• Biomedical Science Letters
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• v.12 no.4
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• pp.343-348
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• 2006

Drosophila Sog and vertebrate Noggin play important roles during development. They function as antagonists against BMP4 signaling and induce neural ectoderm during embryogenesis. They are also engaged in appendage formation by inhibiting BMP4 signaling during late development. To understand further functions of Sog, Supersog, which is a more potent form of Sog, and Noggin BMP4 antagonists during development, I performed the molecular genetic analysis using Drosophila embryogenesis and wing formation as assay systems. In cellular blastoderm embryos, Sog inhibited Dpp signaling, Drosophila BMP4 signaling, whereas Supersog or Noggin did not block Dpp signaling. During wing formation, Sog inhibited Sax type I receptor of Dpp signaling whereas Noggin inhibited Tkv type I receptor of Dpp signaling. However, Supersog inhibited both Sax and Tkv type I receptors. These results suggest that functions of BMP4 antagonists are developmental stage dependent and indicate that each BMP4 antagonist inhibits BMP4 signaling by blocking different BMP4 receptors.

• BMB Reports
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• v.47 no.9
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• pp.518-523
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• 2014

The maternal transcription factor Dorsal (Dl) functions as both an activator and a repressor in a context-dependent manner to control dorsal-ventral patterning in the Drosophila embryo. Previous studies have suggested that Dl is an intrinsic activator and its repressive activity requires additional corepressors that bind corepressor-binding sites near Dl-binding sites. However, the molecular identities of the corepressors have yet to be identified. Here, we present evidence that Capicua (Cic) is involved in Dl-mediated repression in the zerkn$\ddot{u}$llt (zen) ventral repression element (VRE). Computational and genetic analyses indicate that a DNA-binding consensus sequence of Cic is highly analogous with previously identified corepressor-binding sequences and that Dl failed to repress zen expression in lateral regions of cic mutant embryos. Furthermore, electrophoretic mobility shift assay (EMSA) shows that Cic directly interacts with several corepressor-binding sites in the zen VRE. These results suggest that Cic may function as a corepressor by binding the VRE.

• 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.

• BMB Reports
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• v.45 no.10
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• pp.577-582
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• 2012

single-minded (sim) is a master regulatory gene that directs differentiation in the central nervous system during Drosophila embryogenesis. Recent identification of the mesectoderm enhancer (MSE) of sim has led to the hypothesis that two Snail (Sna)-binding sites in the MSE may repress sim expression in the presumptive mesoderm. We provide evidence here that three Sna-binding sites proximal to the sim promoter, but not those of the MSE, are responsible for the mesodermal repression of sim in vivo. Using transgenic embryos injected with lacZ transgenes, we showed that sim repression in the mesoderm requires the three promoter-proximal Sna-binding sites. These results suggest that Sna represses the mesectodermal expression of sim by directly repressing the nearby promoter, and not by quenching adjacent transcriptional activators in the MSE. These data also showed how the MSE, lacking the three proximal Sna-binding sites, reproduced the endogenous pattern of sim expression in transgenic embryos.

• BMB Reports
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• v.47 no.6
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• pp.354-359
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• 2014

The types of glia in the central nervous system (CNS) of the Drosophila embryo include longitudinal glia (LG), cell body glia (CBG), and peripheral glia (PG). Transcription factors, such as glial cell missing and reverse polarity, are well-established general glial cell markers. Only a few glial cell-specific markers have been identified in the Drosophila embryonic CNS, thus far. In the present study, we employed the glial cell-specific markers for LG (vir-1/CG5453 and CG31235), CBG (fabp/CG6783 and CG11902), and PG (CG2310 and moody/CG4322), and comprehensively analyzed their expression patterns, during the embryonic CNS development. Our study validated the specificity of a set of glial markers, and further revealed their spatio-temporal expression patterns, which will aid in the understanding of the developmental lineage, and investigating their role in the development and homeostasis of the Drosophila CNS in vivo.

• Molecules and Cells
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• v.27 no.5
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• pp.583-589
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• 2009

GTP cyclohydrolase I (GTPCH) is a key enzyme in the de novo synthesis of tetrahydrobiopterin. Previously, the Drosophila melanogaster GTPCH gene has been shown to be expressed from two different promoters (P1 and P2). In our study, the 5'-flanking DNA regions required for P1 and P2 promoter activities were characterized using transient expression assay. The DNA regions between -98 and +31, and between -73 and +35 are required for efficient P1 and P2 promoter activities, respectively. The regions between -98 and -56 and between -73 and -41 may contain critical elements required for the expression of GTPCH in Drosophila. By aligning the nucleotide sequences in the P1 and P2 promoter regions of the Drosophila melanogaster and Drosophila virilrs GTPCH genes, several conserved elements including palindromic sequences in the regions critical for P1 and P2 promoter activities were identified. Western blot analysis of transgenic flies transformed using P1 or P2 promoter-lacZ fusion plasmids further revealed that P1 promoter expression is restricted to the late pupae and adult developmental stages but that the P2 promoter driven expression of GTPCH is constitutive throughout fly development. In addition, X-gal staining of the embryos and imaginal discs of transgenic flies suggests that the P2 promoter is active from stage 13 of embryo and is generally active in most regions of the imaginal discs at the larval stages.

• BMB Reports
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• v.49 no.10
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• pp.572-577
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• 2016

The short gastrulation (sog) shadow enhancer directs early and late sog expression in the neurogenic ectoderm and the ventral midline of the developing Drosophila embryo, respectively. Here, evidence is presented that the sog primary enhancer also has both activities, with the late enhancer activity dependent on the early activity. Computational analyses showed that the sog primary enhancer contains five Dorsal (Dl)-, four Zelda (Zld)-, three Bicoid (Bcd)-, and no Single-minded (Sim)-binding sites. In contrast to many ventral midline enhancers, the primary enhancer can direct lacZ expression in the ventral midline as well as in the neurogenic ectoderm without a canonical Simbinding site. Intriguingly, the impaired transcriptional synergy between Dl and either Zld or Bcd led to aberrant and abolished lacZ expression in the neurogenic ectoderm and in the ventral midline, respectively. These findings suggest that the two enhancer activities of the sog primary enhancer are functionally consolidated and geographically inseparable.

• BMB Reports
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• v.48 no.10
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• pp.589-594
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• 2015

The shadow enhancer of the short gastrulation (sog) gene directs its sequential expression in the neurogenic ectoderm and the ventral midline of the developing Drosophila embryo. Here, we characterize three unusual features of the shadow enhancer midline activity. First, the minimal regions for the two different enhancer activities exhibit high overlap within the shadow enhancer, meaning that one developmental enhancer possesses dual enhancer activities. Second, the midline enhancer activity relies on five Single-minded (Sim)-binding sites, two of which have not been found in any Sim target enhancers. Finally, two linked Dorsal (Dl)- and Zelda (Zld)-binding sites, critical for the neurogenic ectoderm enhancer activity, are also required for the midline enhancer activity. These results suggest that early activation by Dl and Zld may facilitate late activation via the noncanonical sites occupied by Sim. We discuss a model for Zld as a pioneer factor and speculate its role in midline enhancer activity.

• Journal of Embryo Transfer
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• v.6 no.2
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• pp.30-36
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• 1991

The method of vitnilcation has various merits. It needs neither seeding nor slow freezing. It can freeze embryo by putting it directly into liquid nitrogen at the indoor temperature to $0^{\circ}C$. The operation process is quite easy. Moreover, higher promise of survival can be expected as there is no physical damage by any lumps of ice with the exception of cells. In Kasal's experiment (1990) using EFS liquid and Kang's experiment (1991) using GFS liquid the ratio of the damaged embryo was only 2-3%. But, the method of vitrification is now on the process of improvement, and the final or united method is not yet established. At the present time, most of the major institutes all over the world are using the traditional freezing method in the preservation of mouse embryo, but it is very likely that the vitrification will prevaIl in the near future considering the various merits of it. Calves can be begotten from the embryo by means of vitriilcated preservation in the cases of cow, rat, and rabbit as well as of mouse. In addition, recent experiments have shown that vitrificated preservation was successful in the case of drosophila embryo which was much bigger than mammalian embryo, which fact tells that this method is expected to be preferably used even in the preservation of living organs in the near future.

• Journal of Life Science
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• v.21 no.5
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• pp.621-626
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• 2011

AMP-activated protein kinase (AMPK), a heterotrimeric complex comprising a catalytic ${\alpha}$ subunit and regulatory ${\beta}$ and ${\gamma}$ subunits, has been primarily studied as a major metabolic regulator in various organisms, but recent genetic studies discover its novel physiological functions. The first animal model with no functional AMPK ${\gamma}$ subunit gene was generated by using Drosophila genetics. AMPK ${\gamma}$ flies demonstrated lethality with severe defects in cuticle formation. Further histological analysis found that deletion of AMPK ${\gamma}$ causes severe defects in cell polarity in embryo epithelia. The phosphorylation of nonmuscle myosin regulatory light chain (MRLC), a critical regulator of epithelial cell polarity, was also diminished in AMPK ${\gamma}$ embryo epithelia. These defects in AMPK ${\gamma}$ mutant epithelia were successfully restored by over-expression of AMPK ${\gamma}$. Collectively, these results suggested that AMPK ${\gamma}$ is a critical cell polarity regulator in metazoan development.