• The Korean Journal of Nuclear Medicine
• /
• v.38 no.2
• /
• pp.115-120
• /
• 2004

Molecular imaging is a rapidly growing field due to the advances in molecular biology and imaging technologies. With the introduction of imaging reporter genes into the cell, diverse cellular processes can be monitored, quantified and imaged non-invasively in vivo. These precesses include the gene expression, protein-protein interactions, signal transduction pathways, and monitoring of cells such as cancer cells, immune cells, and stem cells. In the near future, molecular imaging analysis will allow us to observe the incipience and progression of the disease. These will make us easier to give a diagnosis in the early stage of intractable diseases such as canter, neuro-degenerative disease, and immunological disorders. Additionally, molecular imaging method will be a valuable tool for the real-time evaluation of cells in molecular biology and the basic biological studies. As newer and more powerful molecular imaging tools become available, it will be necessary to corporate clinicians, molecular biologists and biochemists for the planning, interpretation, and application of these techniques to their fullest potential. in order for such a multidisciplinary team to be effective, it is essential that a common understanding of basic biochemical and molecular biologic techniques is achieved. Basic molecular techniques for molecular imaging methods are presented in this paper.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.5 no.5
• /
• pp.320-326
• /
• 2000

Promoters of the genes G3P, ICL1, POT1, POX1, POX2 and POX5 of the yeast Y. lipolytica were studied in respect to their regulations and activities during growth on different carbon sources. The aim of this study was to select suitable promoters for high expression of heterologous genes in this yeast. For this purpose the promoters were fused with the reporter gene lacZ of E. coli and integrated as single copies into the genome of Y. lipolytica strain PO1d. The measurement of expressed activities of ${\beta}$-galactosidase revealed that pICL1, pPOX2 and pPOT1 are the strongest regulable promoters available for Y. lipolytica, at present. pPOX2 and pPOT1 were highly induced during growth on oleic acid and were completely repressed by glucose and glycerol. pICL1 was strongly inducible by ethanol besides alkanes and fatty acids, however, not completely repressible by glucose or glycerol. Ricinoleic acid methyl ester appeared as a very strong inducer for pPOT1 and pPOX2, in spite of that it inhibited growth of Y. lipolytica transformants.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.4
• /
• pp.1165-1169
• /
• 2013

To elucidate the role of PKG isoforms in transcriptional control of cyclin D1, we employed a series of expression vectors of PKG $1{\alpha}$ and PKG $1{\beta}$ which encode HA-tagged wild type and constitutively active (SD and ${\Delta}N$) mutants. Our present study demonstrates that both the constitutively active mutants of PKG $1{\beta}$ downregulate the transcription of cyclin D1 when transiently transfected in NIH3T3 cells, whereas PKG $1{\alpha}$ mutants show weak inhibition. We further studied the transcriptional regulators of cyclin D1, such as, c-fos, NF-${\kappa}B$, and CRE by using the luciferase reporter assay. Constitutively active mutants of PKG $1{\beta}$ showed marked transcriptional downregulation of c-fos in NIH3T3 cells, whereas PKG $1{\alpha}$ downregulated c-fos to a lesser extent. We also found that the constitutively active mutants of PKG negatively regulated the activation of NF-${\kappa}B$ and CRE, suggesting their involvement in the regulation of cyclin D1.

• Food Science of Animal Resources
• /
• v.39 no.1
• /
• pp.13-22
• /
• 2019

This study aimed to develop a bile-responsive expression system for lactobacilli. The promoters of four genes, encoding phosphoenolpyruvate-dependent sugar phosphotransferase (mannose-specific), L-lactate dehydrogenase (LDH), HPr kinase, and D-alanine-D-alanine ligase, respectively, which were highly expressed by bile addition in Lactobacillus johnsonii PF01, were chosen. Each promoter was amplified by polymerase chain reaction and fused upstream of the ${\beta}$-glucuronidase gene as a reporter, respectively. Then, these constructs were cloned into E. coli-Lactobacillus shuttle vector pULP2, which was generated by the fusion of pUC19 with the L. plantarum plasmid pLP27. Finally, the constructed vectors were introduced into L. plantarum for a promoter activity assay. The LDH promoter showed the highest activity and its activity increased 1.8-fold by bile addition. The constructed vector maintained in L. plantarum until 80 generations without selection pressure. A bile-responsive expression vector, $pULP3-P_{LDH}$, for Lactobacillus spp. can be an effective tool for the bile-inducible expression of bioactive proteins in intestine after intake in the form of fermented dairy foods.

• Journal of fish pathology
• /
• v.34 no.1
• /
• pp.17-22
• /
• 2021

Eukaryotic translation is initiated by either cap-dependent or cap-independent way, and the cap-independent translation can be initiated by the internal ribosomal entry site (IRES). In this study, to know whether the 5'UTR leader sequence of marine birnavirus (MABV) segment A and segment B can act as IRES, bicistronic vectors harboring a CMV promoter-driven red fluorescent gene (mCherry) and poliovirus IRES- or MABV's leader sequence-driven green fluorescent gene (eGFP) were constructed, then, transfected into a mammalian cell line (BHK-21 cells) and a fish cell line (CHSE-214 cells). The results showed that the poliovirus IRES worked well in BHK-21 cells, but did not work in CHSE-214 cells. In the evaluation of MABV's leader sequences, the reporter eGFP gene under the 5'UTR leader sequence of MABV's segment A was well-translated in CHSE-214 cells, indicating 5'UTR of MABV's segment A initiates translation in the cap-independent way and can be used as a fish-specific IRES system. However, the 5'UTR leader sequence of MABV's segment B did not initiate translation in CHSE-214 cells. As the precise mechanism of birnavirid IRES-mediated translation is not known, more elaborate investigations are needed to uncover why the leader sequence of segment B could not initiate translation in the present study. In addition, further studies on the host species range of MABV's segment A IRES and on the screening of other fish-specific IRESs are needed.

• The Korean Journal of Zoology
• /
• v.38 no.4
• /
• pp.550-556
• /
• 1995

The c-myc proto-oncogene is Involved In the control of normal cell proliferation and differentiation of many cell lineages. Although it has heen suggested that c-myc may play an important role in the mammalian early development, it Is unclear whether the embryonic c-myc mRNA is originated from zygotic gene expression or stored maternal message. Thus, we have construded expression vectors, In which the 5, flanking sequences including c-myc promoter region and a large non-coding exon I are fused 'sith E. coli lacZ gene that encedes $\beta$-galactosldase as a reporter. As c-myc exon I contains a modulatory sequence, we designed t, vo types of vectors (pcmyc.Gall and pcmyc-Ga12) to examine the role of exon I in c-myc expression. The former contains the complete exon I and the later has a deletion in 40 bp of modulator sequence located In the exon I of c-myc These vectors were microInjected into fertilized one-cell embryos and $\beta$-galactosidase activity was examined by X-gal staining during early embryogenesis. $\beta$-galactosidase activity derived from c-myc promoter was decreased at two-cell stage. The expression level directed by pcmyc- Ga12 was similar to that of pcmyc-Gal1, indicating that the medulatory sequence in exon I may not be Involved at least In the regulation of embryonic c-myc expression. In summary, the present study indicates that the c-myc promoter is functional at the early stage embryo, and the regulation of c-myc expression is under the control of "zygotic" clock of preimplantation mouse embryos.e embryos.

• Microbiology and Biotechnology Letters
• /
• v.39 no.4
• /
• pp.337-344
• /
• 2011

Integrase MJ1 from the bacteriophage ${\Phi}FC1$ carries out recombination between two DNA sequences (the phage attachment site, attP and the bacterial attachment site, attB) in NIH3T3 mouse cells. In this study, the integration vector containing attP, attB and the integrase gene MJ, was constructed. The integration mediated by integrase MJ1 in Escherichia coli led to excision of LacZ. Therefore, the frequency of integration was measured by the counting of the white colony, which is detectable on X-Gal plates. The extrachromosomal integration in NIH3T3 mouse cells was monitored by the expression of the green fluorescent protein (GFP) as a reporter. To demonstrate integration mediated integrase MJ1 in NIH3T3 cells, vectors containing attP and attB were co-transfected into NIH3T3 cells. The integration was confirmed by fluorescent microscopy. The expression of GFP was induced in NIH3T3 cells expressing MJ1 without accessory factors. By contrast, the excision mediated by the MJ1 between attR and attL had no effect on the expression of GFP. These results suggest that integrase MJ1 may enable a variety of genomic modifications for research and therapeutic purposes in higher living cells.

• Asian-Australasian Journal of Animal Sciences
• /
• v.21 no.5
• /
• pp.745-753
• /
• 2008

Gene-manipulated mice were discovered for the first time about a quarter century ago. Since then, numerous sophisticated technologies have been developed and applied to answer key questions about the fundamental roles of the genes of interest. Functional genomics can be characterized into gain-of-function and loss-of-function, which are called transgenic and knock-out studies, respectively. To make transgenic mice, the most widely used technique is the microinjection of transgene-containing vectors into the embryonic pronucleus. However, there are critical drawbacks: namely position effects, integration of unknown copies of a foreign gene, and instability of the foreign DNA within the host genome. To overcome these problems, the ROSA26 locus was used for the knock-in site of a transgene. Usage of this locus is discussed for the gain of function study as well as for several brilliant approaches such as conditional/inducible transgenic system, reproducible/inducible knockdown system, specific cell ablation by Cre-mediated expression of DTA, Cre-ERTM mice as a useful tool for temporal gene regulation, MORE mice as a germ line delete and site specific recombinase system. Techniques to make null mutant mice include complicated steps: vector design and construction, colony selection of embryonic stem (ES) cells, production of chimera mice, confirmation of germ line transmission, and so forth. It is tedious and labor intensive work and difficult to approach. Thus, it is not readily accessible by most researchers. In order to overcome such limitations, technical breakthroughs such as reporter knock-in and gene knock-out system, production of homozygous mutant ES cells from a single targeting vector, and production of mutant mice from tetraploid embryos are developed. With these upcoming progresses, it is important to consider how we could develop these systems further and expand to other animal models such as pigs and monkeys that have more physiological similarities to humans.

• BMB Reports
• /
• v.51 no.8
• /
• pp.388-393
• /
• 2018

The activating transcription factor (ATF) 4 belongs to the ATF/CREB (cAMP Response Element Binding bZIP [Basic Leucine Zipper]) transcription factor family, and plays a central role in the UPR (Unfolded Protein Response) process in cells. The induction of ATF4 expression has previously been shown to increase the replication of HIV-1. However, the detailed mechanism underlying this effect and the factors involved in the regulation of ATF4 function are still unknown. Here, we demonstrate first that knocking out ATF4 using siRNA shows a strong negative effect on HIV-1 production, indicating that ATF4 is a functional positive cellular factor in HIV-1 production. To determine the mechanism by which ATF4 regulates the HIV-1 life cycle, we assessed the effect of the overexpression of wild type ATF4 and its various derivatives on HIV-1 LTR-mediated transcriptional activation and the production of HIV-1 particles. This effect was studied through co-transfection experiments with either reporter vectors or proviral DNA. We found that the N-terminal domains of ATF4 are involved in HIV-1 LTR-mediated transcriptional activation, and thus in HIV-1 production.

• Journal of Plant Biotechnology
• /
• v.31 no.4
• /
• pp.255-259
• /
• 2004

Agrobacterium tumefaciens-mediated cotyledonary node transformation was used to produce transgenic soybean. Cotyledonary node explants of three cultivars and one genotype were co-cultivated with strains Agrobacterium (LBA4404, GV3101, EHA101, C58) containing the binary vectors (pCAMBIA3301 and pPTN289) carrying with CaMV 35S promoter-GUS gene as reporter gene and NOS promoter-bar gene conferring resistance to glufosinate (herbicide Basta) as selectable marker. There was a significant difference in the transformation frequency depend on bacteria strain. The EHA101 strain of the bacterial strains employed gave the maximum efficiency (3.6%). One hundred-six lines transformed showed the resistance in glufosinate. Histochemical GUS assay showed that at least 11 plants transformed with the GUS gene were positive response. The soybean transformants were obtained from the Thorne (5 plants), 1049 (5 plants) and Bakun (1 plant), respectively. Southern blot analysis and leaf painting assay revealed that the GUS and bar gene segregated and expressed in their progeny.