1. Erroneous identification of APOBEC3-edited chromosomal DNA in cancer genomics.
- Author
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Suspène R, Caval V, Henry M, Bouzidi MS, Wain-Hobson S, and Vartanian JP
- Subjects
- APOBEC Deaminases, CD4-Positive T-Lymphocytes drug effects, CD4-Positive T-Lymphocytes metabolism, Carcinoma, Hepatocellular etiology, Carcinoma, Hepatocellular genetics, Carcinoma, Hepatocellular metabolism, Cells, Cultured, Cytidine metabolism, Cytidine Deaminase, DNA, Neoplasm genetics, Hepatitis B, Chronic complications, Hepatitis C, Chronic complications, Humans, Interferon-alpha pharmacology, Interleukin-2 pharmacology, Liver Neoplasms etiology, Liver Neoplasms genetics, Liver Neoplasms metabolism, Nucleic Acid Denaturation, Phytohemagglutinins pharmacology, Recombination, Genetic, Temperature, beta Catenin genetics, Cytosine Deaminase metabolism, DNA, Neoplasm metabolism, Mutation, Neoplasm Proteins metabolism, Polymerase Chain Reaction methods
- Abstract
Background: The revolution in cancer genomics shows that the dominant mutations are CG->TA transitions. The sources of these mutations are probably two host cell cytidine deaminases APOBEC3A and APOBEC3B. The former in particular can access nuclear DNA and monotonously introduce phenomenal numbers of C->T mutations in the signature 5'TpC context. These can be copied as G->A transitions in the 5'GpA context., Methods: DNA hypermutated by an APOBEC3 enzyme can be recovered by a technique called 3DPCR, which stands for differential DNA denaturation PCR. This method exploits the fact that APOBEC3-edited DNA is richer in A+T compared with the reference. We explore explicitly 3DPCR error using cloned DNA., Results: Here we show that the technique has a higher error rate compared with standard PCR and can generate DNA strands containing both C->T and G->A mutations in a 5'GpCpR context. Sequences with similar traits have been recovered from human tumour DNA using 3DPCR., Conclusions: Differential DNA denaturation PCR cannot be used to identify fixed C->T transitions in cancer genomes. Presently, the overall mutation frequency is ∼10(4)-10(5) base substitutions per cancer genome, or 0.003-0.03 kb(-1). By contrast, the 3DPCR error rate is of the order of 4-20 kb(-1) owing to constant selection for AT DNA and PCR-mediated recombination. Accordingly, sequences recovered by 3DPCR harbouring mixed C->T and G->A mutations associated with the 5'GpC represent artefacts.
- Published
- 2014
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