• Journal of Life Science
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• v.14 no.6 s.67
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• pp.1023-1027
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• 2004

The RAD3 gene of Saccharomyces cerevisiae is essential for the incision step of UV-induced excision repair. An yeast RAD3 gene has been previously isolated by functional complementation. In order to identify the RAD3 homologous gene from fungus Coprinus cinereus, we have constructed cosmid libraries from electrophoretically separated chromosomes of the C. cinereus. The 13 C. cinereus chromosomes were resolved by pulse-field gel electrophoresis, hybridized with S. cerevisiae RAD3 DNA, and then isolated RAD3 homologous DNA from C. cinereus chromosome. The RAD3 homolog DNA was contained in 3.2 kb DNA fragment. Here, we report the results of characterization of a fungus C. cinereus homolog to the yeast RAD3 gene. Southern blot analysis confirmed that the C. cinereus chromosome contains the RAD3 homolog gene and this gene exists as a single copy in C. cinereus genome. When total RNA isolated from the C. cinereus cells were hybridized with the 3.4 kb PvuII DNA fragment of the S. cerevisiae RAD3 gene, transcripts size of 2.8 kb were detected. In order to investigate whether the increase of the amount of transcripts by DNA damaging agent, transcript levels were examined after treating agents to the cells. The level of transcripts were not increased by untraviolet light (UV). This result indicated that the RAD3 homologous gene is not UV inducible gene. Gene deletion experiments indicate that the HRD3 gene is essential for viability of the cells and DNA repair function. These observations suggest an evolutionary conservation of other protein components with which HRD3 interacts in mediating its DNA repair and viability functions.

• Parasites, Hosts and Diseases
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• v.25 no.2
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• pp.154-158
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• 1987

As a series of systematic classification of paramphistomes, the worms in the rumen and reticulum were collected on 214 Korean cattle slaughtered at Jeonju abattoir from January, 1986 to April, 1987 and were classified by means of morphology. Afterwards, the karyotype of Paramphistomum cervi(Zeder, 1790) was detected by means of modified air.drying method from germ cells of the worms. The results were summarized as follows: 1. In the chromosome number of 254 p. cervi, the haploid cell was n:9 and the diploid 2n=18. The meiotic divisions were observed frequently; 1,924 haploid and 32 diploid cells were reliable. Nine pairs of mitotic chromosomes were homologous in the metaphase stage, and the chromosomes were composed of five medium-sized metacentrics (m) , subtelocentrics(st) or submetacentrics(sm) and four small-siRed subtelocentrics(st) or submetacentrics(sm). Meiotic metaphase was composed of five medium and four small chromosomes in size. 2. As a series of C-banding method, C-band was showed in centromeric region from all of the haploid germ cells. Whereas chromosome No. 3 and 5 included heterochromatin on the tip region, chromosome No. 4 on the distal region and No. 6 proximal region. And chromosomes No. 2 and 8 showed a remarkable C-band distinguished from other chromosomes.

• Korean Journal of Microbiology
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• v.35 no.1
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• pp.28-34
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• 1999

Fragmentation vectors are used to analyze function and genomic structure of a gene of interest by creating deletion derivatives of large fragments of genomic DNA cloned as yeast artificial chromosomes (YACs). Herein, we developed a new hicistronic fragmentation vector that contains internal ribosomal entry sile (IRES) of encephalomyocarditis vin~s (EMCV) and $\beta$-galactosidase as a reporter gene. This vector system provides a novcl loo1 to analyze expression patterns of a gene of interest due to simultaneous expression of a target gene as well as $\beta$-galactosidase driven from a single message. In addition, the bicistronic fragmentation vector contains four rare-cutting restriction enzyme sites in the polycloning sites which can be used to conveniently insert any kinds of genes and therefore facilitates targeting DNA scgments into YAC by means of homologous recombination. This approach establishes a paradigm for manipulation of mammalian DNA segments and characterization of expression and regulatory regions of mammalian gene cloned as YAC.

• Journal of Genetic Medicine
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• v.7 no.2
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• pp.160-164
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• 2010

Structural abnormalities of the Y chromosome affect normal testicular differentiation and spermatogenesis. The present case showed a rare monocentric derivative Y chromosome with partial duplication of Yp including the SRY gene and deletion of Yq12 heterochromatin. The karyotype was 46,X,der(Y)(pter${\rightarrow}$q11.23::p11.2${\rightarrow}$pter).ish der(Y)(DYZ3+,DYZ1-,SRY++), confirmed through a FISH study. Even though the patient possessed an abnormal Y chromosome, testicular biopsy showed normal testicular volumes in the proband, with gonadal hormonal levels in the normal range but bilateral varicocele and hypospermatogenesis. We speculate that the abnormal Y chromosome arose from sister chromatids during Y chromosome recombination or intra chromosomal NAHR (non-allelic homologous recombination) during meiosis in the patient's father or in the very early stages of embryogenesis. The derivative Y chromosome might interfere in the meiotic stage of spermatogenesis, leading to the developmental arrest of germ cells. The present case illustrates that the infertility phenotype can have various causes. Also, it emphasizes the importance of accurate and various genetic analyses and could aid in male infertility treatment.

• Genomics & Informatics
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• v.21 no.4
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• pp.47.1-47.12
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• 2023

Silver barb (Barbonymus gonionotus) is among the most economically important freshwater fish species in Thailand. It ranks fourth in economic value and third in production weight for fisheries and culture in Thailand. An XX/XY sex-determination system based on gynogenesis was previously reported for this fish. In this study, the molecular basis underlying the sex-determination system was further investigated. Genome-wide single-nucleotide polymorphism data were generated for 32 captive-bred silver barb individuals, previously scored by phenotypic sex, to identify sex-linked regions associated with sex determination. Sixty-three male-linked loci, indicating putative XY chromosomes, were identified. Male-specific loci were not observed, which indicates that the putative Y chromosome is young and the sex determination region is cryptic. A homology search revealed that most male-linked loci were homologous to the Mariner/Tc1 and Gypsy transposable elements and are probably the remnants of an initial accumulation of repeats on the Y chromosome from the early stages of sex chromosome differentiation. This research provides convincing insights into the mechanism of sex determination and reveals the potential sex determination regions in silver barb. The study provides the basic data necessary for increasing the commercial value of silver barbs through genetic improvements.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.318-325
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• 2021

The objective of this study was to identify the effect of zebularine, a DNA methylation inhibitor, on the chromosomal association between homoeologous chromosomes in the wheat genetic background. Zebularine at a final concentration of 10 µM was used to treat the spikes of the double monosomic wheat addition line (DMA) with one Leymus mollis chromosome and one Leymus racemosus chromosome, both of which were in a homoeologous relationship. In late prophase, zebularine led to chromosome breakage in the Leymus homoeologous chromosomes. Chromosome breakage caused an increase in the frequency of chromosomal associations between the Leymus homoeologous chromosomes. Ordinary DMA showed 65 cells (35.3%) with chromosomal associations and 119 cells (64.7%) with no association, whereas treated DMA showed 102 cells (60.0%) with chromosomal associations and 67 cells (39.4%) with no association. In diakinesis, the Leymus bivalent showed a chromosomal association in the whole euchromatic region. In metaphase, the Leymus bivalent showed association in the whole chromosomal region, unlike other Leymus bivalents with partial chromosomal association. Chromosomal association by chromosome breakage occurred not only between Leymus chromosomes but also between Leymus and wheat chromosomes. The frequency of other chromosomal association (such as fusion and insert) was increased. Chromosome breakage by zebularine treatment is a useful method at the chromosome level as the spores with others are hereditary stable, although the homologous index (h) was not significantly different between ordinary DMA and treated DMA. It is necessary to study how to control zebularine treatment with a more stable concentration for chromosome breakage during meiosis.

• BMB Reports
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• v.51 no.9
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• pp.437-443
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• 2018

Non-homologous end joining (NHEJ), and to a lesser extent, the error-free pathway known as homology-directed repair (HDR) are cellular mechanisms for recovery from double-strand DNA breaks (DSB) induced by RNA-guided programmable nuclease CRISPR/Cas. Since NHEJ is equivalent to using a duck tape to stick two pieces of metals together, the outcome of this repair mechanism is prone to error. Any out-of-frame mutations or premature stop codons resulting from NHEJ repair mechanism are extremely handy for loss-of-function studies. Substitution of a mutation on the genome with the correct exogenous repair DNA requires coordination via an error-free HDR, for targeted transgenesis. However, several practical limitations exist in harnessing the potential of HDR to replace a faulty mutation for therapeutic purposes in all cell types and more so in somatic cells. In germ cells after the DSB, copying occurs from the homologous chromosome, which increases the chances of incorporation of exogenous DNA with some degree of homology into the genome compared with somatic cells where copying from the identical sister chromatid is always preferred. This review summarizes several strategies that have been implemented to increase the frequency of HDR with a focus on somatic cells. It also highlights the limitations of this technology in gene therapy and suggests specific solutions to circumvent those barriers.

• Journal of Microbiology and Biotechnology
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• v.26 no.8
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• pp.1473-1480
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• 2016

This study focused on the variations in the non-coding sequences between ctxB and rstR of various CTX phages. The non-coding sequences of CTX-1 and CTX-cla are phage type-specific. The length of the non-coding region of CTX-1 and CTX-cla is 601 and 730 nucleotides, respectively. The non-coding sequence of CTX phage could be divided into three regions. There is a phage type-specific Variable region between two homologous Common regions (Common regions 1 and 2). The non-coding sequence of RS1 element is similar to CTX-1 except that Common region 1 is replaced by a short RS1-specific sequence. The non-coding sequences of CTX-2 and CTX-cla are homologous, indicating the non-coding sequence of CTX-2 is derived from CTX-cla. The non-coding region of CTX-O139 is similar to CTX-cla and CTX-2; however, it contains an extra phage type-specific sequence between Common region 2 and rstR. The variations in the non-coding sequences of CTX phages might be associated with the difference in the replication efficiency and the directionality in the integration into the V. cholerae chromosome.

• Journal of Animal Science and Technology
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• v.51 no.5
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• pp.361-368
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• 2009

This study was carried out to establish the standard karyotype of Jeju horse by G-, C- and AgNOR-banding patterns. Blood samples were collected from 37 Jeju horses and 24 Thoroughbred that had been raised at the National Institute of Subtropical Agriculture in Jeju. The lymphocytes were cultured in vitro and then chromosomes prepared. The diploid chromosome number of Jeju horse is 64, which consists of 31 pairs of autosomes and X, Y sex chromosomes. The Jeju horse has 13 pairs of metacentric/submetacentric and 18 pairs of acrocentric autosomes. The X chromosome is the fifth largest submetacentric, while the Y chromosome is one of the smallest acrocentric chromosomes. The G-banding pattern of Jeju horse chromosomes showed a light band at centromeres in all autosomes, and also exhibited a typical and identical banding pattern in each homologous chromosome. Overall chromosomal morphology and positions of typical landmarks of the Jeju horse were virtually identical to those of International Committee for the Standardization of the Domestic Horse Karyotype. C-bands of Jeju horse chromosomes appeared on centromeres of almost all autosomes, but chromosome 8 showed a heterochromatin heteromorphism. The NORs in Jeju horse chromosomes showed polymorphic patterns within breed, individuals and cells. By the AgNOR staining, the NORs were located at the terminal of p-arm on chromosome 1 and near centromeres on the chromosome 26 and 31. The mean number of NORs per metaphase was 4.68 in Jeju horse.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.429-433
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• 1996

A Giemsa C-banding method was used for the identification of somatic chromosomes of Korean indigenous maize(Zea mays L.). Two Korean indigenous maize stocks and an American hybrid maize for comparison were examined. Ten deeply stained heterochromatic knobs whose position and size were different between the genotypes, two satellites and interstitial bands were observed. The length of homologous chromosomes compared by the relative lengths of chromosomes presented as a percentage of the length of chromosome 10 were different between the genotypes. The Giemsa method proved to be useful for the identification of somatic chromosomes and for the characterization of different stocks of Korean indigenous maize.