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.
Highlights
The faithful transmission of chromosomes to daughter cells is an essential feature of the cell cycle in most eukaryotes
In Zea mays, SCC4/Dek15 interacts with several chromatin remodeling proteins [35]. These results suggest that recruitment of sister chromatid cohesion 2/4 (SCC2/4) onto chromatin likely depends on SCC4-interacting factors such as Ctf19 and the MCM2-7 complex, while SCC2 is important for loading cohesin
Our analyses demonstrate that AtSCC2 acts in the same pathway as AtSYN1 and AtWAPL1/2, and participates in AtSPO11-1-depedent double strand break (DSB) repair
Summary
The faithful transmission of chromosomes to daughter cells is an essential feature of the cell cycle in most eukaryotes. Scc is able to interact with the kleisin subunit [6] These four subunits form a ring-shaped structure [7]. AtSYN1, the orthologue of yeast Rec, is a meiosis-specific cohesin subunit and is essential for chromosome condensation, sister chromatid cohesion, double strand break (DSB) repair and mono-orientation of meiotic chromosome [9, 16, 17]. Other accessory proteins such as AtSWITCH1 (AtSWI1) and AtWAPL1/AtWAPL2, help mediate cohesin association or disassociation with chromatin [18,19,20,21]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
