title: The Axial Element Protein DESYNAPTIC2 Mediates Meiotic Double-Strand Break Formation and Synaptonemal Complex Assembly in Maize.
abstract: During meiosis, homologous chromosomes pair and recombine via repair of programmed DNA double-strand breaks (DSBs). DSBs are formed in the context of chromatin loops, which are anchored to the proteinaceous axial element (AE). The AE later serves as a framework to assemble the synaptonemal complex (SC) that provides a transient but tight connection between homologous chromosomes. Here, we showed that DESYNAPTIC2 (DSY2), a coiled-coil protein, mediates DSB formation and is directly involved in SC assembly in maize (Zea mays). The dsy2 mutant exhibits homologous pairing defects, leading to sterility. Analyses revealed that DSB formation and the number of RADIATION SENSITIVE51 (RAD51) foci are largely reduced, and synapsis is completely abolished in dsy2 meiocytes. Super-resolution structured illumination microscopy showed that DSY2 is located on the AE and forms a distinct alternating pattern with the HORMA-domain protein ASYNAPTIC1 (ASY1). In the dsy2 mutant, localization of ASY1 is affected, and loading of the central element ZIPPER1 (ZYP1) is disrupted. Yeast two-hybrid and bimolecular fluorescence complementation experiments further demonstrated that ZYP1 interacts with DSY2 but does not interact with ASY1. Therefore, DSY2, an AE protein, not only mediates DSB formation but also bridges the AE and central element of SC during meiosis.
authors: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan National Chung-Hsing University, Taichung 40227, Taiwan Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung 40227, Taiwan.
authors: Ding Hua
authors: http://orcid.org/0000-0001-5475-4287
authors: DH
authors: Lee
authors: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors: Yu-Hsin
authors: YH
authors: Kao
authors: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors: Jia-Chi
authors: JC
authors: Ku
authors: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors: Chien-Yu
authors: CY
authors: Lin
authors: Crop Genetics Research, Pioneer Hi-Bred-A DuPont Business, Johnston, Iowa 50131.
authors: Robert
authors: R
authors: Meeley
authors: Potzu Branch Station, Tainan District Agricultural Research and Extension Station, Chiayi 61359, Taiwan.
authors: Ya-Shiun
authors: http://orcid.org/0000-0002-0166-359X
authors: YS
authors: Jan
authors: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan National Chung-Hsing University, Taichung 40227, Taiwan Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan rwang@gate.sinica.edu.tw.
authors: Chung-Ju Rachel
authors: http://orcid.org/0000-0002-1046-3012
authors: CJ
authors: Wang
mesh_terms: D053903:DNA Breaks, Double-Stranded; D018506:Gene Expression Regulation, Plant; D059765:Homologous Recombination; D008540:Meiosis; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D013573:Synaptonemal Complex / Q000235:genetics / Q000378:metabolism*; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins