• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.364-371
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• 2017

The key to development of barnase-barstar transgene based hybrid seed technology is the availability of tightly regulated tapetum specific promoter, as any leaky expression of the barnase gene leads to several unintended effects. In the present study, we used two different tapetum specific promoters i.e. promoter of the RTS gene isolated from rice cultivar IR64 and the OsG6b promoter from japonica rice cultivar Hayayuki to express the barnase gene in rice transgenic lines. While viable male sterile transgenic lines could not be obtained with RTS promoter we could develop single copy male sterile lines when the barnase gene was expressed under the OsG6b promoter.

• Korean Journal of Poultry Science
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• v.36 no.2
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• pp.177-186
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• 2009

It is well-known that unregulated over-expression of foreign gene may have unwanted physiological or toxic effects in transgenic animals. To circumvent these problems, we constructed retrovirus vector designed to express the foreign gene under the control of the tetracycline-inducible promoter. However, gene expressions in the tetracycline-inducible expression system (Tet system) are not completely regulated but a little leaky due to the inherent defects in conventional Tet-based systems. A more tightly controllable regulatory system can be achieved when the advanced versions ($rtTA2^SM2$) of rtTA and a minimal promoter in responsive components (pTRE-tight) are used in combination therein. In this study, we tried to produce human thrombopoietin (hTPO) from various target cells and transgenic chickens using the retrovirus vector combined with Tet system. hTPO is the primary regulator of platelet production and has an important role in the survival and expansion of hematopoietic stem cells. In a preliminary experiment in vitro, higher hTPO expression and tighter expression control were observed in chicken embryonic fibroblast (CEF) cells. We also measured the biological activity of the hTPO using Mo7e cells whose proliferation is dependant on hTPO. The biological activity of the recombinant hTPO from CEF was higher than both its commercial counterpart and hTPO from other target cells. The recombinant retrovirus was injected beneath the blastoderm of non-incubated chicken embryos (stage X). Out of 138 injected eggs, 15 chicks hatched after 21 days of incubation. Among them, 8 hatched chicks were hTPO positive. When the Go transgenic chicken was fed doxycycline (0.5 mg per 1 gram of feed), a tetracycline derivative, hTPO concentration of the transgenic chicken blood was 200 ng/mL. Germline transmission of the transgene was confirmed in sperm of the Go transgenic roosters. These results are informative to establish transgenic chickens as bioreactors for the mass production of commercially valuable and biological active human cytokine proteins.

• Korean Journal of Animal Reproduction
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• v.27 no.1
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• pp.15-23
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• 2003

Lactadherin (formerly known as BA46), a major glycoprotein of the human milk fat globule membrane, is abundant in human breast milk and breast carcinomas and may prevent symptomatic rotavirus infections. In this study, under the control of tissue specific and hormonal inducible mouse whey acidic protein (WAP) promote., the expression pattern of lactadherin (Ltd) in lactogenic hormone-dependent mouse mammary epithelial cell line HC11 were tested. pLNWLtd construct containing 2.4 kilobases of the WAP promoter and 1.5 kilobases of human lactadherin gene was stably transfered into HC11 cells using retroviral vector system. Integration and expression level of the transgene was estimated using PCR and RT-PCR, respectively. Prominent induction of Ltd gene under the WAP promoter was accomplished in the presence of insulin, hydrocortisone and prolactin. Compared to the control (cells cultured with insulin alone), however we observed that the WAP promoter was leaky. These data indicate that luther studies are needed in finding an appropriate promoter other than WAP promoter because of its leakiness.

• Journal of Applied Biological Chemistry
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• v.48 no.4
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• pp.183-186
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• 2005

Arabidopsis AHL gene encodes a 3'(2')-phosphoadenosine 5'-phosphate (PAP)-specific phosphatase that plays a role in the sulfate activation pathway. We complemented E. coli cysQ mutant defective in cysteine biosynthesis with the AHL gene. AHL cDNA was cloned into the prokaryotic expression vector pKK388-1 and transformed into the bacterial mutant. Since cysQ mutant is a leaky cysteine auxotroph only under aerobic conditions, the bacteria were grown in liquid media with vigorous shaking to provide more aeration. In cysteine-free medium, cysQ mutant and the mutant harboring empty vector did not grow well, whereas cells harboring AHL cDNA exhibited significantly improved growth with doubling time of approximately 3 h. cysQ is known to encode a 3'(2'),5'-diphosphonucleoside 3'(2')-phosphohydrolase (DPNPase). However, our data suggest that cysQ protein has PAP-specific phosphatase activity in addition to DPNPase activity. Microbial complementation procedure described in this paper is useful for structure-activity studies of PAP-specific phosphatases identified from microbes and plants.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.72-72
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• 2003

The PAS factor, whose gene has been cloned from V vulnifcus, is a protein secretion factor. Although the role of the PAS factor in Vibrio is still unknown, it may be involved with the bacterial protein secretion. The PAS factor is a 76 amino acid polypeptide, and its expression in E. coli cells makes the host cell membrane leaky, resulting in the excretion of periplasmic proteins into the culture medium. Highly expressed PAS factor is harmful to the cell, this may be due to a disruption of the membrane structure or function.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.193-198
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• 2008

ErmSF is one of the proteins which are produced by Streptomyces fradiae to avoid suicide by its autogenous macrolide antibiotic, tylosin and one of ERM proteins which are responsible for transferring the methyl group to $A_{2058}$ (Escherichia coli coordinate) in 23S rRNA, which reduces the affinity of MLS (macrolide-lincosamide-streptogramin B) antibiotics to 23S rRNA, thereby confers the antibiotic resistance on microorganisms ranging from antibiotic producers to pathogens. ErmSF contains an extra N-terminal end region (NTER), which is unique to ErmSF and 25% of amino acids of which is arginine known well to interact with RNA. Noticeably, arginine is concentrated in $^{58}RARR^{61}$ and functional role of each arginine in this motif was investigated through deletion and site-directed mutagenesis and the activity of mutant proteins in cell R60 and R61 was found to play an important role in enzyme activity through the study with deletion mutant up to R60 and R61. With the site-directed mutagenesis using deletion mutant of 1 to 59 (R60A, R61A, and RR60, 61AA), R60 was found more important than R61 but R61 was necessary for the proper activity of R60 and vice versa. And these amino acids were presumed to assume a secondary structure of $\alpha$-helix.