Rice UBC13, a candidate housekeeping gene, is required for K63-linked polyubiquitination and tolerance to DNA damage

Abstract

While plant growth and reproduction is dependent on sunlight, UV irradiation from sunlight is one of the major genotoxic stresses that threaten plant survival and genome stability. In addition, many environmental chemicals can also damage the plant genome. In yeast and mammalian cells protection against the above genome instability is provided by an error-free DNA-damage tolerance (DDT) pathway, which is dependent on Ubc13-mediated K63-linked polyubiquitination of the proliferating cell nuclear antigen (PCNA). In this study, we isolated the UBC13 gene from rice and characterized its functions. Expression of OsUBC13 can protect a yeast ubc13 null mutant against spontaneous and environmental DNA damage. Furthermore, OsUbc13 physically interacts with human Ubc13 partners Mms2 and Uev1A, and catalyzes K63 polyubiquitination in vitro. These observations collectively suggest that the K63 polyubiquitination is conserved in rice, and that OsUBC13 may be involved in DDT and other cellular processes. In addition, OsUBC13 is constitutively expressed at a high level even under various stress conditions, suggesting that it is a housekeeping gene.Electronic supplementary materialThe online version of this article (doi:10.1186/1939-8433-5-24) contains supplementary material, which is available to authorized users.

Characterization of four rice UEV1 genes required for Lys63-linked polyubiquitination and distinct functions

“…Functional studies indicate that these rice UEV genes can restore cellular activity of the yeast mms2 null mutant for resistance to a DNA-damaging agent, reminiscent of the ability of OsUBC13 to restore the corresponding yeast ubc13 mutant [28]. Furthermore, several observations are consistent with the notion that the four OsUEV1 s confer different functions in vivo.…”

Proteasome‐independent functions of lysine‐63 polyubiquitination in plants

“…Plants have expanded their repertoire of UBC13/ UEV1 genes compared with yeast or mammals, potentially allowing diversification in spatiotemporal expression pattern, Ub transfer activity or ability to interact with the myriad of E3s found in plants. Homologs of UBC13 and UEV1 have also been characterized in other plants, such as rice, tomato and Brachypodium (Zang et al, 2012;Mural et al, 2013;Hamera et al, 2014;Wang et al, 2014;Guo et al, 2015Guo et al, , 2016. Global analysis of the Arabidopsis E2 family and its ability to interact with a subset of 45 RING E3s revealed that both AtUBC13A and AtUBC13B bind in vitro to the same E3s from the RING-HCa and RING-H2 types (Kraft et al, 2005).…”

“…In addition, treatment with MMS induces BdUEV1B expression, suggesting a role of these two UEV1s in the DNA damage response. UBC13 and UEV1 variants from other plant species have been characterized recently and shown to complement the sensitivity of the ubc13 or mms2 yeast mutant to DNA damaging agents, revealing a widespread mechanism of DNA repair involving K63 chains among eukaryotes (Zang et al, 2012;Guo et al, 2015Guo et al, , 2016. The AtUBC13-interacting AtRGLG1 and AtRGLG2 E3 ligases are also involved in DNA damage responses, as the rglg1/rglg2 mutant is hypersensitive to MMS (Pan & Schmidt, 2014).…”

Conventional and unconventional ubiquitination in plant immunity

“…Nevertheless, available data hitherto suggest that they play key regulatory roles in plants. For example, K63‐linked ubiquitination regulates DNA replication and repair, protein synthesis, the iron deficiency response and immune signalling (Hamera et al ., ; Li and Schmidt, ; Mural et al ., ; Wen et al ., ; Zang et al ., ). Moreover, monoubiquitination of the histone H2B is crucial for the transcriptional regulation of key regulators in plant flowering, seed dormancy and plant immunity (Du et al ., ; Feng and Shen, ; Hu et al ., ; Zhang Y et al ., ; Zou et al ., ).…”