1,721,054 research outputs found
Functional analysis of the BMP4 antagonists during Drosophila embryo and wing development
No full textDrosophila 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.open
Nutrient control of Drosophila longevity
No full textDietary restriction (DR) extends the lifespan of many animals, including Drosophila melanogaster. Recent work with flies shows that longevity is controlled by the ratio of consumed protein relative to carbohydrates. Given that reduced insulin and/or insulin-like growth factor (IGF) and target of rapamycin (TOR) signaling increase Drosophila lifespan, these pathways are candidate mediators of DR. However, this idea has ambiguous experimental support. The Nutritional Geometric Framework (NGF), which dissects the impact of nutrient protein relative to carbohydrates, may provide an approach to resolving the roles for these pathways in DR. Nutrient sensing of protein and carbohydrate may occur in the fat body through signals to hypothalamic-like neurons in the fly brain and, thus, control secretion of insulin-like peptides that regulate longevityopen
Molecular mechanism of endoplasmic reticulum stress transducer OASIS family
No full textThe endoplasmic reticulum (ER) in the eukaryotic cells is the first compartment in the secretory
pathway. Almost secretory proteins and membrane proteins are secreted through the ER, in which
post-translational modifications occur via diverse signals from the ER lumen to the cytoplasm and
nucleus. Only then are correctly-folded proteins secreted to the outside cells. Unfolded proteins that
accumulate in the ER cause a kind of intracellular stress, ER stress, and activate an unfolded protein
response (UPR) system. The 3 major transducers of the UPR are inositol requiring 1 (IRE1), PKR-like
ER kinase (PERK) and activating transcription factor 6 (ATF6), all of which are ER transmembrane
proteins. Recently, novel types of a new ATF6 family have been identified. Those commonly have an
ER-transmembrane domain, a transcription-activation domain and a basic leucine zipper (bZIP) domain―
Luman, OASIS, BBF2H7, CREBH and CREB4. Each factor functions by regulating the UPR in
specific organs and tissues. Although the detailed molecular mechanisms of OASIS family members
are unknown, in this study we comprehensively introduce these molecular signals.open
Expression of beta-catenin-interacting protein 1 (CTNNBIP1) gene is increased under hypothermia but decreased under additional ischemia conditions
No full textIt has recently been shown that hypothermia treatment improves brain ischemia injury and is being increasingly
considered by many clinicians. However, the precise roles of hypothermia for brain ischemia are not yet clear. In the
present study we demonstrated firstly that hypothermia induced beta-catenin-interacting protein 1 (CTNNBIP1) gene
expression and its expression was dramatically decreased under ischemic conditions. It was also demonstrated that
hypothermia activated endoplasmic reticulum (ER) stress sensors especially both, the phosphorylation of eIF2α, and
ATF6 proteolytic cleavage. However, the factors of apoptosis and autophagy were not associated with hypothermia.
These findings suggested that hypothermia controlled CTNNBIP1 gene expression under ischemia, which may provide
a clue to the development of treatments and diagnostic methods for brain ischemia.open
Potential role of genetic engineering in pest management
No full textGenetic engineering, which was started by the E. coli gene manipulation, has led to rapid development
in all area of life sciences. Recently, genetic engineering, which is an insertion or a removal technique
of a specific gene on chromosomes, has been established and is usefully available in the applied
life sciences including medicine and agriculture. In this review, we briefly explain pest management
focusing on Release of Insects carrying a Dominant Lethal (RIDL) that is a highly economic and environment-
friendly method of biological pest control. Although at present RIDL confronts many difficulties
in applying directly in fields, it will be one of the best methods for the pest management in
the near future without pesticides and disturbing ecosystem by the continued development of genetic
engineering. However, these powerful techniques must be considered with great care to avoid harm
to ecosystem.open
High fat diet-induced TGF-β/Gbb signaling provokes insulin resistance through the tribbles expression
No full textHyperglycemia, hyperlipidemia, and insulin resistance are hallmarks of obesity-induced type 2 diabetes, which is often caused by a high-fat diet (HFD). However, the molecular mechanisms underlying HFD-induced insulin resistance have not been elucidated in detail. In this study, we established a Drosophila model to investigate the molecular mechanisms of HFD-induced diabetes. HFD model flies recapitulate mammalian diabetic phenotypes including elevated triglyceride and circulating glucose levels, as well as insulin resistance. Expression of glass bottom boat (gbb), a Drosophila homolog of mammalian transforming growth factor-β (TGF-β), is elevated under HFD conditions. Furthermore, overexpression of gbb in the fat body produced obese and insulin-resistant phenotypes similar to those of HFD-fed flies, whereas inhibition of Gbb signaling significantly ameliorated HFD-induced metabolic phenotypes. We also discovered that tribbles, a negative regulator of AKT, is a target gene of Gbb signaling in the fat body. Overexpression of tribbles in flies in the fat body phenocopied the metabolic defects associated with HFD conditions or Gbb overexpression, whereas tribbles knockdown rescued these metabolic phenotypes. These results indicate that HFD-induced TGF-β/Gbb signaling provokes insulin resistance by increasing tribbles expression.open
Short-term hypothermia induces beta-catenin-interacting protein1 gene expression in PC12 cells
No full textThe effects of hypothermic treatment (32℃) on recovery from ischemia are controversial because the precise
mechanisms of hypothermia remain unclear. We demonstrated previously that hypothermia induces beta-catenin-interacting
protein 1 (CTNNBIP1) gene expression in vitro. In this study, we evaluated the effects of various hypothermic conditions,
including lithium chloride treatment, on CTNNBIP1 gene expression. The results show that short-term hypothermic
treatment resulted in relatively higher CTNNBIP1 gene expression than that of a longer treatment. These findings indicate
that hypothermia controls CTNNBIP1 gene expression, which may provide clues to develop treatments to recover from
and diagnose ischemia.open
Luteolin-induced apoptosis through activation of endoplasmic reticulum stress sensors in pheochromocytoma cells
No full textLuteolin [2-(3,4-dihydroxyphenyl)-5,7-dilry-droxy-4-chromenone] is an active flavonoid compound from Lonicera japonica (Caprifoliaceae). Luteolin inhibits tumor cell proliferation, inflammatory and oxidative stress better, when compared with other flavonoids. In the present study, it was demonstrated that luteolin induces typical apoptosis in PC12 cells (derived from a pheochromocytoma of the rat adrenal medulla) accompanied by DNA fragmentation and formation of apoptotic bodies. In addition, luteolin regulates expression of the endoplasmic reticulum (ER) chaperone binding immunoglobulin protein, activating ER stress sensors (eukaryotic initiation factor 2a phosphorylation and X-box binding protein 1 mRNA splicing) and induced autophagy. The results indicated that luteolin induces the upregulation of the unfolded protein response pathway through the ER stress sensors, which helps as an influential regulator for the apoptosis pathway in PC12 cells. The results suggested that the understanding of the molecular mechanisms underlying lute-olin-induced apoptosis may be useful in cancer therapeutics, chemoprevention and neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease.
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