title: Molecular identification and interaction assay of the gene (OsUbc13) encoding a ubiquitin-conjugating enzyme in rice.
abstract: The ubiquitin (Ub)-conjugating enzyme, Ubc13, has been known to be involved in error-free DNA damage tolerance (or post-replication repair) via catalyzing Lys63-linked polyubiquitin chains formation together with a Ubc variant. However, its functions remain largely unknown in plant species, especially in monocotyledons. In this study, we cloned a Ub-conjugating enzyme, OsUbc13, that shares the conserved domain of Ubc with AtUBC13B in Oryza sativa L., which encodes a protein of 153 amino acids; the deduced sequence shares high similarities with other homologs. Real-time quantitative polymerase chain reaction (PCR) indicated that OsUbc13 transcripts could be detected in all tissues examined, and the expression level was higher in palea, pistil, stamen, and leaf, and lower in root, stem, and lemma; the expression of OsUbc13 was induced by low temperature, methylmethane sulfate (MMS), and H(2)O(2), but repressed by mannitol, abscisic acid (ABA), and NaCl. OsUbc13 was probably localized in the plasma and nuclear membranes. About 20 proteins, which are responsible for the positive yeast two-hybrid interaction of OsUbc13, were identified. These include the confirmed OsVDAC (correlated with apoptosis), OsMADS1 (important for development of ﬂoral organs), OsB22EL8 (related to reactive oxygen species (ROS) scavenging and DNA protection), and OsCROC-1 (required for formation of Lys63 polyubiquitylation and error-free DNA damage tolerance). The molecular characterization provides a foundation for the functional study of OsUbc13.
authors.affiliation: Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China; Cereal Crops Institute, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Wang
authors.forename: Meng-yun
authors.initials: MY
authors.lastname: Xu
authors.forename: Jian-ping
authors.initials: JP
authors.lastname: Liu
authors.forename: Mu-gui
authors.initials: MG
authors.lastname: Wang
authors.forename: Hai-qing
authors.initials: HQ
authors.lastname: Yin
authors.forename: Ju-min
authors.initials: JM
authors.lastname: Tu
mesh_terms: D000595:Amino Acid Sequence; D008969:Molecular Sequence Data; D009685:Nuclear Envelope / Q000201:enzymology; D012275:Oryza / Q000235:genetics*; D020798:Two-Hybrid System Techniques; D044763:Ubiquitin-Conjugating Enzymes / Q000737:chemistry / Q000235:genetics* / Q000502:physiology
chemical_list: D044763:Ubiquitin-Conjugating Enzymes
keywords: DNA damage tolerance; Oryza sativa; Real-time quantitative PCR; Ubc13; Yeast two-hybrid