The Arabidopsis SUMO E3 Ligase AtMMS21 Dissociates the E2Fa/DPa Complex in Cell Cycle Regulation

Chen

Proc. Natl. Acad. Sci. U.S.A.

et al. 2018

DNA damage poses a serious threat to genome integrity and greatly affects growth and development. To maintain genome stability, all organisms have evolved elaborate DNA damage response mechanisms including activation of cell cycle checkpoints and DNA repair. Here, we show that the DNA repair protein SNI1, a subunit of the evolutionally conserved SMC5/6 complex, directly links these two processes in SNI1 binds to the activation domains of E2F transcription factors, the key regulators of cell cycle progression, and represses their transcriptional activities. In turn, E2Fs activate the expression of, suggesting that E2Fs and SNI1 form a negative feedback loop. Genetically, overexpression of SNI1 suppresses the phenotypes of E2F-overexpressing plants, and loss of E2F function fully suppresses the mutant, indicating that SNI1 is necessary and sufficient to inhibit E2Fs. Altogether, our study revealed that SNI1 is a negative regulator of E2Fs and plays dual roles in DNA damage responses by linking cell cycle checkpoint and DNA repair.

Section: Loss Of E2f Function Suppresses the Sni1mentioning

confidence: 99%

Negative regulator of E2F transcription factors links cell cycle checkpoint and DNA damage repair

Chen

Proc. Natl. Acad. Sci. U.S.A.

et al. 2018

“…amino acids, from the first amino acid to the GG cleavage site) to the N terminus of NIb and then deleting the two crucial glycine residues (G92 and G93) of SUMO3 (SUMO3-ΔGG-NIb). This mutant mimics natural sumoylation of lysine residues by covalently linking SUMO to the target protein but disrupts the reversible cleavage to recycle SUMO by the desumoylation enzyme due to the deletion of the two crucial glycine residues (Ross et al, 2002;Bossis et al, 2005;Liu et al, 2016a). Wild-type NIb and SUMO3-ΔGG-NIb (both as a C-terminal YFP-tagged fusion protein) were transiently expressed in N. benthamiana leaves.…”

Section: Sumoylation Regulates the Nuclear-cytoplasmic Partitioning Omentioning

confidence: 99%

Sumoylation of Turnip mosaic virus RNA Polymerase Promotes Viral Infection by Counteracting the Host NPR1-Mediated Immune Response

et al. 2017

Sumoylation is a transient, reversible dynamic posttranslational modification that regulates diverse cellular processes including plant-pathogen interactions. Sumoylation of NPR1, a master regulator of basal and systemic acquired resistance to a broad spectrum of plant pathogens, activates the defense response. Here, we report that NIb, the only RNA-dependent RNA polymerase of (TuMV) that targets the nucleus upon translation, interacts exclusively with and is sumoylated by SUMO3 (SMALL UBIQUITIN-LIKE MODIFIER3), but not the three other SUMO paralogs. TuMV infection upregulates SUMO3 expression, and the sumoylation of NIb by SUMO3 regulates the nuclear-cytoplasmic partitioning of NIb. We identified the SUMO-interacting motif in NIb that is essential for its sumoylation and found that knockout or overexpression of SUMO3 suppresses TuMV replication and attenuates viral symptoms, suggesting that SUMO3 plays dual roles as a host factor of TuMV and as an antiviral defender. Sumoylation of NIb by SUMO3 is crucial for its role in suppressing the host immune response. Taken together, our findings reveal that sumoylation of NIb promotes TuMV infection by retargeting NIb from the nucleus to the cytoplasm where viral replication takes place and by suppressing host antiviral responses through counteracting the TuMV infection-induced, SUMO3-activated, NPR1-mediated resistance pathway.

“…5). Previous reports in Arabidopsis have found that MMS21 plays a more important role in the DNA damage repair and root development [54,55]. However, MMS21 genes were expressed poorly in nearly all tissues, indicating that the role of MMS21 in peanut is mainly possibly focused on DNA repair.…”

Section: Discussionmentioning

confidence: 93%

Defining the function of SUMO system in pod development and abiotic stresses in Peanut

et al. 2019

Self Cite

Background: Posttranslational modification of proteins by small ubiquitin like modifier (SUMO) proteins play an important role during the developmental process and in response to abiotic stresses in plants. However, little is known about SUMOylation in peanut (Arachis hypogaea L.), one of the world's major food legume crops. In this study, we characterized the SUMOylation system from the diploid progenitor genomes of peanut, Arachis duranensis (AA) and Arachis ipaensis (BB). Results: Genome-wide analysis revealed the presence of 40 SUMO system genes in A. duranensis and A. ipaensis. Our results showed that peanut also encodes a novel class II isotype of the SCE1, which was previously reported to be uniquely present in cereals. RNA-seq data showed that the core components of the SUMOylation cascade SUMO1/2 and SCE1 genes exhibited pod-specific expression patterns, implying coordinated regulation during pod development. Furthermore, both transcripts and conjugate profiles revealed that SUMOylation has significant roles during the pod development. Moreover, dynamic changes in the SUMO conjugates were observed in response to abiotic stresses. Conclusions: The identification and organization of peanut SUMO system revealed SUMOylation has important roles during stress defense and pod development. The present study will serve as a resource for providing new strategies to enhance agronomic yield and reveal the mechanism of peanut pod development.