Abstract
Cohesin, a multisubunit protein complex, is required for holding sister chromatids together during mitosis and meiosis. The recruitment of cohesin by the sister chromatid cohesion 2/4 (SCC2/4) complex has been extensively studied in Saccharomyces cerevisiae mitosis, but its role in mitosis and meiosis remains poorly understood in multicellular organisms, because complete loss-of-function of either gene causes embryonic lethality. Here, we identified a weak allele of Atscc2 (Atscc2-5) that has only minor defects in vegetative development but exhibits a significant reduction in fertility. Cytological analyses of Atscc2-5 reveal multiple meiotic phenotypes including defects in chromosomal axis formation, meiosis-specific cohesin loading, homolog pairing and synapsis, and AtSPO11-1-dependent double strand break repair. Surprisingly, even though AtSCC2 interacts with AtSCC4 in vitro and in vivo, meiosis-specific knockdown of AtSCC4 expression does not cause any meiotic defect, suggesting that the SCC2-SCC4 complex has divergent roles in mitosis and meiosis. SCC2 homologs from land plants have a unique plant homeodomain (PHD) motif not found in other species. We show that the AtSCC2 PHD domain can bind to the N terminus of histones and is required for meiosis but not mitosis. Taken together, our results provide evidence that unlike SCC2 in other organisms, SCC2 requires a functional PHD domain during meiosis in land plants.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Arabidopsis / genetics*
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Arabidopsis / growth & development
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Arabidopsis / metabolism
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Arabidopsis Proteins / chemistry
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Arabidopsis Proteins / genetics*
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Arabidopsis Proteins / metabolism
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Carrier Proteins / genetics*
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Carrier Proteins / metabolism
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Cell Cycle Proteins / chemistry
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Chromosomal Proteins, Non-Histone / chemistry
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Chromosomal Proteins, Non-Histone / genetics
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Chromosomal Proteins, Non-Histone / metabolism*
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Cohesins
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Gene Knockdown Techniques
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Genome, Plant / genetics
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Loss of Function Mutation
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Meiosis / genetics*
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Mitosis / genetics
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Morphogenesis / genetics
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Mutagenesis
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PHD Zinc Fingers / genetics*
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Plants, Genetically Modified
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Pollination / genetics
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Whole Genome Sequencing
Substances
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AT5G15540 protein, Arabidopsis
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Arabidopsis Proteins
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Carrier Proteins
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Cell Cycle Proteins
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Chromosomal Proteins, Non-Histone
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SCC4 protein, Arabidopsis
Grants and funding
This work was supported by the National Science Foundation of China grant (31925005 and 31870293); the US National Science Foundation grant (IOS-1844264) and funds from the State Key Laboratory of Genetic Engineering, Fudan University; University of North Carolina at Chapel Hill. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.