Intragenic Mutation Screen
| Overview |
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Small intragenic mutations are commonly found in both recessive oncogenes and dominantly acting
oncogenes. Therefore the search for and detection of this type of mutation will lead to
identification of both classes of oncogene, including those for which no positional mapping
information is available. The presence of small intragenic mutations (in particular those
that are predicted to encode truncated versions of the protein) is regarded as the strongest
structural evidence that a gene is a recessive oncogene. It also is often the only class of
structural change found in many dominantly acting oncogenes in human cancers.
This project is systematically screening coding exons and flanking splice junctions of all
genes in the human genome for somatically acquired small intragenic mutations in human cancer.
For this study we are using DNA from primary tumours and normal genomic DNA from the same individuals
in addition to cancer cell lines.
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| Strategy |
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We are designing PCR primers to flank the coding exons and splice junctions of genes in the
human genome. The first sets of genes include protein kinases and other genes that are potential
therapeutic targets. The genes are amplified by the PCR and the products sequenced. The sequences are
compared with a control samples to identify novel variants in the tumour samples.
When these are found the tumour is resequenced along with it's matched normal DNA to
ascertain if the variant is a somatic mutation. The significance of mutated genes is
evaluated by screening a larger series of cancers.
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Normal BRAF DNA sequence
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Mutant BRAF DNA sequence
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The above sequences show a normal BRAF sequence and an ovarian tumour with a T to A mutation at nucleotide position 1799 leading to a V to E amino acid substitution at residue 600.
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| Results |
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The results from this work are collated and stored in COSMIC. In addition, COSMIC contains somatic mutation data that has been published in the scientific literature.
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