Role of the post-translational modification citrullination in DNA damage tolerance responses

• Grant number: 24/14346-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: December 01, 2024
• End date: September 30, 2025
• Field of knowledge: Biological Sciences - Genetics - Mutagenesis
• Principal Investigator: Carlos Frederico Martins Menck
• Grantee: Fernanda Marques Câmara Sodré
• Supervisor: Annabel Quinet de Andrade
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Institut De Biologie François Jacob, France
• Associated to the scholarship: 21/09294-3 - Impact of post-translational protein modifications on human cells with genome damage and cell transformation, BP.PD

Abstract

DNA is constantly exposed to endogenous and exogenous agents that cause its damage. Such damage can lead to transient slowing or stalling of replication forks, a process known as "replication stress". To solve replication stress and, therefore, keep genome stability and cell viability, cells present defense mechanisms of DNA damage tolerance, including translesion synthesis (TLS), template switching and repriming. The choice between these pathways will depend on the nature of the replication challenge. UV-induced lesions, that cause DNA double helix distortions, are tolerated mainly by TLS, since specific TLS DNA polymerases, like Pol eta, can bypass this type of lesion. Our results have shown that, in Pol eta-deficient cells, if the post-translational modification (PTM) citrullination is chemically inhibited, cell viability is reduced after UVA or UVB irradiation. These results suggest a role of citrullination in recovery of stalled replication forks in the absence of Pol eta. In order to investigate further, we aim to collaborate with Dr. Annabel Quinet's lab (CEA/INSERM, France), a research group with a great expertise in DNA replication stress and DNA damage tolerance. We plan to explore how citrullination inhibition, chemically or by knocking down enzymes responsible for citrullination, in TLS-defective cells impacts replication fork dynamics. For this, we will assess replication fork progression by DNA fiber assay, post-replicative gap formation by S1-modified DNA fiber assay and profile of proteins recruited to replicating forks by iPOND. This collaboration would be of huge value to answer questions on how citrullination is involved in replication stress and DNA damage response. Exploring this novel hypothesis will probably impact the DNA damage field, since there is a gap of knowledge about the involvement of PTMs and DNA damage response.