This thesis aims to gain a better understanding of NER, to elucidate new molecular mechanisms and proteins that orchestrate how DNA repair is carried out on genomic DNA that is tightly packed in... Show moreThis thesis aims to gain a better understanding of NER, to elucidate new molecular mechanisms and proteins that orchestrate how DNA repair is carried out on genomic DNA that is tightly packed in chromatin inside the living cell. It is important to obtain a better clinical picture of how inherited defects in DNA repair genes shapes phenotypes in patients with DNA repair-deficiency disorders. Show less
To protect the genome, cells have evolved a diverse set of pathways designed to sense, signal, and repair multiple types of DNA damage. To assess the degree of coordination and crosstalk among... Show moreTo protect the genome, cells have evolved a diverse set of pathways designed to sense, signal, and repair multiple types of DNA damage. To assess the degree of coordination and crosstalk among these pathways, we systematically mapped changes in the cell's genetic network across a panel of different DNA-damaging agents, resulting in ~1,800,000 differential measurements. Each agent was associated with a distinct interaction pattern, which, unlike single-mutant phenotypes or gene expression data, has high statistical power to pinpoint the specific repair mechanisms at work. The agent-specific networks revealed roles for the histone acetyltranferase Rtt109 in the mutagenic bypass of DNA lesions and the neddylation machinery in cell-cycle regulation and genome stability, while the network induced by multiple agents implicates Irc21, an uncharacterized protein, in checkpoint control and DNA repair. Our multiconditional genetic interaction map provides a unique resource that identifies agent-specific and general DNA damage response pathways. Show less
DNA damage, mutations and genomic instability are established driving forces of cancer and other age-related diseases. Mutations in tumor suppressor genes and oncogenes are very frequently found in... Show moreDNA damage, mutations and genomic instability are established driving forces of cancer and other age-related diseases. Mutations in tumor suppressor genes and oncogenes are very frequently found in tumors and genomic instability is the most common enabling characteristic of cancer. Aging is also believed to be enabled, amongst others, by genomic instability. DNA repair pathways, like the nucleotide excision repair (NER) pathway and cell cycle control (e.g. p53-dependent) processes are therefore vital to organisms, since these processes counteract or prevent genomic instability, and are thought to underlie, when affected, aging and age-related diseases like cancer. To unravel the functions, mechanisms and pathways involved in the onset of aging and age-related diseases we have investigated several mouse models deficient in either DNA repair (NER) capacity (Chapter 3, 4), cell cycle control (p53) (Chapter 6) or both (Chapter 5), and compared this to a wild type situation (Chapter 2). The use of mouse models enabled us to investigate cancer and aging in a controlled environment, minimizing possible confounding factors. Additionally, the mouse models can be useful as an alternative tool to identify genotoxic and non-genotoxic carcinogens that can be harmful to the society and the environment (Chapter 5). Show less
