ABSTRACT
Factors regulating dynamics of chromatin structure have direct impact on expression of genetic information. Cohesin is a multi-subunit protein complex that is crucial for pairing sister chromatids during cell division, DNA repair and regulation of gene transcription and silencing. In non-plant species, cohesin is loaded on chromatin by the Scc2–Scc4 complex (also known as the NIBPL–MAU2 complex). Here, we identify the Arabidopsis homolog of Scc4, which we denote Arabidopsis thaliana (At)SCC4, and show that it forms a functional complex with AtSCC2, the homolog of Scc2. We demonstrate that AtSCC2 and AtSCC4 act in the same pathway, and that both proteins are indispensable for cell fate determination during early stages of embryo development. Mutant embryos lacking either of these proteins develop only up to the globular stage, and show the suspensor overproliferation phenotype preceded by ectopic auxin maxima distribution. We further establish a new assay to reveal the AtSCC4-dependent dynamics of cohesin loading on chromatin in vivo. Our findings define the Scc2–Scc4 complex as an evolutionary conserved machinery controlling cohesin loading and chromatin structure maintenance, and provide new insight into the plant-specific role of this complex in controlling cell fate during embryogenesis.
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
P.N.M. and E.A.M. conceptualized the project, designed and performed most of the experiments, analyzed the data, prepared figures and wrote the manuscript. S.H.R. and P.H.E. performed some experiments, E.G.-B. performed optimization of the yeast two-hybrid assay and the co-IP assay. P.V.B. participated in experimental design, discussion of results and writing of the manuscript.
Funding
This work was supported by grants from Vetenskapsrådet (Swedish Research Council; to P.N.M. and P.V.B.), Pehrssons Fund (to P.V.B.), Stiftelsen för Strategisk Forskning (Swedish Foundation for Strategic Research (to P.V.B.), Stiftelsen Olle Engkvist Byggmästare (Olle Engkvist Foundation; to P.V.B.), the Knut och Alice Wallenbergs Stiftelse (Knut and Alice Wallenberg Foundation; to P.V.B.) and the Carl Tryggers Stiftelse för Vetenskaplig Forskning (Carl Tryggers Foundation; to E.A.M. and P.N.M.).
Supplementary information
Supplementary information available online at http://jcs.biologists.org/lookup/doi/10.1242/jcs.196865.supplemental
- Received August 22, 2016.
- Accepted January 25, 2017.
- © 2017. Published by The Company of Biologists Ltd