Biochemistry, Genetics and Molecular Biology · Molecular Biology
Different forms of DNA damage changed the shape and movement of surrounding DNA in laboratory tests. The findings suggest that these physical changes could provide an early signal that helps repair proteins locate damage, before they directly engage with it.
Researchers tracked homologous mouse chromosomes as they paired during meiosis, the specialized cell division that produces reproductive cells. The chromosomes moved from widely separated positions to close alignment in three stages, with DNA breaks and recombination helping drive the transitions.
Researchers have determined how two DNA repair proteins, polymerase lambda and PNKP, work together in a complex that brings broken DNA ends into close contact. The findings suggest that this large repair complex can process several types of damaged DNA ends so they can be joined.
Researchers found that sister copies of human chromosomes have a previously unrecognized difference in their large-scale three-dimensional arrangement. The shift is linked to the protein complexes that hold the copies together and could affect how cells find matching DNA during repair.
