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- Cinege, G., et al.
(author)
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Genes encoding cuticular proteins are components of the Nimrod gene cluster in Drosophila
- 2017
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In: Insect Biochemistry and Molecular Biology. - : Elsevier BV. - 0965-1748 .- 1879-0240. ; 87, s. 45-54
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Journal article (peer-reviewed)abstract
- The Nimrod gene cluster, located on the second chromosome of Drosophila melanogaster, is the largest synthenic unit of the Drosophila genome. Nimrod genes show blood cell specific expression and code for phagocytosis receptors that play a major role in fruit fly innate immune functions. We previously identified three homologous genes (vajk-1, vajk-2 and vajk-3) located within the Nimrod cluster, which are unrelated to the Nimrod genes, but are homologous to a fourth gene (vajk-4) located outside the cluster. Here we show that, unlike the Nimrod candidates, the Vajk proteins are expressed in cuticular structures of the late embryo and the late pupa, indicating that they contribute to cuticular barrier functions. © 2017 Elsevier Ltd
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- Ejeskär, Katarina, 1969, et al.
(author)
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The Unique Non-Catalytic C-Terminus of P37delta-PI3K Adds Proliferative Properties In Vitro and In Vivo
- 2015
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In: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 10:5
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Journal article (peer-reviewed)abstract
- The PI3K/Akt pathway is central for numerous cellular functions and is frequently deregulated in human cancers. The catalytic subunits of PI3K, p110, are thought to have a potential oncogenic function, and the regulatory subunit p85 exerts tumor suppressor properties. The fruit fly, Drosophila melanogaster, is a highly suitable system to investigate PI3K signaling, expressing one catalytic, Dp110, and one regulatory subunit, Dp60, and both show strong homology with the human PI3K proteins p110 and p85. We recently showed that p37 delta, an alternatively spliced product of human PI3K p110 delta, displayed strong proliferation-promoting properties despite lacking the catalytic domain completely. Here we functionally evaluate the different domains of human p37 delta in Drosophila. The N-terminal region of Dp110 alone promotes cell proliferation, and we show that the unique C-terminal region of human p37 delta further enhances these proliferative properties, both when expressed in Drosophila, and in human HEK-293 cells. Surprisingly, although the N-terminal region of Dp110 and the C-terminal region of p37 delta both display proliferative effects, over-expression of full length Dp110 or the N-terminal part of Dp110 decreases survival in Drosophila, whereas the unique C-terminal region of p37 delta prevents this effect. Furthermore, we found that the N-terminal region of the catalytic subunit of PI3K p110, including only the Dp60 (p85)-binding domain and a minor part of the Ras binding domain, rescues phenotypes with severely impaired development caused by Dp60 over-expression in Drosophila, possibly by regulating the levels of Dp60, and also by increasing the levels of phosphorylated Akt. Our results indicate a novel kinase-independent function of the PI3K catalytic subunit.
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- Syed, Zulfeqhar Ali, et al.
(author)
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A Luminal Glycoprotein Drives Dose-Dependent Diameter Expansion of the Drosophila melanogaster Hindgut Tube
- 2012
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In: Plos Genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 8:8
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Journal article (peer-reviewed)abstract
- An important step in epithelial organ development is size maturation of the organ lumen to attain correct dimensions. Here we show that the regulated expression of Tenectin (Tnc) is critical to shape the Drosophila melanogaster hindgut tube. Tnc is a secreted protein that fills the embryonic hindgut lumen during tube diameter expansion. Inside the lumen, Tnc contributes to detectable O-Glycans and forms a dense striated matrix. Loss of tnc causes a narrow hindgut tube, while Tnc over-expression drives tube dilation in a dose-dependent manner. Cellular analyses show that luminal accumulation of Tnc causes an increase in inner and outer tube diameter, and cell flattening within the tube wall, similar to the effects of a hydrostatic pressure in other systems. When Tnc expression is induced only in cells at one side of the tube wall, Tnc fills the lumen and equally affects all cells at the lumen perimeter, arguing that Tnc acts non-cell-autonomously. Moreover, when Tnc expression is directed to a segment of a tube, its luminal accumulation is restricted to this segment and affects the surrounding cells to promote a corresponding local diameter expansion. These findings suggest that deposition of Tnc into the lumen might contribute to expansion of the lumen volume, and thereby to stretching of the tube wall. Consistent with such an idea, ectopic expression of Tnc in different developing epithelial tubes is sufficient to cause dilation, while epidermal Tnc expression has no effect on morphology. Together, the results show that epithelial tube diameter can be modelled by regulating the levels and pattern of expression of a single luminal glycoprotein.
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