Chromosome replication and genome stability.
DNA damage is largely inevitable and a major cause of genomic instability, which is a hallmark of cancer as well as a feature of neurological disorders, premature aging, inflammatory signalling and developmental abnormalities. To maintain genome integrity, cells have complex DNA damage detection and repair pathways, but, despite their efficiency, some DNA lesions escape repair and need to be tolerated. This is particularly important during chromosome replication, as unrepaired DNA lesions can block replication forks, impeding faithful genome duplication and leading to genomic instability. Cells cope with these problems thanks to evolutionarily conserved DNA damage tolerance (DDT) mechanisms that allow overcoming unrepaired DNA lesions that halt replication forks. These mechanisms facilitate the completion of chromosome replication when the DNA is damaged, thus being crucial for genome integrity maintenance in every cell cycle. DDT is mainly carried out by homologous recombination-mediated bypass by template switching, largely error-free, or translesion DNA synthesis, frequently error-prone. These processes are interconnected, driven by post-translational modifications of PCNA, and mediated, respectively, by budding yeast Rad5 (human HLTF), an E3 ubiquitin ligase with ATPase/helicase activity that plays a central role in DDT, or specialized (TLS) DNA polymerases than can replicate across DNA lesions. Despite the progress made in recent years, little is known about how the components of DDT are regulated, how cells choose between the types of DNA damage bypass and how different proteins modulate DDT in coordination with other cellular processes. The aim of the project and our group is to address these questions to contribute to a better understanding of how eukaryotic cells cope with DNA damage-induced replicative stress in order to maintain genome stability.
The work will be aimed at the completion of a master’s degree final project, with the possibility of later extending it to a doctoral thesis. The project will focus on the study of the regulation and function of DNA damage tolerance (DDT) mechanisms and their relevance for the maintenance of genome integrity. This a topic of general interest with impact in basic research and biomedicine. It has a multidisciplinary character and will facilitate the candidate a good training. It will be carried out in the Chromosome and Genome Stability Lab of the Centro de Biología Molecular Severo Ochoa (CBM). The research plan will include the study of: (1) subcellular relocalization of DDT proteins under stress conditions; (2) post-translational modifications of DDT proteins that are relevant for their function or regulation; (3) modulation of DDT by different pathways; (4) crosstalk between DDT branches and of these with other cellular processes involved in cellular homeostasis. The methodology will combine molecular biology, genetics, cell biology and biochemistry techniques. Since the processes to be studied are evolutionary conserved, the genetically tractable yeast Saccharomyces cerevisiae will be used as a working eukaryotic model. S. cerevisiae is a powerful tool for in-depth study of fundamental molecular mechanisms and has been extremely useful to establish the molecular bases of a number of pathologies.
José Antonio Tercero Orduña.
Correo electrónico: jatercero@cbm.csic.es.
Centro de Biología Molecular Severo Ochoa (CBM).
Número de plazas ofertadas: 1.
Facultad de Medicina. Universidad Autónoma de Madrid. Calle del Arzobispo Morcillo 4. 28029 Madrid. Tel.: +34 914 975 486. Correo electrónico: informacion.medicina@uam.es
