One of the most amazing engineering achievements in nature is how over 2 meters of genetic material (DNA) can be compacted and squeezed nearly a million times to fit into a human cell. The remarkable structure that achieves this is the chromosome. Fundamental to the survival of a multicellular organism is that the chromosome is stably maintained throughout out the life of an organism. For example, defects in maintaining chromosome stability can lead to aneuploidy (cells with an abnormal number o ....One of the most amazing engineering achievements in nature is how over 2 meters of genetic material (DNA) can be compacted and squeezed nearly a million times to fit into a human cell. The remarkable structure that achieves this is the chromosome. Fundamental to the survival of a multicellular organism is that the chromosome is stably maintained throughout out the life of an organism. For example, defects in maintaining chromosome stability can lead to aneuploidy (cells with an abnormal number of chromosomes), a feature exhibited by many forms of cancer. This packaging of genomic DNA that produces a chromosome is achieved by a complex scheme of folding. At the first level, DNA is first wrapped around a mixture of proteins (called histones) to form a complete unit known as a nucleosome. About 30 million of these building blocks are required in every human cell to compact our DNA. Higher, more complicated levels of organization exist in which a linear array of nucleosomes fold to various extents to form distinct functional and structural domains. Importantly, specialised chromosomal domains, like the telomere and centromere, are assembled that keep the ends of the chromosomes stable and enable a chromosome to copy itself every time our cells divide and grow, respectively. How a chromosome is divided into these different compartments remains a mystery. This investigation will show that a key cellular mechanism that determines how the chromosome is organised into stable domains is by changing the make-up of chromosomal domains through the replacement of histone proteins with specialised forms of histones called variants . These histone variants control the way a linear array of nucleosomes fold into complex three-dimensional structures to perform a specialised function. This fundamental research will provide important new information on how chromosomes become unstable in cancer. It will also enable new strategies, which stabilise the chromosome, to be explored.Read moreRead less
Prediction Of Clinical Radiosensitivity Caused By Ionising Radiation During Radiotherapy.
Funder
National Health and Medical Research Council
Funding Amount
$447,750.00
Summary
Around one to five percent of cancer patients suffer from significant side effects in normal tissue exposed to ionizing radiation during radiotherapy. Although radiotherapy is an effective therapy for cancer treatment, the amount of radiation is generally restricted to minimize the incidence of these severe side effects (radiosensitivity). This means that individuals who don't have radiosensitivity are not getting the dose of radiation that would be most beneficial. A major goal of radiation bio ....Around one to five percent of cancer patients suffer from significant side effects in normal tissue exposed to ionizing radiation during radiotherapy. Although radiotherapy is an effective therapy for cancer treatment, the amount of radiation is generally restricted to minimize the incidence of these severe side effects (radiosensitivity). This means that individuals who don't have radiosensitivity are not getting the dose of radiation that would be most beneficial. A major goal of radiation biology research is to develop efficient predictive measures that could identify radiosensitive individuals prior to treatment. This predictive ability would enable the individualisation of radiotherapy radiation doses, which should result in improvement of tumour control rates and a reduction in the incidence of side effects associated with radiotherapy. We aim to understand radiosensitivity at the molecular level using the powerful technology of microarrays. Using microarray technology, thousands of genes can be tested for expression activity simultaneously. We have a unique tissue bank established from many radiosensitive and non-sensitive control radiotherapy patients. The use of microarray technology on samples from this unique tissue bank may enable the gene expression pattern of individuals that display radiosensitivity to be distinguished from the rest of the population. In conjunction, two additional tests will be used to determine who is susceptible to radiosensitive reactions which include assessment of a DNA repair pathway and assessment of the length of the telomeres (Caps on the ends of the chromosomes), both of which have been shown to be involved with radiosensitivy. This experimentation will hopefully lead to the development of a predictive assay for use in the clinic for cancer patients prior to receiving radiotherapy.Read moreRead less