title: The function of Rad6 gene in Hevea brasiliensis extends beyond DNA repair.
abstract: The Rad6 gene of Saccharomyces cerevisiae encodes an ubiquitin-conjugating enzyme (E2) which is required for DNA repair, damage-induced mutagenesis, sporulation, etc. In this study, one Rad6 homolog, designated HbRad6, was cloned in rubber tree (Hevea brasiliensis). The putative protein sequence of HbRad6 contains 152 amino acids, a conserved UBC domain, and a conserved active-site cysteine in the UBC domain, which is required for E2 enzymes catalytic activity. HbRad6 shared high similarity with Rad6 from other species. It shared the highest similarity with rice OsRad6 and Arabidopsis thaliana AtUBC2 with 96.05% identical residues, and 63.16% sequence identity with yeast Rad6 (excluding the acidic tail). Comparing expression among different Hevea tissues demonstrated that HbRad6 was ubiquitously expressed in all tissues, but it revealed a preferential expression in the latex. Furthermore, HbRad6 expression was markedly induced by DNA-damaging agent H2O2, the latex stimulator ethephon (ET), and methyl jasmonate (MeJA), while NaCl and wounding treatments had relatively minor effect upon its expression. Genetic complementation experiment revealed that HbRad6 had minor effects on the complementation of the UV sensitivity of yeast rad6 null mutant, indicating that the Hevea Rad6 protein may partially suppress the UV sensitivity of the yeast rad6 mutant. These results suggested that HbRad6 was a multifunction gene involved in DNA damage repair, hormones and stress responses in rubber tree.
authors.affiliation: Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, China. qinbi126@163.com
authors.forename: Bi
authors.initials: B
authors.lastname: Qin
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003517:Cyclopentanes / Q000494:pharmacology; D004249:DNA Damage; D004260:DNA Repair; D019143:Evolution, Molecular; D005786:Gene Expression Regulation / Q000187:drug effects; D017343:Genes, Plant; D005816:Genetic Complementation Test; D028482:Hevea / Q000235:genetics* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009943:Organophosphorus Compounds / Q000494:pharmacology; D054883:Oxylipins / Q000494:pharmacology; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D012965:Sodium Chloride / Q000494:pharmacology; D013314:Stress, Mechanical; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D009943:Organophosphorus Compounds; D054883:Oxylipins; D010940:Plant Proteins; D029701:Saccharomyces cerevisiae Proteins; D012965:Sodium Chloride; C072239:methyl jasmonate; D006861:Hydrogen Peroxide; C471606:RAD6 protein, S cerevisiae; D044763:Ubiquitin-Conjugating Enzymes; C005073:ethephon