ZYP1 is required for obligate cross-over formation and cross-over interference in Arabidopsis.

The synaptonemal complex is a tripartite proteinaceous ultrastructure that forms between homologous chromosomes during prophase I of meiosis in the majority of eukaryotes. It is characterized by the coordinated installation of transverse filament proteins between two lateral elements and is required for wild-type levels of crossing over and meiotic progression. We have generated null mutants of the duplicated Arabidopsis transverse filament genes zyp1a and zyp1b using a combination of T-DNA insertional mutants and targeted CRISPR/Cas mutagenesis. Cytological and genetic analysis of the zyp1 null mutants reveals loss of the obligate chiasma, an increase in recombination map length by 1.3- to 1.7-fold and a virtual absence of cross-over (CO) interference, determined by a significant increase in the number of double COs. At diplotene, the numbers of HEI10 foci, a marker for Class I interference-sensitive COs, are twofold greater in the zyp1 mutant compared to wild type. The increase in recombination in zyp1 does not appear to be due to the Class II interference-insensitive COs as chiasmata were reduced by ∼52% in msh5/zyp1 compared to msh5 These data suggest that ZYP1 limits the formation of closely spaced Class I COs in Arabidopsis Our data indicate that installation of ZYP1 occurs at ASY1-labeled axial bridges and that loss of the protein disrupts progressive coalignment of the chromosome axes. Copyright © 2021 the Author(s). Published by PNAS.

Citation

Martin G France, Janina Enderle, Sarah Röhrig, Holger Puchta, F Chris H Franklin, James D Higgins. ZYP1 is required for obligate cross-over formation and cross-over interference in Arabidopsis. Proceedings of the National Academy of Sciences of the United States of America. 2021 Apr 06;118(14)

PMID: 33782125

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