Oxygen Toxicity As A Factor In Retinal Degenerations: Genetic And Environmental Mechanisms
Funder
National Health and Medical Research Council
Funding Amount
$269,250.00
Summary
This project will explore the mechanisms underlying a group of blinding diseases called Retinitis Pigmentosa (RP). They are caused by the death or degneration of the light-receptive cells of the retina of the eye (photoreceptors). It is well established that many forms of RP are caused by genetic mutations but many cases (40-50%) occur 'sporadically', i.e. without a family history. Further there is growing evidence that the rate at which genetic forms of the disease progress is strongly influenc ....This project will explore the mechanisms underlying a group of blinding diseases called Retinitis Pigmentosa (RP). They are caused by the death or degneration of the light-receptive cells of the retina of the eye (photoreceptors). It is well established that many forms of RP are caused by genetic mutations but many cases (40-50%) occur 'sporadically', i.e. without a family history. Further there is growing evidence that the rate at which genetic forms of the disease progress is strongly influenced by environmental factors, particularly light and oxygen. To analyse how these environmental factors affect the stability of the retina, we will use a range of techniques (including gene array technology) to study the molecular events which link light or oxygen stress to photoreceptor death. The work will be done in mouse 'models' of the disease. It is increasingly well established that the rodent (rat and mouse) retina and human retina share a basic structure and functional detail. These models allow intensive investigation, with results which are directly applicable to human disease. Our principal emphasis will be on three aspects of these models: (1) the molecular mechanisms induced in the retina by light stress or oxygen stress; (2) the role of mitochondria (cellular organelles essential for both cell metabolism and cell stability; and (3) genes which regulate the vulnerability of photoreceptors to oxygen stress. RP has been recognised for nearly 100 years as a leading cause of blindness in young adults. It is usually diagnosed in the young adult as a failure of night vision, but the prognosis is grim (relentlessly progressive loss of vision), and there is still no effective treatment. The work proposed will contribute to our understanding of the basic mechanisms involved, and will explore some approaches to therapy for, or at least to mitigation of the blindness of RP.Read moreRead less
Studies in humans and model organisms have shown that defects in centromere function result in chromosome abnormalities and copy-number changes that constitute a major cause of aneuploid-related syndromic disorders, intellectual disability, infertility, pregnancy loss, and cancer. Understanding the biological properties and functions of the centromere is therefore a high priority for health research.
Chromosomes are structures that carry genes in all our cells. Every human cell has 46 chromosomes. In the nucleus of eukaryotic cells, DNA is highly folded and compacted with specific proteins into a dynamic polymer called chromatin. Gene expression, chromosome division, DNA replication, and repair all act, not on DNA alone, but on this chromatin template. The discovery that enzymes can (re)organise chromatin into accessible and inaccessible configurations revealed mechanisms that considerably e ....Chromosomes are structures that carry genes in all our cells. Every human cell has 46 chromosomes. In the nucleus of eukaryotic cells, DNA is highly folded and compacted with specific proteins into a dynamic polymer called chromatin. Gene expression, chromosome division, DNA replication, and repair all act, not on DNA alone, but on this chromatin template. The discovery that enzymes can (re)organise chromatin into accessible and inaccessible configurations revealed mechanisms that considerably extend the information potential of the genetic code. In addition, it is now established that chromatin structural features can influence gene expression. In vitro studies support a model in which chromatin functions as a barrier for the access to DNA. Therefore this organization has to be tighly regulated and dynamic to allow the protein-DNA interactions critical for nuclear functions. Importantly genome organisation provides in addition to genetic information another layer of information, so called epigenetic, which by definition means that it is stably inherited throughout cellular divisions, yet it is not encoded genetically. Thus each cell type will display a specific epigenome. We have recently constructed small human minichromosomes, which are much easier to study than the much larger normal chromosomes. The present project proposes to define the epigenetic feature across an entire human chromosome using our minichhromosomes as working models. The outcome will be a significant gain in our knowledge on the processes underlying epigenetic regulation, the organisation of specialised chromatin domain, and behaviour of the chromosomes.Read moreRead less