Genetic basis of limb and gut development and dysmorphogenesis

Lead Research Organisation: MRC Human Genetics Unit

Abstract

Aberrant organ development leads to human congenital abnormalities. We are investigating the processes of normal organ development and attempting to uncover the events that go wrong resulting in birth defects. One field of interest is the development of the limbs. Each year a large number of infants are born with defects of the arms and/or legs and we are studying a subset which manifest extra fingers and toes. We have identified the genetic mutations that constitute the molecular basis for the defect and propose to investigate how these mutations give rise to hands and feet abnormalities. A second interest is in the region of the viscera that includes the stomach, pancreas, spleen and small intestine. These organs are under strict left/right instructions to grow to one side of the body cavity. When the process of left/right patterning is disrupted a number of abnormalities occur including cardiac and gastrointestinal defects and often congenital loss of the spleen. We propose to study the processes that control the genesis and the placement of these organs.

Technical Summary

Mouse model systems provide insights into the process of organ development. The goals of these studies are to examine mouse mutants that model congenital abnormalities in order to understand both the normal processes that are responsible for organogenesis and the abnormalities that disrupt development and lead to disease.||Focusing on the genetics of the mouse, we examine two aspects of development. Firstly, we explore the mechanisms essential for normal skeletal development. In particular, we investigate limb patterning mechanisms required to generating the array of skeletal elements that constitute the mammalian limb. Expression of the Shh gene is central to the mechanism that patterns the limb. Correct spatio-specific Shh expression is required for normal patterning of the digits. We investigate the mechanisms for the long-range spatiotemporal regulation of Shh and the mechanism by which point mutations residing in the regulator manifests PPD (preaxial polydactyly). We propose to identify sequence elements which may interact with the ZRS and attempt to establish factors required for regulating expression through the ZRS. In addition we propose to use the ZRS as a tool to explore the molecular mechanisms required for patterning the mammalian limb.||Secondly, we investigate the development of the gut; in particular, mechanisms that define the left-right asymmetry of organ systems. One aspect is to focus on the spleno-pancreatic region. These studies give insights into mesodermal/ endodermal interactions important for directing early gut development. We have hypothesized that the splanchnic mesoderm-derived SMP, by coordinating mesenchymal functions, plays a role in the morphogenesis of the gut region which includes the stomach, duodenum, pylorus, and pancreas. The Bapx1 gene resides near or at the top of a hierarchy of genes that controls morphogenesis in this region. The mesenchyme in which these genes are expressed is crucial in sending morphogenetic signals to the endoderm. The mesenchyme specifically grows to the left under the control of the SMP which itself is controlled by the L/R signalling cascade. We plan to investigate the mesenchymal signals regulated by BAPX1 that signal to the endoderm to define the stomach/duodenal boundary, and regulate the rate of cell division. We also plan to investigate the Bapx1 role that is crucial later in development to define an important boundary between the spleen and pancreas. In the absence of this boundary differentiated pancreatic acini are induced to transform to ectopic gut-like structures.||Finally, we have made a mouse model for the Matthew Woods syndrome (or PDAC syndrome) which effects heart asymmetry, lung and visceral development and patients that survive are mentally retarded. The mutation affects retinoic acid signalling and we are investigating the role of the gene on development.

Publications

10 25 50
 
Description Masters Programme
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
Impact Developed Masters by research programme for Edinburgh University
 
Description BSDB-Company of Biologist Travel Award/Company of Biologists
Amount £400 (GBP)
Organisation Company of Biologists 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2010 
End 03/2010
 
Description MRC Student Supplementary Fund
Amount £2,400 (GBP)
Organisation Medical Research Council (MRC) 
Sector Public
Country United Kingdom
Start 02/2016 
End 02/2016
 
Description Wellcome Trust Project Grant
Amount £338,610 (GBP)
Organisation Wellcome Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 01/2009 
End 10/2012
 
Title Aicardi-Goutieres Mouse 
Description Mouse model for Aicardi-Goutieres Syndrome 
Type Of Material Model of mechanisms or symptoms - mammalian in vivo 
Year Produced 2009 
Provided To Others? Yes  
Impact Understanding of the basis for brain autoimmune disease 
 
Title Bapx1 mouse 
Description An animal model (Bapx1 knock-out) for the congenital abnormality called oculo-auriculo-vertebral spectrum. 
Type Of Material Model of mechanisms or symptoms - human 
Year Produced 2006 
Provided To Others? Yes  
Impact Led to significant insights into chondrocyte and vertebral development and left/right asymmetry determination in the gut . Important in understanding the allelic expression imbalance in OAVS 
 
Title Limb abnormality screen 
Description identified genetic basis for preaxial polydactyly and established assay for diagnosis. 
Type Of Material Technology assay or reagent 
Year Produced 2006 
Provided To Others? Yes  
Impact A better understanding of the mechanism for this abnormality. Also provides information for genetic counseling 
 
Title Mice with chromosome 5 engineered 
Description Serial deletions of large region of Chromosome 5 that include the Shh locus 
Type Of Material Model of mechanisms or symptoms - mammalian in vivo 
Provided To Others? No  
Impact Gain insight into developmental regulation of brain, limb and gut 
 
Title Model for studying the human condition holoprosencephaly 
Description A regulatory mutations that lowers the expression of the sonic hedgehog 
Type Of Material Model of mechanisms or symptoms - human 
Year Produced 2017 
Provided To Others? No  
Impact These findings will be published in the upcoming year 
 
Title Skeletal Changes 
Description Modification of skeletal development by creating a series of mutations using the CRISPR/Cas genome engineering system 
Type Of Material Model of mechanisms or symptoms - mammalian in vivo 
Provided To Others? No  
Impact Manuscript being prepared 
 
Title Stra6 deficient mouse 
Description Deletion of the Stra6 gene from the mouse genome. This gene is involved in retinoic acid metabolism and perhaps signaling. Have now made mutation s in a related gene called Stra6.2 
Type Of Material Model of mechanisms or symptoms - mammalian in vivo 
Year Produced 2010 
Provided To Others? Yes  
Impact This mouse provides insights into retinoid transport and signaling during development and storage in adults. Provides a model for the Matthew Woods Syndrome (also called PDAC syndrome). 
 
Title limb cell lines 
Description A cohort of immortalised cell lines from developing limb tissues. New lines now contain a fluorescent marker for Shh expression for genetic screens 
Type Of Material Cell line 
Year Produced 2010 
Provided To Others? Yes  
Impact These lines have provided deeper insights into limb development and Shh signaling. 
 
Title osteoarthritis model 
Description A mouse mutations that results in osteoarthritis that shows a novel pathway responsible for joint inflammation and deformation 
Type Of Material Model of mechanisms or symptoms - human 
Provided To Others? No  
Impact A better understanding of the molecular mechanism responsible for osteoarthritis 
 
Description Acardi-Goutieres Syndrome 
Organisation Medical Research Council (MRC)
Department MRC Human Genetics Unit
Country United Kingdom 
Sector Academic/University 
PI Contribution Provided specialised methodology and intellectual input
Collaborator Contribution Has provided mutation data and phenotypic analyses
Impact Generated a mouse model for Aicardi-Goutieres Syndrome
Start Year 2007
 
Description Corneal development 
Organisation University of Edinburgh
Department Centre for Integrative Physiology
Country United Kingdom 
Sector Academic/University 
PI Contribution Contribute experimental information and advice to students and Postdoc.
Collaborator Contribution Contribute experimental information and data
Impact 19387074 doi.org/10.1016/j.scr.2015.10.016 doi.org/10.1016/j.exer.2016.05.021
 
Description Embryonic growth and patterning 
Organisation Medical Research Council (MRC)
Department MRC Human Genetics Unit
Country United Kingdom 
Sector Academic/University 
PI Contribution Meier Gorlin Syndrome has been identified in patients and we made a genetic model to further probe the molecular disease mechanism Mouse model for analyzing cell proliferation and pattern formation in limb development
Collaborator Contribution Provides a genetic means to determine growth rate on organogensis. Also brought in a student to work collaboratively on the project
Impact A mouse model for the Meier-Gorlin (primitive dwarfism) syndrome.
Start Year 2011
 
Description Innate immunity 
Organisation Medical Research Council (MRC)
Department MRC Human Genetics Unit
Country United Kingdom 
Sector Academic/University 
PI Contribution Provided specialised methodology and intellectual input
Collaborator Contribution provided basic immunology data to advance our understanding of the innate immune system
Impact Generated a number of mouse mutations which affect the innate immunity system
 
Description Long-Range Regulation 
Organisation Medical Research Council (MRC)
Department MRC Human Genetics Unit
Country United Kingdom 
Sector Academic/University 
PI Contribution expertise, intellectual input,access to data,
Collaborator Contribution expertise, intellectual input
Impact Multidisciplinary. Two manuscripts in preparation doi: 10.1242/dev.139188
Start Year 2015
 
Description Matthew wood Syndrome 
Organisation Medical Research Council (MRC)
Department MRC Human Genetics Unit
Country United Kingdom 
Sector Academic/University 
PI Contribution Provided specialised methodology and intellectual input
Collaborator Contribution Provided studentship and patient data
Impact Analysis of genetic models (mouse and zebrafish) to understand retinoic acid involvement in Matthew Wood (PDAC) syndrome
Start Year 2008
 
Description Preaxial Polydactyly Patients 
Organisation Medical Research Council (MRC)
Department MRC Human Genetics Unit
Country United Kingdom 
Sector Academic/University 
PI Contribution Sharing patient information
Collaborator Contribution Sharing information on patientsProvided patient data
Impact 18463159
Start Year 2007
 
Description Preaxial Polydactyly Patients 
Organisation University of Oxford
Department Weatherall Institute of Molecular Medicine (WIMM)
Country United Kingdom 
Sector Academic/University 
PI Contribution Sharing patient information
Collaborator Contribution Sharing information on patientsProvided patient data
Impact 18463159
Start Year 2007
 
Description Syndactyly 
Organisation Medical Research Council (MRC)
Department MRC Human Genetics Unit
Country United Kingdom 
Sector Academic/University 
PI Contribution Chromosomal analysis and molecular biological data
Collaborator Contribution Provided patient data and phenotype analysis and chromosomal analysis
Impact Generated an animal model for human syndactylism DOI:10.1002/humu.21615
Start Year 2006
 
Description Syndactyly 
Organisation Royal Liverpool and Broadgreen University Hospitals NHS Trust
Department Royal Liverpool Children's Hospital
Country United Kingdom 
Sector Hospitals 
PI Contribution Chromosomal analysis and molecular biological data
Collaborator Contribution Provided patient data and phenotype analysis and chromosomal analysis
Impact Generated an animal model for human syndactylism DOI:10.1002/humu.21615
Start Year 2006
 
Description UBR5 
Organisation Cancer Research UK
Department Edinburgh Cancer Research UK Centre
Country United Kingdom 
Sector Academic/University 
PI Contribution Intellectual input, experimental resources and technical assistance
Collaborator Contribution Studentship
Impact Collaborative studentship doi:10.1371/journal.pone.0157079
Start Year 2009
 
Description Wt1 
Organisation Medical Research Council (MRC)
Department MRC Human Genetics Unit
Country United Kingdom 
Sector Academic/University 
PI Contribution Provided specialised methodology and intellectual input
Collaborator Contribution Basic biochemistry analysis
Impact Multidisciplinary (mouse genetics and Biochemistry) doi:10.1038/ng.494
Start Year 2006
 
Description evolution of Shh 
Organisation University of Cape Town
Department Department of Zoology
Country South Africa 
Sector Academic/University 
PI Contribution Functional analysis of Shh in mammalian flight
Collaborator Contribution Initial identification of element
Impact Manuscript in prepaation
Start Year 2012
 
Description CRUK-Public Outreach 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Outreach to the general public to informa and engage on cancer research
Year(s) Of Engagement Activity 2014
 
Description Cat Fancier Magazine 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Wrote an article about genetics and how this has informed on veternary medicine particularly cats

A magazine article
Year(s) Of Engagement Activity Pre-2006,2008
 
Description Interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Media (as a channel to the public)
Results and Impact Interview for podcast (Naked Geneticist) and a book chapter
Year(s) Of Engagement Activity 2015
 
Description MRC Open Day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Demonstrations to 50 high School pupils

None as yet
Year(s) Of Engagement Activity 2010
 
Description National Geographic Interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interviewed by the director of a National Geographic TV program on Genetics

Not Measurable
Year(s) Of Engagement Activity Pre-2006,2008
 
Description Royal Society Partnership Grant--Portree High School 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach Local
Primary Audience Schools
Results and Impact 40 pupils attended presentation on Genetics and practical demonstrations

Practical activities designed now in use across the Highlands and Islands
Year(s) Of Engagement Activity 2010
 
Description Scholastic reader 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Article for a weekly reader in the american schools

None measurable
Year(s) Of Engagement Activity 2006
 
Description School Visit-Plockton 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach Local
Primary Audience Schools
Results and Impact High school activities discussing and demonstrating concepts in Genetics and Evolution

Invited to return for second year
Year(s) Of Engagement Activity 2009
 
Description Science Festival 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact approximately 100 people from the public attended

Resulted in furtherinvitations to address the general public
Year(s) Of Engagement Activity 2011
 
Description Science Festival 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Demonstrating MRC activities to the general public

None that are measurable
Year(s) Of Engagement Activity 2008,2009,2010