The role of protein arginine methylation in the DNA damage response

McFadzean, Nicole ORCID: 0009-0003-1451-6737 (2024). The role of protein arginine methylation in the DNA damage response. University of Birmingham. Ph.D.

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Abstract

Arginine methylation is a prevalent post-translational modification (PTM) that plays critical roles in multiple cellular processes, including transcription, splicing, and the DNA damage response (DDR). Histone arginine methylation at H3R2 and H4R3 has been linked to transcriptional regulation and more recently to the DDR. Therefore, we investigated the dynamics of protein arginine methyltransferases (PRMTs) and of histone arginine methylation at sites of DNA double-strand breaks (DSBs) and stalled replication forks (RFs) using U2OS cell- line reporter systems. Our data indicates that PRMT1, 4, 5 and 6 are not recruited to these sites, and H3R2me2s, H4R3me2a and H4R3me2s is not dynamically regulated post-DNA damage. However, our analysis of available data investigating histone mutations within cancer has identified H3R2G and H4R3C as common histone mutations. Importantly, the integrity of H4R3 and H3R2 in genomic stability and DNA repair were highlighted, as H3R2G and H4R3C mutations increased DNA damage and impaired DNA repair without altering global histone methylation patterns. Notably, H4R3C mutation, the most common documented Histone H4 mutation led to persistent DNA damage, genomic instability, and increased transcription, potentially through affecting R-loop dynamics.

Finally, to overcome the biases introduced by the use of pan-methylarginine antibodies for novel substrate identification after genotoxic stress, we developed a novel system for the enrichment of symmetrically dimethylated arginine (SDMA)-bearing proteins using the Tudor domain of the survival (of) motor neuron (SMN) protein. Through this approach we identified several potential
novel PRMT5 substrates and novel methylation events. Therefore, our novel system shows promise as an alternative strategy in identifying new PRMT5 substrates, which, together with the advances in mass spectrometry and sequencing technology can help elucidate the roles of PRMTs and arginine methylation.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):