• Genomics & Informatics
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• v.3 no.1
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• pp.24-29
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• 2005

TRPV2 is a non-specific cation channel expressed in sensory neurons, and activated by noxious heat. Particularly, TRPV2 has six transmembrane domains and three ankyrin repeats. TRPV2 has been cloned from various species such as human, rat, and mouse. Oocytes of Xenopus laevis - an African clawed frog ­have been widely used for decades in characterization of various receptors and ion channels. The functional property of rat TRPV2 was also identified by this oocyte expression system. However, no TRPV2 orthologue of Xenopus laevis has been reported so far. Hence, we have focused to clone a TRPV2 orthologue of Xenopus laevis with the aid of bioinformatic tools. Because the genome sequence of Xenopus laevis is not available until now, a genome sequence of Xenopus tropicalis - a close relative species of Xenopus laevis - was used. After a number of bioinformatic searches in silico, a predicted full-length sequence of TRPV2 orthologue of Xenopus tropicalis was found. Based on this predicted sequence, various approaches such as RT-PCR and 5' -RACE technique were applied to clone a full length of Xenopus laevis TRV2. Consequently, a full-length Xenopus laevis TRPV2 was cloned from heart cDNA.

• Journal of Applied Biological Chemistry
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• v.53 no.4
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• pp.189-194
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• 2010

We confirmed the hypo-osmotic shock strengths and duration, different type of vectors, and subcelluar localization to identify the optimum analysis condition of plant aquaporin activity in Xenopus ooctye using Arabidopsis thaliana AtPIP2-1 gene. Six minutes and 1/5ND buffer hypoosmotic shock treatment was the best condition to show the maximum swelling of Xenopus oocytes where AtPIP2-1 was expressed using pcDNA3.1 vector. AtPIP2-1 protein was expressed more efficiently in pGEMHE vector which has 5' and 3' UTR (untranslation region) of Xenopus ${\beta}$-GLOBIN gene in multiple cloning site than in pcDNA3.1 vector. Also green fluorescence of GFP fused to AtPIP2-1 was detected onto oocyte plasmamembrane where is the proper subcellular localization target of AtPIP2-1.

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.241.2-241
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• 1995

No Abstract, See Full Text

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.614-618
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• 2001

Low-threshold T-type $Ca^{2+}$ channels are distinctive voltage-operated gates for external $Ca^{2+}$ entry around a resting membrane potential due to their low voltage activation. These phenomena have already been extensively studied due to their relevance in diverse physiological functions. Recently, three T-type $Ca^{2+}$ channel ${\alpha}$$_1$subunits were cloned and their biophysical properties were characterized after expression in mammalian expression systems. In this study, ${\alpha_IG} and {\alpha_IH}$ low-threshold $Ca^{2+}$ channels were expressed and characterized in Xenopus oocytes after adding 5' and 3'untranslated portions of a Xenopus ${\beta}$ globin to improve their expression levels. The added portions dramatically enhanced the expression levels of the ${\alpha_IG} and {\alpha_IH}$ T-type channels. When currents were recorded in 10 mM $Ba^{2+}$ as the charge carrier, the activation thresholds were about -60 mV, peak currents appeared at -20 mV, and the reversal potentials were between +40 and +45. The activation time constants were very similar to each other, while the inactivation time constants of the ${\alpha_IG}$ currents were smaller than those of ${\alpha_IH}$. Taken together, the electrophysiological properties of the ${\alpha_IG} and {\alpha_IH}$ channels expressed in Xenopus oocytes were similar to the previously reported characteristics of low-threshold $Ca^{2+}$ channel currents.

• Animal cells and systems
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• v.5 no.1
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• pp.85-90
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• 2001

Yolk platelets, one of the main food stores in the embryonic development, are composed of proteins. However, little is known about the identity of proteins utilized at certain stages of embryogenesis. In this study, we followed the fates of embryonic storage proteins by using an anti-polyubiquitin monoclonal antibody (mAB) as a probe. The mAb recognized the major storage proteins of Drosophila, Xenopus and chicken eggs. In the Drosophila embryo, the mAb-reactive 45-kDa protein was not used until stage 11 but was used up at stage 16 when the embryo completed segmentation. In the Xenopus embryo, the mAb-reactive 111 kDa protein was mostly utilized between stages 42 and 45 implying that the protein might be an energy source used just prior to feeding on food. By N-terminal sequencing the storage protein of Xenopus embryo was identified as a lipovitellin 1. This study confirms that storage proteins are used almost simultaneously at certain stages of embryogenesis and that vitellogenin 1 is the last storage protein in Xenopus embryogenesis.

• The Korean Journal of Zoology
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• v.37 no.2
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• pp.137-143
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• 1994

Microiniection of genes Into Xenopus laeuis oocvtes in highly useful in the annvsis of gene regulation, since a large number of oocvtes can be injected in a relatively short time. The GRP78 enhancer has been identified to a 291-bp fragment that spans a region of GRP78 promoter between -378 and -87 (Lin et at., 1986: Kim and Lee, 1989). We examined whether this GRP78 enhancer is effective in directing expression of heterologous gene in Xenopus laeuis oocytes. The chloramphenicol acetvltransferase (CAT) fusion constructs containing the GRP78 promoter and the SV4O early promoter were constructed and were injected into nuclei of Xencpus laeuis oocvtes. The recipient oocvtes were then assayed for CAT activity. The fusion constructs exhibited higher activity as compared to SV40 promoter tested here. The GRP78 enhancer showed 8.5- to 9.2-fold enhancement over that of the SV4O promoter. The orientation of GRP78 enhancer with respect to the direction of CAT transcription unit had no significant effect. Thus, the GRP78 enhancer is a viable candidate for the construction of expression system for use in Xenopus laevss oocvtes and will be important for the studY of a gene expression throughout development.

• Molecules and Cells
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• v.19 no.3
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• pp.310-317
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• 2005

The Xenopus FGF-8a and FGF-8b isoforms have been reported to be neural crest and neuronal inducers, respectively. However, cloning of Xenopus FGF-8b (XFGF-8b) has not been reported previously and the two isoforms do not seem to have been clearly distinguished in Xenopus experiments. Here, we describe the cloning and expression of XFGF-8b and compare the effects of the two isoforms. XFGF-8b has an 11 amino acid insert in its N-terminal region compared with XFGF-8a. Both isoforms are expressed in the anterior neural regions of the early embryo, and in the apical ectodermal ridge of limb buds and tips of growing digits in the larval stages. However, XFGF-8b is more abundant than XFGF-8a throughout early development. The two isoforms are also regulated in similar fashion by retinoic acid in early development. However, although both XFGF-8a and XFGF-8b induce ectopic neurogenesis, only XFGF-8a appears to be involved in neural crest induction.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.326-326
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• 1994

중금속이 양서류의 발생에 미치는 영향을 알아보기 위해 Xenopus embryo 2 할구기부터 카드뮴, 수은, 납. 구리, 아연 등을 여러 농도로 지속적으로 처리한 후 치사율과 이상 발생율을 조사하였다 그 결과 수은, 카드뮴. 구리, 납. 아연의 순으로 독성이 강함을 알 수 있다. 중금속 중 카드뮴 처리시 나타나는 현상으로는 창자, 눈, 체축. 지느러미, 십장 등의 이상과 수포 등을 들 수 있다. FETAX (frog Embryo Teratogenesis Assay : Xenopus)의 분석 결과 LC$_{100}$ 은 1.5 ppm, EC$_{100}$은 1PPm 이었고 기형 유발지수(TI)가 2. 8 인 점으로 보아 카드뮴을 Xenopus embryo에 있어서 기형유발원으로 분류할 수 있다.

• Animal cells and systems
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• v.1 no.3
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• pp.491-496
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• 1997

When olfactory placodes are transplanted at stages 23/24 from Xenopus laevis to Xenopus borealis hosts of the same age, it is possible to distinguish the cell populations of the host and donor due to the peculiar nuclear Q bands specific to X. borealis. I have replaced the eye anlage in each of a number of X. borealis with the transplanted olfactory placode of an individual X. laevis, or vice versa. In most instances, the placode of the donor fuses with that of the host. When fusion occurs, but not when the host and donor orqans grow separately, the cells of the donor were replaced gradually and according to a characteristic pattern by cells of the host. The basal cells of the donor were the first to be replaced, followed by the more matured cells of the sensory epithelium. This cellular substitution, proceeding in an orderly fashion from bottom to upper layers of the epithelium, depends on the fusion of the two organs. This observation suggests intercellular contacts in the mitotic zone of the two organs favor the host's cells over those of the donor.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.2
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• pp.157-163
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• 2001

The effects of dimethyl sulfoxide (DMSO) were studied in two groups of Xenopus oocytes, one expressing ATP sensitive $K^+\;(K_{ATP})$ channel comprised of sulfonylurea receptor SUR1 and inwardly rectifying $K^+$ channel subunit Kir6.2, and the other expressing renal $K_{ATP}$ channel ROMK2. At concentrations of $0.3{\sim}10%$ (vol/vol) DMSO inhibited whole cell Kir6.2/SUR1 currents elicited by bath application of sodium azide (3 mM) in a concentration-dependent manner. The inhibition constant and Hill coefficient were 2.93% and 1.62, respectively. ROMK2 currents, however, was not affected significantly by DMSO. The results support the idea that DMSO inhibits $K_{ATP}$ channel expressed in Xenopus oocyte through a protein-specific mechanism(s) that remains to be further elucidated.