohol consumption) through the crossover analysis, which was not evident on logistic regression. Conclusions: In conclusion, the method based on crossover analysis-logistic regression is successful in assessing additive and multiplicative gene-environment interactions, and in revealing synergistic effects of gene loci rs671 and rs1329149 with alcohol consumption in the pathogenesis and development of colorectal cancer.

• Genomics & Informatics
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• 제21권4호
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• pp.45.1-45.11
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• 2023

Nonalcoholic fatty liver disease (NAFLD) is a common type of chronic liver disease, with severity levels ranging from nonalcoholic fatty liver to nonalcoholic steatohepatitis (NASH). The extent of liver fibrosis indicates the severity of NASH and the risk of liver cancer. However, the mechanism underlying NASH development, which is important for early screening and intervention, remains unclear. Weighted gene co-expression network analysis (WGCNA) is a useful method for identifying hub genes and screening specific targets for diseases. In this study, we utilized an mRNA dataset of the liver tissues of patients with NASH and conducted WGCNA for various stages of liver fibrosis. Subsequently, we employed two additional mRNA datasets for validation purposes. Gene set enrichment analysis (GSEA) was conducted to analyze gene function enrichment. Through WGCNA and subsequent analyses, complemented by validation using two additional datasets, we identified five genes (BICC1, C7, EFEMP1, LUM, and STMN2) as hub genes. GSEA analysis indicated that gene sets associated with liver metabolism and cholesterol homeostasis were uniformly downregulated. BICC1, C7, EFEMP1, LUM, and STMN2 were identified as hub genes of NASH, and were all related to liver metabolism, NAFLD, NASH, and related diseases. These hub genes might serve as potential targets for the early screening and treatment of NASH.

• Toxicological Research
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• 제22권4호
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• pp.323-328
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• 2006

Global gene expression profile was analyzed by microarray analysis of rat liver RNA after acute acetaminophen (APAP) administration. A single dose of 1g/kg body weight of APAP was given orally, and the liver samples were obtained after 24, 48 h, and 2 weeks. Histopathologic and biochemical studies enabled the classification of the APAP effect into injury (24 and 48 h) and regeneration (2 weeks) stages. The expression levels of 4900 clones on a custom rat gene microarray were analyzed and 484 clones were differentially expressed with more than a 1.625-fold difference(which equals 0.7 in log2 scale) at one or more time points. Two hundred ninety seven clones were classified as injury-specific clones, while 149 clones as regeneration-specific ones. Characteristic gene expression profiles could be associated with APAP-induced gene expression changes in lipid metabolism, stress response, and protein metabolism. We established a global gene expression profile utilizing microarray analysis in rat liver upon acute APAP administration with a full chronological profile that not only covers injury stage but also later point of regeneration stage.

• 응용통계연구
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• 제25권2호
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• pp.269-277
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• 2012

마이크로어레이 분석은 특이 발현하는 개별적인 유전자보다 유전자 온톨로지(Gene Ontology)와 같이 기능적 분류나 생물학적 경로(pathway)와 관련된 유전자군을 찾아내는 것이 그 해석의 용이성 때문에 최근 더욱 많은 연구가 진행되고 있다. 약물 처리에 의한 생물학적 반응을 연구할 때, 한 유전자군에 속하는 유전자들 각각의 특이 발현 여부의 유의성을 나타내는 $p$-value들을 취합하여 그 유전자군의 유의성을 결정하는 통계 검증 방법을 본 논문에서 소개하였다. 본 논문에 제시된 유전자군 분석(Gene group analysis) 방법은 Fisher's exact test나 permutation test와 같은 기존의 대표적인 방법들보다 더 정확하고 적용범위가 넓음을 실재 생물학 실험 자료의 분석을 통해 보였다. 제시된 유전자군 분석 방법은 SAS 프로그램으로 구현되었고 저자의 홈페이지(http://cafe.daum.net/go.analysis)에서 내려 받아 사용할 수 있다.

• 응용통계연구
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• 제24권2호
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• pp.315-321
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• 2011

Gene expression microarray data often include multiple missing values. Most gene expression analysis (including gene clustering analysis); however, require a complete data matric as an input. In ordinary clustering methods, just a single missing value makes one abandon the whole data of a gene even if the rest of data for that gene was intact. The quality of analysis may decrease seriously as the missing rate is increased. In the opposite aspect, the imputation of missing value may result in an artifact that reduces the reliability of the analysis. To clarify this contradiction in microarray clustering analysis, this paper compared the accuracy of clustering with and without imputation over several microarray data having different missing rates. This paper also tested the clustering efficiency of several imputation methods including our propose algorithm. The results showed it is worthwhile to check the clustering result in this alternative way without any imputed data for the imperfect microarray data.

• 한국식물병리학회지
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• 제11권1호
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• pp.87-90
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• 1995

Complementary DNA of the movement protein (MP) gene of tobacco mosaic virus Korean pepper strain (TMV-KP) was synthesized from purified TMV-KP RNA by using the reverse transcription and polymerase chain reaction (PCR) system. The synthesized double stranded cDNA was cloned into the plasmid pUC9 and transformed into Escherichia coli JM110. The movement protein gene of TMV-KP of the selected clones was subjected to sequence analysis by Sanger's dideoxy chain termination method. The complete sequence of viral MP gene from TMV-KP strain was 807 nucleotides long. The nucleotide of MP gene from TMV-KP has thirteen and two nucleotide differences from TMV vulgarae (TMV-OM) and Korean (TMV-K) strains, respectively. Thus, the nucleotide sequence of TMV-KP MP gene showed higher homology of 99% with that of TMV-K MP gene.

• Communications for Statistical Applications and Methods
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• 제16권3호
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• pp.397-408
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• 2009

마이크로어레이 기술은 수만 개 유전자의 발현 패턴을 동시에 관찰하는 것을 가능하게 하였고, 이들을 하나씩 검정하여 찾아낸 특이발현 현상을 보이는 유전자를 중심으로 질병의 진단, 치료법 정립과 신약 개발을 위한 기본 정보를 확립하였다. 그러나 개별 유전자분석의 여러 문제점이 발견되면서 유전자들을 생물학적 대사경로나 염색체 위치가 같은 것끼리 묶은 집단을 분석하여 질병의 발생이나 생존에 영향을 미치는 집단을 찾는 방법이 제시되었다. 이러한 유전자 집단의 유의성에 대한 연구는 2002년에 MIT에서 비롯되어 GSEA, SAM-GS와 중심극한 정리의 개념을 이용한 모수적 방법인 PAGE 등이 사용되고 있다. 본 논문에서는 이들 통계량의 구조적 한계를 극복하고 계산이 간단한 새로운 모수적 방법을 제안하고 자료 분석을 통하여 효율성을 보였다.

• Genomics & Informatics
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• 제18권4호
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• pp.38.1-38.9
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• 2020

Chronotype is an important moderator of psychiatric illnesses, which seems to be controlled in some part by genetic factors. Clock genes are the most relevant genes for chronotype. In addition to the roles of individual genes, gene-gene interactions of clock genes substantially contribute to chronotype. We investigated genetic associations and gene-gene interactions of the clock genes BHLHB2, CLOCK, CSNK1E, NR1D1, PER1, PER2, PER3, and TIMELESS for chronotype in 1,293 healthy Korean individuals. Regression analysis was conducted to find associations between single nucleotide polymorphism (SNP) and chronotype. For gene-gene interaction analyses, the quantitative multifactor dimensionality reduction (QMDR) method, a nonparametric model-free method for quantitative phenotypes, were performed. No individual SNP or haplotype showed a significant association with chronotype by both regression analysis and single-locus model of QMDR. QMDR analysis identified NR1D1 rs2314339 and TIMELESS rs4630333 as the best SNP pairs among two-locus interaction models associated with chronotype (cross-validation consistency [CVC] = 8/10, p = 0.041). For the three-locus interaction model, the SNP combination of NR1D1 rs2314339, TIMELESS rs4630333, and PER3 rs228669 showed the best results (CVC = 4/10, p < 0.001). However, because the mean differences between genotype combinations were minor, the clinical roles of clock gene interactions are unlikely to be critical.