A SWI/SNF subunit regulates chromosomal dissociation of structural maintenance complex 5 during DNA repair in plant cells

Abstract

DNA damage decreases genome stability and alters genetic information in all organisms. Conserved protein complexes have been evolved for DNA repair in eukaryotes, such as the structural maintenance complex 5/6 (SMC5/6), a chromosomal ATPase involved in DNA double-strand break (DSB) repair. Several factors have been identified for recruitment of SMC5/6 to DSBs, but this complex is also associated with chromosomes under normal conditions; how SMC5/6 dissociates from its original location and moves to DSB sites is completely unknown. In this study, we determined that SWI3B, a subunit of the SWI/SNF complex, is an SMC5-interacting protein in Arabidopsis thialiana. Knockdown of SWI3B or SMC5 results in increased DNA damage accumulation. During DNA damage, SWI3B expression is induced, but the SWI3B protein is not localized at DSBs. Notably, either knockdown or overexpression of SWI3B disrupts the DSB recruitment of SMC5 in response to DNA damage. Overexpression of a cotranscriptional activator ADA2b rescues the DSB localization of SMC5 dramatically in the SWI3B-overexpressing cells but only weakly in the SWI3B knockdown cells. Biochemical data confirmed that ADA2b attenuates the interaction between SWI3B and SMC5 and that SWI3B promotes the dissociation of SMC5 from chromosomes. In addition, overexpression of SMC5 reduces DNA damage accumulation in the SWI3B knockdown plants. Collectively, these results indicate that the presence of an appropriate level of SWI3B enhances dissociation of SMC5 from chromosomes for its further recruitment at DSBs during DNA damage in plant cells.

LFR Physically and Genetically Interacts With SWI/SNF Component SWI3B to Regulate Leaf Blade Development in Arabidopsis

“…In the genome of the model plant, Arabidopsis thaliana , there are four Swi3 proteins, including SWI3A/3B/3C/3D ( Sarnowski et al, 2005 ). Results of a genetic analysis indicate that these components play essential roles in regulating multiple growth and developmental processes ( Sarnowski et al, 2005 ; Han et al, 2018 ; Jiang et al, 2019 ; Yang et al, 2020 ). SWI3A, SWI3B, and SWI3C proteins interact with one another, whereas SWI3D only interacts with SWI3B ( Sarnowski et al, 2005 ).…”

The SMC5/6 complex recruits the PAF1 complex to facilitate DNA double‐strand break repair in Arabidopsis

“…Furthermore, we have shown that SMC5/6 also negatively regulates cell cycle progression by inhibiting E2F transcription factors (Wang et al , 2018). Recent studies in Arabidopsis revealed that the recruitment of SMC5/6 is dependent on the IDN2–CDC5–ADA2b module (Lai et al , 2018; Jiang et al , 2019, 2022).…”

SUMOylation facilitates the assembly of a Nuclear Factor‐Y complex to enhance thermotolerance in Arabidopsis

“…In vitro pull-down and in vivo co-IP assays For the in vitro pull-down assay, the indicated proteins were produced in Escherichia coli BL21(DE3), and the assay was performed as previously described (Jiang et al, 2019). For co-IP, constructs encoding the indicated proteins were expressed in Arabidopsis or N. benthamiana leaves, and the assay was conducted as previously described (Niu et al, 2019).…”