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David Brook

Professor of Human Genetics, Faculty of Medicine & Health Sciences

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Biography

University of Manchester BSc 1979, University of Edinburgh PhD 1983, University of Wales College of Medicine Post-Doc 1982 - 1989, Massachusetts Institute of Technology Post-Doc 1989 - 1992, University of Nottingham Senior Lecturer 1992 - 1995, Professor 1995 - present, Head of the Institute of Genetics 2000 - 2003, Head of the School of Biology 2003 - 2008.

Teaching Summary

Human Molecular Genetics

Research Summary

Molecular genetic studies to identify genes involved in cardiac development: Holt-Oram syndrome (HOS) is an inherited disorder that affects the development of the heart and upper limb. Whilst HOS is… read more

Current Research

Molecular genetic studies to identify genes involved in cardiac development: Holt-Oram syndrome (HOS) is an inherited disorder that affects the development of the heart and upper limb. Whilst HOS is relatively rare, affecting 1 in 50,000, a better understanding of this condition will provide insights to the more common abnormalities of heart development such as atrial septal defects and ventricular septal defects commonly referred to as hole-in-the-heart, which can affect 1 in 500 newborns. We have identified a gene, TBX5, which when mutated causes Holt-Oram syndrome. We are studying the molecular genetics of TBX5 to identify upstream and downstream genes, and proteins with which it interacts to elucidate its role in cardiac development. We are also studying a series of other families with dominantly inherited atrial septal defects to identify the genetic basis of this condition. In collaboration with colleagues at Leicester Glenfield Hospital, the main pediatric cardiology centre in the region, we are collecting blood samples for DNA analysis from patients with sporadic congenital heart disorders and their relatives. The objective of this work is to determine the genetic contribution to sporadic congenital heart disease.

Downstream Targets of TBX5

To identify downstream targets of Tbx5 we have set up an experimental system using the embryonal carcinoma cell line P19CL6 as a tissue culture model of cardiac differentiation. P19CL6 cells can be differentiated efficiently in culture to form beating cardiomyocytes. The aim of these experiments is to establish a system in which the expression of Tbx5 and other transcription factors can be manipulated in a cell based assay and the downstream effects, in terms of impact on gene expression, monitored using microarrays. This system also provides an additional readout of the cells' phenotype, i.e. their ability to beat.

In order to promote differentiation to form beating cardiomyocytes P19CL6 cells are exposed to DMSO. At day 0 of differentiation ~200-500 cells in 20 m l drops of tissue culture medium containing 0.5% DMSO are pipetted onto a Petri Dish lid and inverted over 20 ml of PBS. 48 hrs later (Day 2), the cells in the hanging drops will have come together to form embryoid bodies (EBs), which are rinsed and placed into fresh medium containing 0.5% DMSO in a non-tissue culture treated Petri dish so that the EBs remain in suspension. On day 5, the EBs are transferred to a tissue culture grade dish containing a MEM and between days 7 to 10 the EBs begin to beat. The proportion of beating cells in each embryoid body varies but a representative set of images is shown below (Arrows highlight regions of beating cells).

References

Li, Q-Y. et al. (1997) Holt-Oram syndrome is caused by mutations in TBX5, a member of the Brachyury (T) gene family. Nature Genetics 15, 21-29.

Cross, S.J., Ching, Y-H., Li, Q-L., Armstrong-Buisseret, L., Spranger, S., Munnich, A., Bonnet, D., Pentinnen, M., Jonveaux, P., Mortier, G., van Ravenswaaij, C., Brook, J.D. and Newbury-Ecob, R. (2000) The mutation spectrum in Holt-Oram syndrome. Journal of Medical Genetics 37, 785-787.

Ghosh, T.K., Packham, E.A., Bonser, A.J., Robinson, T.E., Cross, S.J. and Brook, J.D. (2001) Characterization of the TBX5 binding site and analysis of mutations that cause Holt-Oram syndrome. Human Molecular Genetics 19(18), 1983-1994.

Ching, Y.H., Ghosh, T.K., Cross, S.J., Packham, E.A., Honeyman, L., Loughna, S., Robinson, T.E., Dearlove, A.M., Ribas, G., Bonser, A.J., Thomas, N.R., Scotter, A.J., Caves, L.S., Tyrrell, G.P., Newbury-Ecob, R.A., Munnich, A., Bonnet, D. and Brook, J.D. (2005) Mutation in myosin heavy chain 6 causes atrial septal defect. Nat Genet, 37, 423-428.

Understanding the molecular basis of myotonic dystrophy

Myotonic dystrophy (DM) is the most common form of muscular dystrophy affecting adults. DM is caused by the expansion of a repeated DNA sequence, CTG, which is located in the 3? untranslated region of a gene DMPK. It is not known how the expansion of this repeat causes the pathophysiology of DM. There are two main theories. One possibility is that expansion of the repeat affects the expression of DMPK and neighbouring genes. The other possibility is that the DMPK RNA with an expanded repeat interacts with cellular proteins to produce a gain-of-function mutation. We are actively investigating both possible mechanisms.

References

Hamshere, M.G., Newman, E.E., Alwazzan, M., Athwal, B. and Brook, J.D. (1997) Transcriptional abnormality in myotonic dystrophy affects DMPK but not neighbouring genes. Proc. Natl. Acad. Sci. USA 94, 7394-7399.

Alwazzan, M., Hamshere, M.G., Lennon, G.G. and Brook, J.D. (1998) Six transcripts map within 200 kilobases of the myotonic dystrophy expanded repeat. Mammalian Genome 9, 485-487.

Alwazzan, M., Newman, E., Hamshere, M.G. and Brook, J.D. (1999) Myotonic dystrophy is associated with a reduced level of RNA from the DMWD allele adjacent to the expanded repeat. Human Molecular Genetics 8, 1491-1497.

Fardaei, M., Larkin, K., Brook, J.D. and Hamshere, M.G. (2001) In vivo co-localisation of MBNL, protein with DMPK expanded-repeat transcripts. Nucleic Acids Research 29, 2766-2771.

Fardaei, M., Rogers, M.T., Thorpe, H.M., Larkin, K., Hamshere, M.G., Harper, P.S. and Brook

Future Research

Holt-Oram syndrome (HOS) is an inherited disorder that affects the development of the heart and upper limb. Whilst HOS is relatively rare, affecting 1 in 50,000, a better understanding of this condition will provide insights to the more common abnormalities of heart development such as atrial septal defects and ventricular septal defects commonly referred to as hole-in-the-heart, which can affect 1 in 500 newborns. We have identified a gene, TBX5, which when mutated causes Holt-Oram syndrome. We are studying the molecular genetics of TBX5 to identify upstream and downstream genes, and proteins with which it interacts to illucidate its role in cardiac development. We are also studying a series of other families with dominantly inherited atrial septal defects to identify the genetic basis of this condition.

Centre for Genetics and Genomics

The University of Nottingham
Queen's Medical Centre
Nottingham, NG7 2UH

Tel: +44 (0) 115 823 0354
Fax: +44 (0) 115 823 0338
Email: genetics@nottingham.ac.uk