Project description:Interventions: To measure the registration error in the target point indicated by laparoscopic forceps with infra-red tracking system.
Primary outcome(s): target registration error(TRE)
Study Design: Single arm Non-randomized
Project description:DNA replication is sensitive to damage in the template. To bypass lesions and complete replication, cells activate recombination-mediated (error-free) and translesion synthesis-mediated (error-prone) DNA damage tolerance pathways. Crucial for error-free DNA damage tolerance is template switching, which depends on the formation and resolution of damage-bypass intermediates consisting of sister chromatid junctions. Here we show that a chromatin architectural pathway involving the high mobility group box protein Hmo1 channels replication-associated lesions into the error-free DNA damage tolerance pathway mediated by Rad5 and PCNA polyubiquitylation, while preventing mutagenic bypass and toxic recombination. In the process of template switching, Hmo1 also promotes sister chromatid junction formation predominantly during replication. Its C-terminal tail, implicated in chromatin bending, facilitates the formation of catenations/hemicatenations and mediates the roles of Hmo1 in DNA damage tolerance pathway choice and sister chromatid junction formation. Together, the results suggest that replication-associated topological changes involving the molecular DNA bender, Hmo1, set the stage for dedicated repair reactions that limit errors during replication and impact on genome stability.
Project description:The DNA damage inducible SOS response in bacteria serves to increase survival of the species. The SOS response first initiates error-free repair which is followed by error-prone repair. Here, we have employed a multi-omics approach to elucidate the temporal coordination of the SOS response using transcriptomics, signalomics, and metabolomics. Escherichia coli was grown in batch cultivation in bioreactors to ensure highly controlled conditions. Ciprofloxacin was used to induce the SOS response at a concentration that avoided extensive cell death. Our results show that expression of genes involved in error-free and error-prone repair were both induced shortly after DNA damage, thus, challenging the established perception that the expression of error-prone repair genes is delayed. By combining transcriptomics with signalomics, we found that temporal segregation of error-free and error-prone repair is primarily regulated after transcription. Furthermore, the heterology index was correlated to the maximum increase in gene expression and not to the time of induction of SOS genes. Finally, quantification of metabolites revealed an increase in pyrimidine pools as a late feature of the SOS response. Our results elucidate how the SOS response is coordinated, showing a rapid transcriptional response and temporal regulation of mutagenesis on the protein and metabolite levels.