// publications / [1] diversity of mutational processes within and across genomes

Localized hypermutation / mutation clustering:

We classified patterns of clustered mutagenesis in tumor genomes, identifying a new pattern: nonrecurrent, diffuse hypermutation (omikli). // This mechanism occurs independently of the known focal hypermutation (kataegis), and is associated with DNA repair activity which can provide the single-stranded DNA substrate needed by APOBEC3A enzyme.
Mutation clusters in cancer genomes provide fingerprints of mutagenic mechanisms // Error-free mismatch repair lowers the mutation rate in H3K36me3-marked active genes // Error-prone repair using POLH also targets H3K36me3, contributing driver mutations // UV and alcohol increase error-prone repair, targeting mutations toward active genes.


Differential DNA repair activity across the genome:

Either an increase in the global mutation rate or a redistribution of mutations from inactive to active DNA can increase the rate at which consequential mutations are acquired. Environmental carcinogens and intrinsic mechanisms operating in tumor cells can cause cancer by this second mechanism: by specifically increasing the mutation rate in active regions of the genome.
Somatic mutation rates exhibit tissue-specificity coupled to regional changes in DNA replication timing and gene expression. A temporal deconvolution of mutational signatures in microsatellite-instable tumors of the colon, stomach and uterus demonstrates that post-replicative MMR is the cause of the megabase-scale mutation rate variability in the human genome.

Links between chromatin organization and mutagenesis:

Loss of activity of a H3K9 methyltransferase doesn't alter the global landscape of mutations in chemically induced tumors // DNA replication time and H3K36me3 histone mark, not chromatin accesibility, are determinants of mutation rates // H3K9me2/3-depleted tumors are genomically instable, and after a prolonged latency, very agressive

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