Intercellular signalling, cell fate and cell shape in the Drosophila pupal wing

The morphogenesis of tissues in animal development is orchestrated by intercellular signalling and executed by cell behaviours such as changes to shape. Understanding the link between signalling and cell shape changes is a key task of developmental biology. This work addresses this problem using the development of the pupal wing of Drosophila melanogaster. The pupal wing is a bilayered epithelium which is patterned into vein and intervein domains, and which secretes the cuticle of the adult wing. I first address the cellular basis of pupal wing development, and show that the process comprises a series of dynamic cell shape changes involving alterations to the apical and basolateral surfaces of the cells. Using temporally controlled mis-expression, I then investigate the role of intercellular signalling in these shape changes, and define the competence of cells in the wing to respond to ectopic signals. The dimensions of signalling in the pupal wing are then investigated, and I show that while BMP ligands can travel between the layers to promote vein development, such signalling is not a prerequisite for cellular differentiation. Within the plane of the epithelium, the BMP ligand Dpp can only induce signalling at a short range, potentially due to the upregulation of receptor levels in receiving cells. Finally, attention is turned to the means by which cell signalling controls cell shape changes, specifically in the crossveins. I identify the RhoGAP Cv-c as a downstream target of BMP signalling which acts to inhibit a novel RhoGTPase function in intervein development. This provides an example of how signalling pathways can enact cell shape changes, via the transcriptional regulation of RhoGAP

A classification of spherically symmetric spacetimes

A complete classification of locally spherically symmetric four-dimensional Lorentzian spacetimes is given in terms of their local conformal symmetries. The general solution is given in terms of canonical metric types and the associated conformal Lie algebras. The analysis is based upon the local conformal decomposition into 2+2 reducible spacetimes and the Petrov type. A variety of physically meaningful example spacetimes are discussed

Killing tensors in pp-wave spacetimes

The formal solution of the second order Killing tensor equations for the general pp-wave spacetime is given. The Killing tensor equations are integrated fully for some specific pp-wave spacetimes. In particular, the complete solution is given for the conformally flat plane wave spacetimes and we find that irreducible Killing tensors arise for specific classes. The maximum number of independent irreducible Killing tensors admitted by a conformally flat plane wave spacetime is shown to be six. It is shown that every pp-wave spacetime that admits an homothety will admit a Killing tensor of Koutras type and, with the exception of the singular scale-invariant plane wave spacetimes, this Killing tensor is irreducible.Comment: 18 page

Intercellular signalling, cell fate and cell shape in the Drosophila pupal wing

The morphogenesis of tissues in animal development is orchestrated by intercellular signalling and executed by cell behaviours such as changes to shape. Understanding the link between signalling and cell shape changes is a key task of developmental biology. This work addresses this problem using the development of the pupal wing of Drosophila melanogaster. The pupal wing is a bilayered epithelium which is patterned into vein and intervein domains, and which secretes the cuticle of the adult wing. I first address the cellular basis of pupal wing development, and show that the process comprises a series of dynamic cell shape changes involving alterations to the apical and basolateral surfaces of the cells. Using temporally controlled mis-expression, I then investigate the role of intercellular signalling in these shape changes, and define the competence of cells in the wing to respond to ectopic signals. The dimensions of signalling in the pupal wing are then investigated, and I show that while BMP ligands can travel between the layers to promote vein development, such signalling is not a prerequisite for cellular differentiation. Within the plane of the epithelium, the BMP ligand Dpp can only induce signalling at a short range, potentially due to the upregulation of receptor levels in receiving cells. Finally, attention is turned to the means by which cell signalling controls cell shape changes, specifically in the crossveins. I identify the RhoGAP Cv-c as a downstream target of BMP signalling which acts to inhibit a novel RhoGTPase function in intervein development. This provides an example of how signalling pathways can enact cell shape changes, via the transcriptional regulation of RhoGAPs

Key attributes of successful research institutes.

Acknowledgements: We thank Genevieve Almouzni (Institut Curie), Mary Barlow (EMBL-EBI), Monica Bettencourt-Dias (Instituto Gulbenkian de Ciência), Ansgar Büschges (University of Cologne), Hwai-Jong Cheng (IMB, Academia Sinica), Martin Dougherty (Wellcome Sanger Institute), Eugenio Fava (DZNE), Yukiko Goda (RIKEN), Ilona Grunwald Kadow (University of Bonn), Muzlifah Haniffa (Wellcome Sanger Institute), Sabine Helling-Moegen (DZNE), Reinhard Jahn (Max Planck Institute for Multidisciplinary Sciences), Sarah Jewell (DZNE), Yishi Jin (UCSD), Lizzy Langley (Wellcome Sanger Institute), Cheng-Chang Lien (National Yang Ming Chiao Tung University), Pierluigi Nicotera (DZNE), Steve Palmer (Wellcome Sanger Institute), Maggie Payne (Wellcome Sanger Institute), Mike Stratton (Wellcome Sanger Institute), Gaia Tavosanis (University of Aachen), Ron Vale (UCSF), and Dagmar Wachten (University of Bonn) for reading and discussion. We thank Christina Usher for the figure illustration.Science does not take place in a vacuum: The physical and social workplace has a profound influence on scientific discoveries. Everyone at a research institute can contribute to its scientific output and productivity, from faculty research groups to facilities and platforms staff to administration and corporate services. Although the researchers addressing exciting scientific questions are key, their efforts can be fostered and directed by the overarching strategy of the institute, interconnection with facilities and platforms, and strong and directed support of the administration and corporate services. Everybody counts and everybody should be empowered to contribute. But what are the characteristics that make scientific organizations and their people flourish? This Essay looks at the structure and culture of successful research institutes, laying out different operational strategies and highlighting points that need be taken into consideration during their implementation

Key attributes of successful research institutes

Science does not take place in a vacuum: The physical and social workplace has a profound influence on scientific discoveries. Everyone at a research institute can contribute to its scientific output and productivity, from faculty research groups to facilities and platforms staff to administration and corporate services. Although the researchers addressing exciting scientific questions are key, their efforts can be fostered and directed by the overarching strategy of the institute, interconnection with facilities and platforms, and strong and directed support of the administration and corporate services. Everybody counts and everybody should be empowered to contribute. But what are the characteristics that make scientific organizations and their people flourish? This Essay looks at the structure and culture of successful research institutes, laying out different operational strategies and highlighting points that need be taken into consideration during their implementation. What are the features that make a research institute and its people flourish? This Essay explores the organization and culture of successful research institutes and looks at the lessons that can be learned from them

Key attributes of successful research institutes.

Science does not take place in a vacuum: The physical and social workplace has a profound influence on scientific discoveries. Everyone at a research institute can contribute to its scientific output and productivity, from faculty research groups to facilities and platforms staff to administration and corporate services. Although the researchers addressing exciting scientific questions are key, their efforts can be fostered and directed by the overarching strategy of the institute, interconnection with facilities and platforms, and strong and directed support of the administration and corporate services. Everybody counts and everybody should be empowered to contribute. But what are the characteristics that make scientific organizations and their people flourish? This Essay looks at the structure and culture of successful research institutes, laying out different operational strategies and highlighting points that need be taken into consideration during their implementation

Key attributes of successful research institutes.

Science does not take place in a vacuum: The physical and social workplace has a profound influence on scientific discoveries. Everyone at a research institute can contribute to its scientific output and productivity, from faculty research groups to facilities and platforms staff to administration and corporate services. Although the researchers addressing exciting scientific questions are key, their efforts can be fostered and directed by the overarching strategy of the institute, interconnection with facilities and platforms, and strong and directed support of the administration and corporate services. Everybody counts and everybody should be empowered to contribute. But what are the characteristics that make scientific organizations and their people flourish? This Essay looks at the structure and culture of successful research institutes, laying out different operational strategies and highlighting points that need be taken into consideration during their implementation

Targeted action to increase inclusion at the Wellcome Sanger Institute

The Sanger Excellence Fellowship has been established to increase the representation of researchers with Black-heritage backgrounds at a leading research centre in the UK