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Biomedical subjects

Kay Davies

Publications and source records attributed to Kay Davies.

8 recordsLinked to original sources

A functional analysis of mouse models of cardiac disease through metabolic profiling.

Since the completion of the human and mouse genomes, the focus in mammalian biology has been on assessing gene function. Tools are needed for assessing the phenotypes of the many mouse models that are now being generated, where genes have been "knocked out," "knocked in," or mutated, so that gene expression can be understood in its biological context. Metabolic profiling of cardiac tissue through high resolution NMR spectroscopy in conjunction with multivariate statistics has been used to classify mouse models of cardiac disease. The data sets included metabolic profiles from mouse models of Duchenne muscular dystrophy, two models of cardiac arrhythmia, and one of cardiac hypertrophy. The metabolic profiles demonstrate that the strain background is an important component of the global metabolic phenotype of a mouse, providing insight into how a given gene deletion may result in very different responses in diverse populations. Despite these differences associated with strain, multivariate statistics were capable of separating each mouse model from its control strain, demonstrating that metabolic profiles could be generated for each disease. Thus, this approach is a rapid method of phenotyping mouse models of disease.

Animals↗

Survival of motor neuron gene downregulation by RNAi: towards a cell culture model of spinal muscular atrophy.

Gene silencing with double-stranded RNA (RNAi) has proved useful for gene function studies, and should be especially well suited to studying diseases resulting in embryonal lethality where transgenic animal models are difficult to generate. We are applying this approach to the autosomal recessive disease spinal muscular atrophy (SMA). SMA is caused by mutations in the survival of motor neuron gene (SMN). The SMN protein is ubiquitously expressed and plays a role in RNA processing and its reduction in SMA ultimately leads to motor neuron degeneration in the spinal cord. The reasons for this motor neuron selectivity, however, are still unclear. SMN is essential for the viability of most eukaryotic organisms and this has made the generation of animal models of SMA extremely difficult. Here we describe a different approach to study SMN function using RNAi to silence SMN expression in cells. We designed double-stranded small interfering RNA (siRNA) targeted against murine Smn and transfected the murine embryonal terato-carcinoma cell line P19. The siRNAs reduced both Smn RNA and protein levels in the P19 cells compared to controls. These results illustrate that double-stranded RNA can be an effective gene silencing approach even in a protein that is essential for survival and highly expressed, and it could therefore be a valuable tool to study SMN function.

Animals↗

Towards a mutant map of the mouse--new models of neurological, behavioural, deafness, bone, renal and blood disorders.

With the completion of the first draft of the human genome sequence, the next major challenge is assigning function to genes. One approach is genome-wide random chemical mutagenesis, followed by screening for mutant phenotypes of interest and subsequent mapping and identification of the mutated genes in question. We (a consortium made up of GlaxoSmithKline, the MRC Mammalian Genetics Unit and Mouse Genome Centre, Harwell, Imperial College, London, and the Royal London Hospital) have used ENU mutagenesis in the mouse for the rapid generation of novel mutant phenotypes for use as animal models of human disease and for gene function assignment (Nolan et al., 2000). As of 2003, 35,000 mice have been produced to date in a genome-wide screen for dominant mutations and screened using a variety of screening protocols. Nearly 200 mutants have been confirmed as heritable and added to the mouse mutant catalogue and, overall, we can extrapolate that we have recovered over 700 mutants from the screening programme. For further information on the project and details of the data, see http://www.mgu.har.mrc.ac.uk/mutabase.

Animals↗

The European dimension for the mouse genome mutagenesis program.

The European Mouse Mutagenesis Consortium is the European initiative contributing to the international effort on functional annotation of the mouse genome. Its objectives are to establish and integrate mutagenesis platforms, gene expression resources, phenotyping units, storage and distribution centers and bioinformatics resources. The combined efforts will accelerate our understanding of gene function and of human health and disease.

Animals↗

Developing an integrated paediatric low vision service.

A survey of usage of low vision aids (LVAs) by 56 children with visual impairment, who were attending mainstream schools in Wirral, was undertaken. A total of 25% of children owned an LVA and 5% were using these on a regular basis. These low levels of ownership and usage led to the development of a low vision service involving the collaboration of education and health care. This paper describes the development of that service, its elements and implementation. The results from the new service show that of the 29 children issued with an LVA, 82.7% are using them on a regular basis. Having an integrated service is shown to significantly improve LVA usage in the group of children seen so far. The service results are discussed with suggestions for future service development.

Adolescent↗

A study of short utrophin isoforms in mice deficient for full-length utrophin.

Utrophin can functionally replace dystrophin in dystrophin-deficient muscle and may have a role in a therapeutic strategy for Duchenne muscular dystrophy. This has resulted in many investigations of the full-length muscle form of utrophin; however, the short utrophins and non-muscle forms have been relatively neglected, partly because they are difficult to analyze in the presence of the full-length form. Our study circumvents this problem by using mice deficient for the full-length form (UKOex6 mice) to study the translation and distribution of short utrophins. Four tissues were examined-kidney, testis, fetal hands/feet, and brain-and three novel short isoforms were identified, including Up120, which appears to be specific to kidney glomeruli, and Up 109, expressed in the fetal dermis. A third form, Up103, was found in testis but at extremely low levels. A cDNA for Up109 has been isolated and shown to have a unique NH2-terminal sequence. In addition, the first exons of Up109 and another short form, G-utrophin, have both been located within intron 55, 56 kb apart. Our immunological studies show that G-utrophin protein accumulates only in neural tissue, in line with its similarly restricted RNA distribution. Our study of testis expression shows, for the first time, that full-length utrophin is expressed at high levels in Leydig cells, raising the possibility that this protein is involved in testosterone secretion. We note that translation of the short utrophins, especially Up140 and Up71, is relatively inefficient and discuss the significance of this observation.

Amino Acid Sequence↗