Transition of DNA double-strand breaks to genetic crossovers

Since more than 10 000 years humans are growing crop plants, selecting for local adaption, high yields and further traits to deliver food security. These efforts are still ongoing, now framed by well controlled plant breeding programs. Though, it has long been recognized that not all beneficial traits of a certain crop species, present in various sub-species, can be combined in the same individual plant. Only recently, the molecular base for this impediment starts to emerge, relating to specific processes during meiosis. Meiosis is a specialised cell division that ensures the reduction of the genome prior to the formation of generative cells. During meiosis, novel combinations between parts of paternal and maternal chromosomes are generated through the process of homologous recombination (HR). A pre-requisite for HR are DNA double strand breaks (DSBs). Previously, a lot of effort has been dedicated towards understanding the determinants and the mechanisms of meiotic DSB formation and members of the given MEIOREC consortium contributed significantly. While meiotic DSBs are essential for subsequent exchange of parental genetic information, less than 10% of meiotic DSBs actually constitute such an exchange point. It is not understood, how the fate of a DSB at a certain genomic locus is determined and hence what limits the maturation of a meiotic DSB into a genetic exchange point, a cross-over (CO). The MEIOREC researchers have harnessed a research program to remedy this shortcoming of understanding and will experimentally address various aspect of the DSB-to-CO transition. In the frame of the proposed project, the group of Karl Mechtler based at the Research Institute of Molecular Pathology in Vienna will analyse certain characteristics of protein complexes by mass spectrometry (MS), which play crucial roles during the meiotic cell cycle in relation to recombination. MS techniques will be used to map sites of protein-protein interactions within protein complexes, which will be provided by the consortium partners. New reagents and MS methods will be tested and evaluated to improve established protocols. In addition to MS, the group of Karl Mechtler will provide the expertise and the technology (peptide array) for very detailed studies of protein interacting domains in vitro. Additionally, MS will be applied to study dynamic changes in the modifications of meiotic proteins involved in chromosome axis formation during different phases of the meiotic cell cycle. Here, the kind of modification will be identified, localized on the protein and the changes in their occurrence will be relatively quantified. These analyses will allow to pinpoint modifications, that potentially have an influence on the programmed remodeling of the chromosome axis during meiosis.

No additional funding sources recorded.