Meiotic recombination generates novel allelic combinations that may be selected in the progeny. It is therefore essential for evolution, whilst also necessary for accurate chromosome segregation and gamete formation in sexually reproducing organisms. Meiotic recombination is initiated by formation of double stranded breaks and ends in repair either as crossovers (reciprocal exchange of DNA) or non-crossovers (non-reciprocal exchange). This process is highly dynamic and characterised by chromosome morphogenesis and formation of the synaptonemal complex.
The SC is a meiosis specific tripartite protein structure that is required for normal levels of meiotic crossing over in the majority of eukaryotic organisms. The SC consists of two axes that are organized by a cohesin protein scaffold onto homologous chromosomes, joined by a central element. In plants, mammals and yeast, the majority, if not all of the axial components have been identified, showing a degree of structural, but not primary amino acid sequence similarity. The SC central element transverse filament proteins have also been identified in these organisms, however, in mammals and yeast, additional small helical proteins have been identified that are required to maintain fidelity of the SC structure. This would imply that similar proteins exist in plants, but these have not yet been identified due to lack of sequence homology, possible redundancy, and perhaps no clear phenotypes in mutant screens. Therefore, the aim of this project is to identify candidates for SC central element proteins in Arabidopsis and characterise their function. Candidates will be identified using bioinformatic approaches to screen for small helical proteins that are highly expressed in floral tissues. Candidate genes will be verified using T-DNA mutants (if available) and/or CRISPR/Cas, followed by generating polyclonal antibodies to perform immunolocalisation analyses. Immunolocalisation will be conducted using the Zeiss Airyscan confocal super-resolution microscope at the University of Leicester (awarded in BBSRC Alert18) and structural analysis will be performed in vitro using recombinant proteins generated in E. coli Rosetta strain expression cells in collaboration with Dr Owen Davies (University of Newcastle). If potential candidates do not come to fruition then the project will refocus on establishing the role of the known SC components, especially ZYP1, as well as the opportunity to work on budding yeast SC components.
This studentship provides the opportunity to make a substantial contribution to science as well as using cutting edge techniques.