In G2 phase cells, DNA double-strand break repair switches from DNA non-homologous end-joining to homologous recombination. This switch demands the promotion of resection. We examine the changes in 53BP1 and RAP80 ionizing radiation induced foci (IRIF) in G2 phase, as these are factors that restrict resection. We observed a 2-fold increase in the volume of 53BP1 foci by 8 h, which is not seen i...

During meiosis, recombination is directed to occur between homologous chromosomes to create connections necessary for proper segregation at meiosis I. Partner choice is determined at the time of strand invasion and is mediated by two recombinases: Rad51 and the meiosis-specific Dmc1. In budding yeast, interhomolog bias is created in part by the activity of a meiosis-specific kinase, Mek1, which...

Dose- and time-response curves were combined to assess the potential of the comet assay in radiation biodosimetry. The neutral comet assay was used to detect DNA double-strand breaks in lymphocytes caused by γ-ray irradiation. A clear dose-response relationship with DNA double-strand breaks using the comet assay was found at different times after irradiation (p < 0.001). A time-response relatio...

The contributions of the Sgs1, Mph1, and Srs2 DNA helicases during mitotic double-strand break (DSB) repair in yeast were investigated using a gap-repair assay. A diverged chromosomal substrate was used as a repair template for the gapped plasmid, allowing mismatch-containing heteroduplex DNA (hDNA) formed during recombination to be monitored. Overall DSB repair efficiencies and the proportions...

Homologous recombination (HR) is essential for repair of meiotic DNA double-strand breaks (DSBs). Although the mechanisms of RAD-51-DNA filament assembly and strand exchange are well characterized, the subsequent steps of HR are less well defined. Here, we describe a synthetic lethal interaction between the C. elegans helicase helq-1 and RAD-51 paralog rfs-1, which results in a block to meiotic...

Meets DNA Transcription and Recombination: When RNA Andrés Aguilera and Hélène Gaillard Mechanism and Regulation End Resection at Double-Strand Breaks: Lorraine S. Symington Resection in Homologous Recombination Structural Studies of DNA End Detection and Christian Linke-Winnebeck, et al. Christian Bernd Schiller, Florian Ulrich Seifert, The Dissolution of Double Holliday Junctions Anna H. Biza...

Mitotic double-strand break (DSB)-induced gene conversion at MAT in Saccharomyces cerevisiae was analyzed molecularly in mutant strains thermosensitive for essential replication factors. The processivity cofactors PCNA and RFC are essential even to synthesize as little as 30 nucleotides following strand invasion. Both PCNA-associated DNA polymerases delta and epsilon are important for gene conv...

In yeast, the nonhomologous end joining pathway (NHEJ) mobilizes the DNA polymerase Pol4 to repair DNA double-strand breaks when gap filling is required prior to ligation. Using telomere-telomere fusions caused by loss of the telomeric protein Rap1 and double-strand break repair on transformed DNA as assays for NHEJ between fully uncohesive ends, we show that Pol4 is able to extend a 3'-end who...

The transformation of biochemical information into a physical or chemical signal is the basic idea behind a biosensor. The efficient detection of charged biomolecules by biosensor with appropriate device has caught tremendous research interest in the present decade. The present work is related to the simulation study of the performance of a functionalized surface of a biologically sensitive fie...

Background: Immunotoxins are comprised of both the cell targeting and the cell killing moieties. We previously established a new immunotoxin, i.e. Shiga toxin granulocyte macrophage-colony stimulating factor (StxA1-GM-CSF), comprises of catalytic domain of Stx, as a killing moiety and GM-CSF, as a cell targeting moiety. In this study, the ability of the immunotoxin to induce apoptosis and dou...