Diffusion-mediated HEI10 coarsening can explain meiotic crossover positioning in Arabidopsis.


Type
Article
Change log
Authors
Hartley, Matthew 
Henderson, Ian R 
Bomblies, Kirsten 
Abstract

In most organisms, the number and distribution of crossovers that occur during meiosis are tightly controlled. All chromosomes must receive at least one 'obligatory crossover' and crossovers are prevented from occurring near one another by 'crossover interference'. However, the mechanistic basis of this phenomenon of crossover interference has remained mostly mysterious. Using quantitative super-resolution cytogenetics and mathematical modelling, we investigate crossover positioning in the Arabidopsis thaliana wild-type, an over-expressor of the conserved E3 ligase HEI10, and a hei10 heterozygous line. We show that crossover positions can be explained by a predictive, diffusion-mediated coarsening model, in which large, approximately evenly-spaced HEI10 foci grow at the expense of smaller, closely-spaced clusters. We propose this coarsening process explains many aspects of Arabidopsis crossover positioning, including crossover interference. Consistent with this model, we also demonstrate that crossover positioning can be predictably modified in vivo simply by altering HEI10 dosage, with higher and lower dosage leading to weaker and stronger crossover interference, respectively. As HEI10 is a conserved member of the RING finger protein family that functions in the interference-sensitive pathway for crossover formation, we anticipate that similar mechanisms may regulate crossover positioning in diverse eukaryotes.

Description
Keywords
Arabidopsis, Arabidopsis Proteins, Chromosomal Proteins, Non-Histone, Chromosomes, Plant, Computer Simulation, Crossing Over, Genetic, Gene Dosage, Meiosis, Pachytene Stage, Synaptonemal Complex
Journal Title
Nat Commun
Conference Name
Journal ISSN
2041-1723
2041-1723
Volume Title
12
Publisher
Springer Science and Business Media LLC
Sponsorship
Leverhulme Trust (RPG-2019-259)