• BMB Reports
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• v.42 no.6
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• pp.315-323
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• 2009

In order to elucidate ultimate biological function of the genome, the model animal system carrying mutations is indispensable. Recently, large-scale mutagenesis projects have been launched in various species. Especially, the mouse is considered to be an ideal model to human because it is a mammalian species accompanied with well-established genetic as well as embryonic technologies. In 1990', large-scale mouse mutagenesis projects firstly initiated with a potent chemical mutagen, N-ethyl-N-nitrosourea (ENU) by the phenotype-driven approach or forward genetics. The knockout mouse mutagenesis projects with trapping/conditional mutagenesis have then followed as Phase II since 2006 by the gene-driven approach or reverse genetics. Recently, the next-generation gene targeting system has also become available to the research community, which allows us to establish and analyze mutant mice carrying an allelic series of base substitutions in target genes as another reverse genetics. Overall trends in the large-scale mouse mutagenesis will be reviewed in this article particularly focusing on the new advancement of the next-generation gene targeting system. The drastic expansion of the mutant mouse resources altogether will enhance the systematic understanding of the life. The construction of the mutant mouse resources developed by the forward and reverse genetic mutagenesis is just the beginning of the annotation of mammalian genome. They provide basic infrastructure to understand the molecular mechanism of the gene and genome and will contribute to not only basic researches but also applied sciences such as human disease modelling, genomic medicine and personalized medicine.

• BMB Reports
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• v.51 no.10
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• pp.481-483
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• 2018

Glioblastoma (GBM) is the most common and aggressive form of human adult brain malignancy. The identification of the cell of origin harboring cancer-driver mutations is the fundamental issue for understanding the nature of GBM and developing the effective therapeutic target. It has been a long-term hypothesis that neural stem cells in the subventricular zone (SVZ) might be the origin-of-cells in human glioblastoma since they are known to have life-long proliferative activity and acquire somatic mutations. However, the cell of origin for GBM remains controversial due to lack of direct evidence thereof in human GBM. Our recent study using various sequencing techniques in triple matched samples such as tumor-free SVZ, tumor, and normal tissues from human patients identified the clonal relationship of driver mutations between GBM and tumor-free SVZ harboring neural stem cells (NSCs). Tumor-free SVZ tissue away from the tumor contained low-level GBM driver mutations (as low as 1% allelic frequency) that were found in the dominant clones in its matching tumors. Moreover, via single-cell sequencing and microdissection, it was discovered that astrocyte-like NSCs accumulating driver mutations evolved into GBM with clonal expansion. Furthermore, mutagenesis of cancer-driving genes of NSCs in mice leads to migration of mutant cells from SVZ to distant brain and development of high-grade glioma through the aberrant growth of oligodendrocyte precursor lineage. Altogether, the present study provides the first direct evidence that NSCs in human SVZ is the cell of origin that develops the driver mutations of GBM.

• Korean journal of applied entomology
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• v.20 no.1 s.46
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• pp.15-20
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• 1981

To analyze the inheritance of emergence rate of brown plant hopper (Nilaparvata lugens) biotypes, six crosses among biotype 1, biotype 2 induced by rearing on Mudgo and biotype 3 these on ASD 7, were made. Each generation $(P_1,\;P_2,\;F_l\; F_2,\;BC_1,\;BC_2)$ of each cross was fed on the rice seedlings of Mudgo and ASD 7 varieties. The emergence rate of biotpe 2 on Mudgo was controlled by the one incomplete dominant gene in $biotype\;l{\times}biotype$ 2 coross, however, that of biotype 3 on ASD 7 was controlled by one incomplete recessive gene in $biotype\;l{\times}biotype$ 3 cross. The genes involved in biotype 2 and biotype 3 were not identical, however, their allelic relations are not clear.

• 한국균학회소식:학술대회논문집
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• 2018.05a
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• pp.37-37
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• 2018

Mating type of Lentinula edodes is determined by two unlinked genetic loci, A and B. To better understand mating behavior of L. edodes, we investigated variations in mating type genes in129 dikaryotic strains collected from East Asia. Through sequence analysis of A locus, we discovered that hypervariable region spanning N-term of HD2-intergenic region-N-term of HD1 could represent A mating type. Mating and hypervariable region analyses revealed 70 unique A mating types: 27 from 98 cultivated strains, 53 from 31 wild strains, and 10 commonly found. It was also revealed that only a few A mating type alleles such as A1, A4, A5, and A7 were prevalent in cultivated strains. Contrarily, A mating type in wild strains was highly diverse: 23 unique A alleles were discovered in small mountainous area in Korean peninsula, suggesting rapid evolution of A mating type in nature. The B locus was assessed by allelic variations in pheromone (PHB) and pheromone receptor (RCB) pairs which constituted subloci Ba and Bb. Sequence analyses and mating assay revealed 5 alleles of RCB1 with 9 associated PHBs in Ba sublocus and 3 alleles of RCB2 with 5 associated PHBs in Bb sublocus. Each RCB was primarily associated with two PHBs. Each PHB-RCB pair was always discovered as a distinct unit. This allowed us to propose 15 B mating types via combinations of five Ba and three Bb subloci. Further investigation on 129 strains confirmed that the B locus, unlike the A locus, was indeed restricted to 15 mating types. Thus, the total number of mating types became 1,050 in L. edodes through a combination of 70 A and 15 B. This number will further increase because of rapid diversification of A mating type. Our findings provide a comprehensive and practical knowledge on mating behaviors of L. edodes.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.6-11
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• 1990

Analysis of genetic structure in Kimpo natural population of Drosophila was carried out by utilizing the deleterious gene on the second chromosome of Drosophila melanogaster. Male flies tested were continuously collected for eight years; in late September 1974 and 1981-1987. The frequency of deleterious gene (lethal plus semilethal) ranged from 27.02% in 1983 to 41.48% in 1987, and the values estimated from the eight years samples are highly signihcent from each other with a homogenety test (X$^2$=52.0157, d.f.=28, P<0.005). Allelic rates ranged from 1.30% in 1981 to 5.03% in 1974. And the effective population size by using the rate of allelism was estimated average at 3, 300 pairs. Elimination rate by homozygous of lethal gene ranged from 0.0004 in 1984 to 0.0019 in 1974, and that is for smaller than mutation rate(0.005) at second chromosome. We suppose that stable frequency (about 20%) lethal genes of D. melanogaster in Kimpo natual population are maintained by invade of P-type mutator factor (P element) versus eliminated in heterozygous and homozygous condition of lethal gene.

• Korean Journal of Veterinary Research
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• v.53 no.2
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• pp.95-101
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• 2013

The study was carried out to evaluate and compare the immune responses in mice experimentally infected with either wild-type or isogenic mutants of Salmonella enterica serovars Enteritidis (SE), Salmonella Typhimurium (ST) and Gallinarum (SG). The mutant strains were constructed by allelic replacement of some virulence-associated genes in the wild-type strains. Seven-week-old female BALB/c mice were orally or intraperitoneally inoculated by injecting bacterial suspension. To evaluate the immune responses, enzyme-linked immunosorbent assay (ELISA) and enzyme-linked immunospot (ELISPOT) assay were conducted with serum and fecal samples. As a result, the mice group infected orally with the SE mutant strain showed the highest level of specific IgA-secreting splenocytes, compared to the other groups. The peritoneally injected groups showed the greater levels of IgG1 than the orally injected groups, which was in a good agreement with the previous studies. In addition, the mutant infected groups had the similar secretion levels of antibodies with the wild-type infected groups. These results demonstrated that the SE mutant strain elicited humoral immune response as much as wild-type, implying that it can be useful as a delivery vehicle as well as a candidate of a live attenuated vaccine.

• The Journal of Korean Medicine
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• v.26 no.1 s.61
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• pp.85-92
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• 2005

Objective: A number of candidate genes have been in implicated in the pathogenesis of obesity in humans. Tumor necrosis factor-alpha $(TNF-{\alpha})$ is expressed primarily in adipocytes, and elevated levels of this cytokine have been linked to obesity and insulin resistance. Recently, the A allele of a polymorphism at position 308 in the promoter region of $TNF-{\alpha}$ (G-308A) has been shown to increase transcription of the gene in adipocytes. Therefore, we designed this study to test whether obese and non-obese subjects differ in $TNF-{\alpha}$ genotype distribution, and how the genotypes affect anthropometric parameters, including degrees of body mass index (BMI). Methods : The study included 153 obese but otherwise healthy women ($BMI{\geq}kg/m^2$, range 25-54.7, age range 15-40 years) and 82 non-obese healthy women ($BMI, age range 15-40 years). Total fat mass and percent body fat were determined by dual-energy X-ray absorptiometry. Genomic DNA was extracted and used for Ncol restriction fragment length polymorphism (RFLP) based genotyping of $TNF-{\alpha}$. Results: No differences were observed for allelic and genotype frequencies between the obese ($BMI{\geq}25$) and non-obese women. Also, no association of TNF-(l polymorphism was observed with body mass index (BMI) for genotype in obese women. In addition, age, pertent body fat, BMI, and cholesterol levels did not differ by $TNF-{\alpha}$ genotype. However, waist-to­hip ratio (WHR) was significantly lower in subjects with $TNF-{\alpha}$ GA or AA genotype (0.94 0.07 vs. 0.920.03, P<0.005). Conclusion: These results suggest that $TNF-{\alpha}$ promoter polymorphism at position-308 is not a significant factor for BMI, but affects the WHR in obese healthy women from Koreans.

• YAKHAK HOEJI
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• v.54 no.1
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• pp.49-54
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• 2010

SLC6A19 which reported as a neurotransmitter was composed of seven minisatellites. In previous our study, the minisatellites variants of SLC6A19-MS7 showed the susceptibility for hypertension. When this minisatellte sequences were analyzed using the bioinformatic tool, USF1 (upstream transcription factor 1) was found in this region as a putative transcription factor binding site. USF1 is binding with E-boxes which has a consensus sequence of CACGTG. USF1 is a ubiquitously expressed transcription factor and involved in the transcriptional control of many genes including the molecular pathogenesis of cardiovascular disease. Thus, we investigated that the putative functional relationship between the minisatellites variants and susceptibility for myocardial infarction. A case-control study was performed that compared genomic DNA from 400 controls and 225 cases with myocardial infarction. There were no significant differences observed in the overall allelic distribution of minisatellites between controls and cases, which indicates that this polymorphism is not responsible for myocardial infarction susceptibility. Hence, we analyzed the five different minisatellites alleles from this study and characterized 14 different repeats units (Unit1~Unit14). Then, we evaluated the DNA composition, phylogenic tree, and pairwise distances of its repeats. The variability of each repeats differed from 2.33% to 16%. The phylogenic trees for the four SLC6A19-MS7 minisatellites exhibited very different shapes in their braches and distances, and present most common 8 repeats allele was the longest 14 repeats allele. Therefore, this result may help to understand for the evolutional level of the length of minisatellites.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.325-334
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• 2007

Recently, quorum sensing has been implicated as an important global regulator controlling the production of numerous virulence factors such as capsular polysaccharides in bacterial pathogens. The nucleotide and deduced amino acid sequences of smcR, a homolog of V. harveyi luxR identified from V. vulnificus ATCC29307, were analyzed. The amino acid sequence of SmcR from V. vulnificus was 72 to 92% similar to those of LuxR homologs from Vibrio spp. Functions of SmcR were assessed by the construction of an isogenic mutant, whose smcR gene was inactivated by allelic exchanges, and by evaluating its phenotype changes in vitro and in mice. The disruption of smcR resulted in a significant alteration in biofilm formation, in type of colony morphology, and in motility. When compared with the wild-type, the smcR mutant exhibited reduced survival under adverse conditions, such as acidic pH and hyperosmotic stress. The smcR mutant exhibited decreased cytotoxic activity toward INT 407 cells in vitro. Furthermore, the intraperitoneal $LD_{50}$ of the smcR mutant was approximately $10^2$ times higher than that of parental wild-type. Therefore, it appears that SmcR is a novel global regulator, controlling numerous genes contributing to the pathogenesis as well as survival of V. vulnificus.

• Journal of agriculture & life science
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• v.46 no.6
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• pp.1-8
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• 2012

This study was carried out to determine the genic values of taste of Korean hot pepper (Capsicum annuum L.) in practical genetic resources of using to breed them. The two breeding materials of pepper, '#1803' ($P_1$) of prefer tastes and '#1532' ($P_2$) of ordinary taste, and their $F_1$, $F_2$ generations were used in this study. By using partitioning method it was possible to estimate, from the $F_2$ generation, the number of effective factor pairs differentiating the two parents. There were found to be differentiated by two effective factor pairs. In practical genetic resource of using to breed the Korean hot pepper, the heritance of pepper tastes showed that the $F_1$ was better than excellent parent by reason of over dominant, but some $F_2$ was better than both parent by transgressive segregation. As the result, the magnitude of genic effects of A-a gene in pepper tastes was 0.36, and B-b gene was 0.64. The tastes of Korean hot pepper showed a complex inheritance by interaction effect on the two non-allelic factors of 0.94 and secondary effect of 2.86 at the most.