Characterisation of ASYNAPTIC 4: a novel meiotic chromosome axis associated protein in Arabidopsis thaliana


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Darbyshire, Alice R. ORCID: (2019). Characterisation of ASYNAPTIC 4: a novel meiotic chromosome axis associated protein in Arabidopsis thaliana. University of Birmingham. Ph.D.

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Formation of genetic crossovers (COs) during prophase I of meiosis is essential for faithful segregation of chromosomes at anaphase I. As in many organisms, in Arabidopsis thaliana, CO number and distribution is non-random, and thus understanding the factors that influence CO localization is of great interest. One such factor is the chromosome axis: a proteinaceous meshwork that organizes the chromatin into a linear array of loops. Previous work has identified ASY1 and ASY3 (homologues of yeast Hop1 and Red1 respectively) as key constituents of the axis in A. thaliana.

In this study, we commence a functional analysis of novel chromosome axis associated protein ASY4, identified via immuno-affinity proteomics with ASY1. Using a range of cytological and molecular techniques including structured-illumination microscopy and CRISPR-Cas9, we confirm that ASY4 is required for normal fertility, CO number and maturation, axis structure, and synapsis in A. thaliana. Using both an antibody raised against ASY4 and ASY4 tagged with yellow fluorescent protein, we show that ASY4 is associated with the chromosome axis during prophase I of meiosis. We confirm that ASY4 is a direct interacting partner of core axis protein ASY3, and that this is potentially facilitated through the second coiled-coil domain of ASY4. Combined, this data shows ASY4 to be an essential component of the meiotic chromosome axis in A. thaliana, and highlights the importance of the axis structure in crossover formation.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
Licence: All rights reserved
College/Faculty: Colleges (2008 onwards) > College of Life & Environmental Sciences
School or Department: School of Biosciences
Funders: Biotechnology and Biological Sciences Research Council
Subjects: Q Science > Q Science (General)
Q Science > QH Natural history > QH301 Biology
Q Science > QH Natural history > QH426 Genetics
Q Science > QK Botany


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