• Microbiology and Biotechnology Letters
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• v.14 no.3
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• pp.219-223
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• 1986

In order to preparr the hybridoma cells which produce a monoclonal antibody to human fibroblast interferon(Hu IFN-$\beta$), spleen cells from BALB/cmice immunized with the purified Hu IFN-$\beta$ were fused with NS-O cells, a myeloma cell line. Forty hybrids with high titer among 1300 hybrids Isolated by an ELISA screening method were subcloned using the soft agarose cloning and limiting dilution methods, and 11 hybrids were selected. As a result of iso-typing the hybrids using the mouse monoclonal typing kit, two hybridomas were found to produce 1gG 2a type of monoclonal an-tibodies. The ascites fluid from nude mice inoculated intraperitoneally with the above hybridomas was removed and purified using a protein A-Sepharose CL-4B. Monoclonal antibody was proven to have only the heavy and light chains on SDS-polyacrylamide gel electrophoresis.

• BMB Reports
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• v.33 no.5
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• pp.396-401
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• 2000

A differential display method is used to identify novel genes whose expression is affected by treatment with ferric ammonium citrate (FAC) or desferrioxamine (DFO), an iron chelating agent in the human hepatoblastoma cell line (HepG2). These chemicals are known to deplete or increase the intracellular concentration of iron, respectively. Initially, we isolated seventeen genes whose expressions are down- or up regulated by the treatment of the chemicals, as well as their four differentially expressed genes that are designated as clone-1, -2, -3, and -4. These are further characterized by cDNA sequencing and Northern blot analysis. Through the cDNA sequencing, as well as comparing them to genes published using the NCBI BLAST program, we identified the sequence of the clone-1 that is up-regulated by the treatment of DFO. It is identical to the human insulin-like growth factor binding protein-1 (IGFBP-1). This suggests that the IGFBP-1 gene in the HepG2 cell is up-regulated by an iron depletion condition. Also, the expression of the clone-3 and -4 is up-regulated by FAC treatment and their eDNA sequences are identical to the human ferritin-fight chain and human NADH-dehydrogenase, respectively. However, the sequence of the clone-2 has no significant homology to any other known gene. Therefore, we suggest that changes of the cellular iron level in the HepG2 cell affects the transcription of cellular genes. This includes human IGFBP-1, ferritin-fight chain, and NADH-dehydrogenase. Regulation of these gene expressions may have an important role in cellular functions that are related to cellular iron metabolism.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.363-368
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• 1988

Molecular cloning of gene for $\alpha$-acylamino-$\beta$-lactam acylhydrolase (ALAH) III from Acetobacter turbidans has been attempted by immunochemical detection method, in which polyclonal antibody from mouse Balb/c against this enzyme was employed as a probe. As a cloning vector, λ gtll was chosen for this purpose. Two positive clones has been selected from genomic libraries of A. turbidans, which had somewhat different binding affinities on anti-ALAH III umm and anti-$\beta$-galactosidase. By restriction analysis, both clones has been turned out to lose one of EeoRI sites. From these results, it concluded that deletion of DNA between lacZ gene and inserted DNA has occurred during replication of these clones in host cells.

• Nuclear Engineering and Technology
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• v.13 no.3
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• pp.161-167
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• 1981

For determination of mutation frequency induced by chronic irradiation of low dose gamma rays, Tradescarrfia clone 4430 was exposed to Co-60 ${\gamma}$ rays with different exposure rates from 3.6mR/day to 182R/day in or out of the Gamma Field at Kumkok Experiment Farm of KAERI. Somatic mutations based on pink mutant events of the stamen hair cells were clearly observed by the treatment. The pink mutant events were increased proportionally with increasing exposure rates of gamma ray except for relatively high dose rates of 105 R/day and 182 R/day, indicating saturation effect of mutation. The somatic pink mutations could be fairly detectable even in the low dose rate of 3.6mR/day. Therefore, this stamen hair system of Tradescantia clone 4430 seemed to be an reasonable test system for detecting mutability of low level irradiation. These results imply that artificial mutation induction in the fruit and ornamental trees could be expected in the ${\gamma}$-field.

• Animal cells and systems
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• v.2 no.1
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• pp.113-116
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• 1998

A cDNA clone coding for ribosomal protein 46 (rp46) which is a component of 60S ribosomal large subunit has been identified from Drosophila melanogaster. A cDNA clone encoding S. cerevisiae rp46 was used as a probe to screen a Drosophila larvae cDNA library. The DNA sequence analysis revealed that the cDNA coding for Drosophils rp46 contains a complete reading frame of 153 nucleotides coding for 51 amino acids. The deduced amino acid sequence showed 71-75% homology with those of other eukaryotic organisms. Northern blot analysis showed that about 1-kb rp46 transcripts are abundant throughout fly development. Whole mount embryonic mRNA in situ hybridization also showed no preferential distribution of the transcripts to any specific region. The chromosomal in situ hybridization revealed that the identified gene is localized at position 60C on the right arm of the second polytene chromosome with a possibility of single copy.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.3-6
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• 2003

The birth of the clone animals is influencing the frontier of research of animal biotechnology. It has effects on research of animal biotechnology itself by necessitating setting of new research subjects, modifications of the strategy of ongoing research projects, and challenges to schemes formerly considered impossible. In my talk, such topics including mass production of fertile ova and oocyte maturation will be discussed. (1) Oocytes are needed for the production of a clone by nuclear transplantation. Mitochondrial DNA inherited via the oocyte are involved also in the morphogenesis. Therefore, oocytes from the same animal must be used as recipients to produce genuine clones by nuclear transplantation. Experimenting on the assumption that selective oogenesis can be avoided, and apoptosis of oocytes can be prevented, by using ovarian angiogenic factos will be introduced. (2) It is important to clarify the factors of oocytes involving in reprogramming of somatic cells. Such factors are thought to be expressed in oocytes during oogenesis and oocyte maturation. Therefore, molecular mechanisms of oogenesis and oocyte maturation must be clarified extensively. Topics in this field including our recent advances will be discussed. (중략)

• BMB Reports
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• v.30 no.3
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• pp.200-204
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• 1997

We eliminated introns from replication independent chicken H3.3 histone gene using a H3.3 cDNA clone and a genomic H3.3 clone. After introduction into Rat 3 cells, we observed its pattern of expression by analyzing mRNA from different phases of the cell cycle. Even without introns, the H3.3 gene was expressed constitutively at a low level throughout the cell cycle. This indicates that the introns in the H3.3 gene are not responsible for the cell cycle-independent expression of the gene. This result contradicts previous reports that suggested their importance in cell cycle regulated expression. We believe that other regions of the gene, promoter, coding region, and/or 3'-end of the gene, are involved in its expression pattern.

• Microbiology and Biotechnology Letters
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• v.21 no.6
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• pp.542-548
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• 1993

Bacillus stearothermophilus was shown to express multiple xylanolytic enzymes including acetyl xylan esterase. Genomic DNA of the strain partially digested with HindIII was ligated into the HindIII site of pBR322, and expressed in E. coli HB101 cells in order to clone the gene for acetyl xylan esterase. One transformant among 4000 screened formed a clear zone around its colony on the LB agar supplemented with 1.0% tributyrin. The functional clone harbored the recombinant plasmid pKMG5 with an insert of 5.1kb.

• YAKHAK HOEJI
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• v.42 no.5
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• pp.480-486
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• 1998

Many antitumor and immune modulating components have been isolated from fungal extracts. In this study, the authors isolated the proteoglycans from cultured mycelia of Lentin us lepideus, including especially the acidic polysaccharide fraction, named lepidan. It was obtained by extraction with hot water followed by purification using DEAE cellulose anion exchange. To elucidate antitumor effects against different type of tumor, the proteoglycans were tested on sarcoma 180, C3H MCA clone 16 and P388 leukemia in vivo. Lepidan showed 58.3% of tumor inhibition against solid form of sarcoma 180 and 58.6% against MCA clone 16. But lepidan did not affect life span of mice against P388 leukemia. Also when Lepidan was applicated to MTT assay, it did not show any direct cytotoxicity against various tumor cells in vitro.

• International Journal of Industrial Entomology and Biomaterials
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• v.39 no.1
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• pp.22-28
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• 2019

We previously isolated 9 clones that show stronger signal compared to Bombyx mori cytoplasmic actin gene (BmA3) by using a dot blot hybridization. In this study, we focused on one clone among these clones which has high amino acid similarity with ${\beta}$-tubulin gene of B. mori. This clone was ubiquitously expressed in all tissues and developmental stage of B. mori. As result of promoter assay using dual luciferase assay system, we found the highest transcription activity region (-750/-1) in the 5'-flanking region of ${\beta}$-tubulin gene, which has about 47 fold more intensive promoter activity than BmA3 promoter. Moreover, the ${\beta}$-tubulin promoter was normally regulated in Bm5, Sf9, and S2 cells. Therefore, we suggest that ${\beta}$-tubulin promoter may be used more powerful and effectively for transgene expression in various insects containing B. mori as a universal promoter.