Optimized high‐fidelity 3DPCR to assess potential mitochondrial targeting by activation‐induced cytidine deaminase

Abstract

Here, we develop a high‐fidelity differential DNA denaturation PCR approach and investigate whether activation‐induced cytidine deaminase (AID) can target mitochondrial DNA (mtDNA) in vitro. We demonstrate AID targeting of mtDNA is a rare event. Despite a fraction of AID binding the mitochondrial outer membrane, it is unable to access the mitochondrial matrix or the mtDNA. Thus, the mitochondrial genome is protected from AID‐mediated mutagenesis by physical segregation.

Mutagenic Activity of AID/APOBEC Deaminases in Antiviral Defense and Carcinogenesis

“…In nasopharyngeal cancer induced by the Epstein-Barr virus, induction of APOBEC3B and APOBEC3F, which correlated with the frequency of G→A transitions in mitochondrial DNA, was found [29]. However, the analysis of mitochondrial DNA from B-cell lymphoma lines with high levels of AID expression reveals almost no mutations caused by cytidine deaminases [30]. It is assumed that mitochondrial DNA is deaminated by cytidine deaminases exclusively in the cytoplasm [31].…”