Genes Dev.-2015-Matsuzaki-2532-46.pdf (909.52 kB)

FANCJ suppresses microsatellite instability and lymphomagenesis independent of the Fanconi anemia pathway

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journal contribution
posted on 28.08.2020 by Kenichiro Matsuzaki, Valerie Borel, Carrie A Adelman, Detlev Schindler, Simon J Boulton
Microsatellites are short tandem repeat sequences that are highly prone to expansion/contraction due to their propensity to form non-B-form DNA structures, which hinder DNA polymerases and provoke template slippage. Although error correction by mismatch repair plays a key role in preventing microsatellite instability (MSI), which is a hallmark of Lynch syndrome, activities must also exist that unwind secondary structures to facilitate replication fidelity. Here, we report that Fancj helicase-deficient mice, while phenotypically resembling Fanconi anemia (FA), are also hypersensitive to replication inhibitors and predisposed to lymphoma. Whereas metabolism of G4-DNA structures is largely unaffected in Fancj(-/-) mice, high levels of spontaneous MSI occur, which is exacerbated by replication inhibition. In contrast, MSI is not observed in Fancd2(-/-) mice but is prevalent in human FA-J patients. Together, these data implicate FANCJ as a key factor required to counteract MSI, which is functionally distinct from its role in the FA pathway.