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Brodu V.,French National Center for Scientific Research | Baffet A.D.,French National Center for Scientific Research | Le Droguen P.-M.,French National Center for Scientific Research | Casanova J.,Institute Of Biologia Molecular Of Barcelona Csic | And 2 more authors.
Developmental Cell | Year: 2010

Microtubules (MTs) are essential for many cell features, such as polarity, motility, shape, and vesicle trafficking. Therefore, in a multicellular organism, their organization differs between cell types and during development; however, the control of this process remains elusive. Here, we show that during Drosophila tracheal morphogenesis, MT reorganization is coupled to relocalization of the microtubule organizing centers (MTOC) components from the centrosome to the apical cell domain from where MTs then grow. We reveal that this process is controlled by the trachealess patterning gene in a two-step mechanism. MTOC components are first released from the centrosome by the activity of the MT-severing protein Spastin, and then anchored apically through the transmembrane protein Piopio. We further show that these changes are essential for tracheal development, thus stressing the functional relevance of MT reorganization for morphogenesis. © 2010 Elsevier Inc. Source

Fonfria-Subiros E.,Polytechnic University of Catalonia | Acosta-Reyes F.,Polytechnic University of Catalonia | Saperas N.,Polytechnic University of Catalonia | Pous J.,Institute Of Recerca Biomedica Of Barcelona | And 2 more authors.
PLoS ONE | Year: 2012

We present here for the first time the crystal structure of an AT-hook domain. We show the structure of an AT-hook of the ubiquitous nuclear protein HMGA1, combined with the oligonucleotide d(CGAATTAATTCG)2, which has two potential AATT interacting groups. Interaction with only one of them is found. The structure presents analogies and significant differences with previous NMR studies: the AT-hook forms hydrogen bonds between main-chain NH groups and thymines in the minor groove, DNA is bent and the minor groove is widened. © 2012 Fonfría-Subirós et al. Source

Rojas-Cervellera V.,Computer Simulation and Modeling Laboratory | Rojas-Cervellera V.,Institute Of Quimica Teorica I Computacional | Rojas-Cervellera V.,University of Barcelona | Giralt E.,Institute Of Recerca Biomedica Of Barcelona | And 5 more authors.
Inorganic Chemistry | Year: 2012

Recent structural determinations have shown that thiolate-protected gold nanoparticles are not as regular and symmetric as initially thought, but characteristic substructures (staple motifs) are formed on their surface. However, their mechanism of formation, especially the fate of the sulfur protons upon thiol binding, remains one of the most intriguing unanswered questions in gold cluster chemistry. By means of ab initio molecular dynamics (AIMD), we monitor the trajectory of thiol protons reacting with a gold cluster, demonstrating that the staple motif forms in a multiple-pathway chemical reaction, releasing molecular hydrogen. The results obtained also reconcile the conclusions of structural determinations with the interpretations of spectroscopic experiments on solution, suggesting the presence of intact thiols or chemisorbed hydrogen. © 2012 American Chemical Society. Source

Djabrayan N.J.-V.,Institute Of Biologia Molecular Of Barcelona Csic | Djabrayan N.J.-V.,Institute Of Recerca Biomedica Of Barcelona | Cruz J.,Institute Of Biologia Molecular Of Barcelona Csic | Cruz J.,Institute Of Biologia Evolutiva Csic Upf | And 5 more authors.
Cell Reports | Year: 2014

A population of Drosophila adult tracheal progenitor cells arises from differentiated cells of the larval main trachea that retain the ability to reenter the cell cycle and give rise to the multiple adult tracheal cell types. These progenitors are unique to the second tracheal metamere as homologous cells from other segments, express fizzy-related (fzr), the Drosophila homolog of CDH1 protein of the APC complex, and enter endocycle and do not contribute to adult trachea. Here, we examine the mechanisms for their quiescence and show that they reenter the cell cycle by expression of string/cdc25 through ecdysone. Furthermore, we show that preventing endocycle entry is both necessary and sufficient for these tracheal cells to exhibit markers of adult progenitors, thus modifying their genetic program. Finally, we show that Hox-mediated regulation of fzr expression is responsible for progenitor identity and thus specifies a group of differentiated cells with facultative stem cell features. © 2014 The Authors. Source

Campbell K.,Institute Of Biologia Molecular Of Barcelona Csic | Campbell K.,Institute Of Recerca Biomedica Of Barcelona | Casanova J.,Institute Of Biologia Molecular Of Barcelona Csic | Casanova J.,Institute Of Recerca Biomedica Of Barcelona
Nature Communications | Year: 2015

Collective cell migration is a key process underlying the morphogenesis of many organs as well as tumour invasion, which very often involves heterogeneous cell populations. Here we investigated how such populations can migrate cohesively in the Drosophila posterior midgut, comprised of epithelial and mesenchymal cells and show a novel role for the epithelial adhesion molecule E-cadherin (E-Cad) in mesenchymal cells. Despite a lack of junctions at the ultrastructure level, reducing E-Cad levels causes mesenchymal cells to detach from one another and from neighbouring epithelial cells; as a result, coordination between the two populations is lost. Moreover, Bazooka and recycling mechanisms are also required for E-Cad accumulation in mesenchymal cells. These results indicate an active role for E-Cad in mediating cohesive and ordered migration of non-epithelial cells, and discount the notion of E-Cad as just an epithelial feature that has to be switched off to enable migration of mesenchymal cells. © 2015 Macmillan Publishers Limited. All rights reserved. Source

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