Brown S.D.M.,MRC Mammalian Genetics Unit |
Moore M.W.,International Mouse Phenotyping Consortium
Mammalian Genome | Year: 2012
Determining the function of all mammalian genes remains a major challenge for the biomedical science community in the 21st century. The goal of the International Mouse Phenotyping Consortium (IMPC) over the next 10 years is to undertake broad-based phenotyping of 20,000 mouse genes, providing an unprecedented insight into mammalian gene function. This short article explores the drivers for large-scale mouse phenotyping and provides an overview of the aims and processes involved in IMPC mouse production and phenotyping. © Springer Science+Business Media, LLC 2012.
Chen D.,Beijing Institute of Technology |
Norris D.,MRC Mammalian Genetics Unit |
Ventikos Y.,University College London
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine | Year: 2014
Precise specification of left-right asymmetry is essential for patterning the internal organs of vertebrates. Within the embryonic node, posteriorly polarised cilia rotate, causing a leftward fluid flow (nodal flow) that establishes left-right asymmetry. The mechanism by which an embryo senses nodal flow remains uncertain. Existing hypotheses argue that either nodal flow carries morphogen(s) or lipid-bounded vesicles towards the left, thereby generating an asymmetric signal, and/or that mechano-sensory cilia sense this unidirectional flow, stimulating left-sided intracellular calcium signalling. To date, direct and definitive evidence supporting these hypotheses has been lacking. In this study, we conduct a multiscale study to simulate the nodal cilia and the fluidic environment, analysing left-right signal transmission. By employing computational simulation techniques and solving the relevant three-dimensional unsteady transport equations, we study the flow pattern produced by the rotation of active cilia. By importing dilute species and particles into the computational domain, we investigate the transport of morphogens and nodal vesicular parcels, respectively. Furthermore, by extending the analysis to include the solid mechanics of passive deformable cilia and the coupling of their structural behaviour with the emerging fluid mechanics, we study the response of passive cilia to the nodal flow. Our results reproduce the unidirectional nodal flow, allowing us to evaluate the plausibility of both chemo- and mechano-sensing hypotheses. The quantitative measurements of the flow rate, the molecular transport and distribution provide guidance regarding the necessary morphogen molecular weights to break signalling symmetry. The passive sensory ciliary deformation gives indications regarding the plausibility of this mechano-signalling mechanism. © IMechE 2014.
Hazelwood L.D.,University of Leeds |
Hancock J.M.,MRC Mammalian Genetics Unit |
Hancock J.M.,University of Cambridge
BMC Developmental Biology | Year: 2013
Background: Cells in some tissues acquire a polarisation in the plane of the tissue in addition to apical-basal polarity. This polarisation is commonly known as planar cell polarity and has been found to be important in developmental processes, as planar polarity is required to define the in-plane tissue coordinate system at the cellular level. Results: We have built an in-silico functional model of cellular polarisation that includes cellular asymmetry, cell-cell signalling and a response to a global cue. The model has been validated and parameterised against domineering non-autonomous wing hair phenotypes in Drosophila. Conclusions: We have carried out a systematic comparison of in-silico polarity phenotypes with patterns observed in vivo under different genetic manipulations in the wing. This has allowed us to classify the specific functional roles of proteins involved in generating cell polarity, providing new hypotheses about their specific functions, in particular for Pk and Dsh. The predictions from the model allow direct assignment of functional roles of genes from genetic mosaic analysis of Drosophila wings. © 2013 Hazelwood and Hancock; licensee BioMed Central Ltd.
Joyce P.I.,MRC Mammalian Genetics Unit |
Fratta P.,University College London |
Fisher E.M.C.,University College London |
Acevedo-Arozena A.,MRC Mammalian Genetics Unit
Mammalian Genome | Year: 2011
Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease with no cure. Breakthroughs in understanding ALS pathogenesis came with the discovery of dominant mutations in the superoxide dismutase 1 gene (SOD1) and other genes, including the gene encoding transactivating response element DNA binding protein-43 (TDP-43). This has led to the creation of animal models to further our understanding of the disease and identify a number of ALS-causing mechanisms, including mitochondrial dysfunction, protein misfolding and aggregation, oxidative damage, neuronal excitotoxicity, non-cell autonomous effects and neuroinflammation, axonal transport defects, neurotrophin depletion, effects from extracellular mutant SOD1, and aberrant RNA processing. Here we summarise the SOD1 and TDP-43 animal models created to date, report on recent findings supporting the potential mechanisms of ALS pathogenesis, and correlate this understanding with current developments in the clinic. © 2011 Springer Science+Business Media, LLC.
Davis H.,University of Oxford |
Lewis A.,University of Oxford |
Spencer-Dene B.,Cancer Research UK Research Institute |
Tateossian H.,MRC Mammalian Genetics Unit |
And 3 more authors.
Journal of Pathology | Year: 2011
FBXW7 is the substrate recognition component of a SCF-type E3 ubiquitin ligase. It has multiple targets such as Notch1, c-Jun, and cyclin E that function in critical developmental and signalling pathways. Mutations in FBXW7 are often found in many types of cancer. In most cases, these mutations do not inactivate the protein, but are mono-allelic missense changes at specific arginine resides involved in substrate binding. We have hypothesized that FBXW7 mutations are selected in cancers for reasons other than haploinsufficiency or full loss-of-function. Given that the existing mutant Fbxw7 mice carry null alleles, we created a mouse model carrying one of the commonly occurring point mutations (Fbxw7R482Q in the WD40 substrate recognition domain of Fbxw7. Mice heterozygous for this mutation apparently developed normally in utero, died perinatally due to a defect in lung development, and in some cases showed cleft palate and eyelid fusion defects. By comparison, Fbxw7 +/- mice were viable and developed normally. Fbxw7-/- animals died of vascular abnormalities at E10.5. We screened known FBXW7 targets for changes in the lungs of the Fbxw7R482Q/+ mice and found Tgif1 and Klf5 to be up-regulated. Fbxw7R482Q alleles are not functionally equivalent to heterozygous or homozygous null alleles, and we propose that they are selected in tumourigenesis because they cause a selective or partial loss of FBXW7 function. © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Chen D.,University of Oxford |
Norris D.,MRC Mammalian Genetics Unit |
Ventikos Y.,University of Oxford
Medical Engineering and Physics | Year: 2011
Left-right symmetry breaking in the mammalian embryo is believed to occur in a transient embryonic structure, the node: rotational motion of cilia within this structure creates a leftward flow of liquid that is the first asymmetric event observed. A hypothesis, often referred to as the "two-cilia" hypothesis, proposes that the node contains two kinds of primary cilia: motile cilia, driven by motor proteins, that rotate clockwise generating the leftward flow and passive cilia that act as mechano-sensors, reacting mechanically to the emerging flow. The exact mechanism that underlies the initial breaking of symmetry remains unclear, in spite of several studies that have attempted to elucidate the processes involved. In this paper, we present two computational models to (i) simulate the unidirectional flow induced by the active ciliary motion as well as their propulsion on the passive cilia and to (ii) investigate the protein activity that produces the active ciliary rotation-like movement. The models presented incorporate methodologies from computational fluid dynamics, deformable mesh computational techniques and fluid-structure interaction analysis. By solving the three-dimensional unsteady transport equations, with suitable boundary conditions, we confirm that the whirling motion of active cilia is capable of inducing the unidirectional flow and that the passive cilia are pushed by this flow towards the left with a visible deformation of 41.7% of the ciliary length on the tip, supporting the plausibility of the two-cilia hypothesis. Further, by applying finite element analysis and grid deformation techniques, we investigate the ciliary motion triggered by the activation of protein motors and propose a possible dynein activation pattern that is able to produce the clockwise rotation of embryonic cilia. © 2010 IPEM.
Morgan H.,MRC Mammalian Genetics Unit |
Simon M.,MRC Mammalian Genetics Unit |
Mallon A.-M.,MRC Mammalian Genetics Unit
International Review of Neurobiology | Year: 2012
Comprehensive phenotyping through the International Mouse Phenotyping Consortium (IMPC)- www.mousephenotype.org-will reveal the pleiotropic functions of every gene in the mouse genome and uncover the wider role of genetic loci within diverse biological systems. The informatics challenge will be to develop an infrastructure to acquire the diverse and complex data sets generated from broad-based phenotyping and disseminate these data in an integrated manner to the scientific community. We describe here the current methodologies implemented to capture and disseminate these data, and plans within the Knockout Mouse Phenotyping Project (KOMP2) (http://commonfund.nih.gov/KOMP2/)-funded informatics consortium to scale these implementations to manage the surge in data from the IMPC. © 2012 Elsevier Inc.
Agency: GTR | Branch: MRC | Program: | Phase: Intramural | Award Amount: 1.72M | Year: 2012
Our major aim is to identify new genes or genetic pathways involved in neurodegeneration and try to understand how these genetic mutations lead to disease using mouse models. Once a human genetic mutation is identified that is causative for a disorder, the next step in most investigations of disease mechanisms (and therefore in developing therapeutics) is to make mouse models of the genetic disorder, such that we can then investigate every stage of pathogenesis in all tissues. This is critically important for neurodegeneration, where interactions between different neuronal populations and other cells in the brain and spinal cord cannot be recapitulated in vitro. We focus our work mainly on Amyotrophic lateral sclerosis (ALS) and Huntington’s disease (HD). They are both fatal neurodegenerative disorders for which no major treatments exist. The focus of our work is twofold. First, we work on new disease causative genes identified by others and develop new mouse models carrying mutations on those genes with the ultimate aim of understanding how these mutations lead to neurodegeneration at the cellular and molecular level. Second, we identify new genes involved in neurodegeneration in the mouse by using mutagenesis. The mutagenesis consist of mutating genes in the mouse and then study the mutant mice over time for any neurodegenerative disease symptoms, such as muscle weakness or motor disturbances such as tremors or gait abnormalities. All new mouse models identified are made freely available to the scientific community.
Gates H.,MRC Mammalian Genetics Unit |
Mallon A.-M.,MRC Mammalian Genetics Unit |
Brown S.D.M.,MRC Mammalian Genetics Unit
Methods | Year: 2011
Comprehensive phenotyping will be required to reveal the pleiotropic functions of a gene and to uncover the wider role of genetic loci within diverse biological systems. The challenge will be to devise phenotyping approaches to characterise the thousands of mutants that are being generated as part of international efforts to acquire a mutant for every gene in the mouse genome. In order to acquire robust datasets of broad based phenotypes from mouse mutants it is necessary to design and implement pipelines that incorporate standardised phenotyping platforms that are validated across diverse mouse genetics centres or mouse clinics. We describe here the rationale and methodology behind one phenotyping pipeline, EMPReSSslim, that was designed as part of the work of the EUMORPHIA and EUMODIC consortia, and which exemplifies some of the challenges facing large-scale phenotyping. EMPReSSslim captures a broad range of data on diverse biological systems, from biochemical to physiological amongst others. Data capture and dissemination is pivotal to the operation of large-scale phenotyping pipelines, including the definition of parameters integral to each phenotyping test and the associated ontological descriptions. EMPReSSslim data is displayed within the EuroPhenome database, where a variety of tools are available to allow the user to search for interesting biological or clinical phenotypes. © 2011 Elsevier Inc.
Tateossian H.,MRC Mammalian Genetics Unit |
Morse S.,MRC Mammalian Genetics Unit |
Parker A.,MRC Mammalian Genetics Unit |
Mburu P.,MRC Mammalian Genetics Unit |
And 5 more authors.
Human Molecular Genetics | Year: 2013
Otitis media with effusion (OME) is the most common cause of hearing loss in children and tympanostomy to alleviate the condition remains the commonest surgical intervention in children in the developed world. Chronic and recurrent forms of OM are known to have a very significant genetic component, however, until recently little was known of the underlying genes involved. The identification of mouse models of chronic OM has indicated a role of transforming growth factor beta (TGFβ) signalling and its impact on responses to hypoxia in the inflamed middle ear. We have, therefore, investigated the role of TGFβ signalling and identified and characterized a new model of chronic OM carrying a mutation in the gene for transforming growth interacting factor 1 (Tgif1). Tgif1 homozygous mutant mice have significantly raised auditory thresholds due to a conductive deafness arising from a chronic effusion starting at around 3 weeks of age. The OM is accompanied by a significant thickening of the middle ear mucosa lining, expansion of mucin-secreting goblet cell populati ns and raised levels of vascular endothelial growth factor, TNF-α and IL-1β in ear fluids. We also identified downstreameffects on TGFb signalling in middle ear epithelia at the time of development of chronic OM. Both phosphorylated SMAD2 and p21 levels were lowered in the homozygous mutant, demonstrating a suppression of the TGFβ pathway. The identificationand characterization of the Tgif mutant supports the role of TGFβ signalling in the development of chronic OM and proides an important candidate gene for geneticstudies in the human population. © The Author 2013. Published by Oxford University Press.