Abstract
Cohesin is a multi-subunit protein that plays a pivotal role in holding sister chromatids together during cell division. Sister chromatid cohesion 3 (SCC3), constituents of cohesin complex, is highly conserved from yeast to mammals. Since the deletion of individual cohesin subunit always causes lethality, it is difficult to dissect its biological function in both mitosis and meiosis. Here, we obtained scc3 weak mutants using CRISPR-Cas9 system to explore its function during rice mitosis and meiosis. The scc3 weak mutants displayed obvious vegetative defects and complete sterility, underscoring the essential roles of SCC3 in both mitosis and meiosis. SCC3 is localized on chromatin from interphase to prometaphase in mitosis. However, in meiosis, SCC3 acts as an axial element during early prophase I and subsequently situates onto centromeric regions following the disassembly of the synaptonemal complex. The loading of SCC3 onto meiotic chromosomes depends on REC8. scc3 shows severe defects in homologous pairing and synapsis. Consequently, SCC3 functions as an axial element that is essential for maintaining homologous chromosome pairing and synapsis during meiosis.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
The specific changes implemented in the revised manuscript are outlined below: -Revised the title of the manuscript. -Revised the description of early mitotic and meiotic chromosome structure in the scc3 mutant (Lines 167-274). -Added the BiFC results illustrating the interaction between SCC3 and other cohesin proteins in Figure S10. -Enhanced the detail in the description of figure legends, particularly for Figures 2 and 4. -Refined and rephrased the language of the manuscript.
