Molecular cloning and functional characterization of Physcomitrella patens UBC13-UEV1 genes required for Lys63-linked polyubiquitination. (August 2020)

• Record Type: Journal Article
• Authors: Guo, Huiping; Wang, Linxiao; Hu, Ruoyang; He, Yikun; Xiao, Wei
• Is Part Of: Plant science. Volume 297(2020)
• Publication Date: 2020-08
• Subjects: Physcomitrella patens -- Ubc13 -- Uev1 -- K63-linked polyubiquitination -- DNA-damage tolerance; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2020.110518
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: Two UBC13 and three UEV1 genes were cloned and characterized from P. patens . These gene products are required for Kys63-linked polyubiquitination. These genes can functionally complement the corresponding yeast mutants except PpUEV1A . After a C-terminal truncation and a single amino acid substitution, PpUev1A is able to function like other UEVs. Plant UEV1 gene duplication and functional diversification appeared to emerge from mosses. Abstract: Ubc13 and Ubc/E2 variant (Uev) form a stable heterodimer to mediate Lys63-linked polyubiquitination. Unicellular eukaryotic genomes often contain single UBC13 and UEV gene; however, multiple homologs were found in higher plants. As initial land plants, Physcomitrella patens occupies a key evolutionary position between green algae and higher plants. In this study, we report the identification and functional characterization of two UBC13 and three UEV1 genes from P. patens . Both PpUbc13s form heterodimers with PpUev1B or PpUev1C, which catalyze Lys63-linked polyubiquitination in vitro and functionally complement the yeast ubc13 mms2 null mutant from killing by DNA-damaging agents. In contrast, PpUev1A is unable to interact with Ubc13s and cannot complement the yeast mms2 mutant. Two single mutations, PpUev1A-D12N and ΔCT, barely have any effect; however, the corresponding double mutation makes PpUev1A functional in both heterodimer formation and complementation. This study identifies a critical Uev residue located in the Ubc13-Uev interface and reveals that mosses began to evolve multiple UBC13 and UEV orthologs in order to adapt to the terrestrial environment. The evolutionary significance of PpUEV1A is discussed.