Chromosome axis organization in relation to the coordination of meiotic recombination

Martínez García, Marina (2017). Chromosome axis organization in relation to the coordination of meiotic recombination. University of Birmingham. Ph.D.

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Abstract

DNA topology is dependent on axis proteins during eukaryotic cellular processes. Chromosome axis organization is complex during meiosis, when DNA repair needs to be coordinated with homology searching and synapsis. Although roles for the axis component Topoisomerase II (TOPII) and the post-translational modification (PTM) of ASY1 homologues during meiosis have previously been reported, few studies have been performed in plants. The aim of this thesis is to investigate the effects of these proteins on meiotic DNA topology and axis morphology, and their implications for homologous recombination (HR) in Arabidopsis thaliana. Using a combination of cytogenetic and molecular techniques, we show the role of PTM of ASY1 differs from that of its budding yeast orthologue. Phosphorylation of a plant specific set of residues in ASY1 affected chiasmata distribution. Analysis of the first TOPII mutants described in plants also revealed a link with HR. Chromosome replication, condensation and segregation phenotypes were consistent with previous studies of TOPII in other organisms. For the first time, we report that TOPII and chromosome movement collaborate in interlock resolution during meiosis, confirming predictions from decades ago. Overall, these investigations have revealed new roles for the axis in plant meiosis, which could have potential for crop breeding.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):