2016年9月22日，國際核酸類重要學術(shù)期刊《Nucleic Acids Research》雜志在線發(fā)表了中國科學院華南植物園區(qū)永祥研究組的一篇研究論文，研究在氧化脅迫耐受基因(OXIDATIVE STRESS )研究方面取得新進展。華南植物園博士后何玉梅為論文第一作者，區(qū)永祥研究員為論文通訊作者。
環(huán)境脅迫導致作物減產(chǎn)，生物脅迫和非生物脅迫都會擾亂細胞代謝平衡，引起細胞內(nèi)活性氧水平升高，進而導致細胞損傷和死亡。區(qū)永祥研究團隊一直致力于解析植物在應答引起氧化損傷的重金屬脅迫過程中的分子機理。研究人員在裂殖酵母中闡明了一條新的鎘誘導的二硫化物脅迫調(diào)控途徑——Oxs1-Pap1途徑。該途徑在真核細胞中高度保守。來源于人類、老鼠、擬南芥中異源蛋白Oxs1和Pap1蛋白在體外均可發(fā)生互作，這些異源蛋白質(zhì)在裂殖酵母中可提高鎘的脅迫性。推測Oxs1參與調(diào)控生物體內(nèi)保守的脅迫調(diào)控途徑。
實驗前期研究發(fā)現(xiàn)擬南芥OXS2基因作為一個轉(zhuǎn)錄因子調(diào)控植物脅迫逃逸。華南植物園博士賀立龍等科研人員在對玉米的研究中發(fā)現(xiàn)玉米OXS2家族通過激活一個甲基轉(zhuǎn)移酶樣基因，進而提高植物對重金屬鎘的抗性。研究成果題為“Maize OXIDATIVE STRESS2 Homologs Enhance Cadmium Tolerance in Arabidopsis through Activation of a Putative SAM-Dependent Methyltransferase Gene1”。
擬南芥中OXS3蛋白很可能作為一個組蛋白修飾因子，從而響應重金屬脅迫和氧化脅迫。華南植物園助理研究員王昌虎等科研人員通過表達水稻中OXS3基因家族成員，可以顯著降低水稻谷粒中的鎘含量。由于中國耕地污染問題，導致近年來出現(xiàn)了許多高鎘稻米產(chǎn)品。土壤修復等手段不能在短期內(nèi)有效解決這一問題，因此通過創(chuàng)制低鎘累積水稻新種質(zhì)為保障糧食安全提供了新的解決方案。研究成果題為“Reduction of Cd in Rice through Expression of OXS3-like Gene Fragments”。
原文鏈接：
A Pap1–Oxs1 signaling pathway for disulfide stress in Schizosaccharomyces pombe
原文摘要：
We describe a Pap1–Oxs1 pathway for diamide-induced disulfide stress inSchizosaccharomyces pombe, where the nucleocytoplasmic HMG protein Oxs1 acts cooperatively with Pap1 to regulate transcription. Oxs1 and Pap1 form a complex when cells are exposed to diamide or Cd that causes disulfide stress. When examined for promoters up-regulated by diamide, effective Pap1 binding to these targets requires Oxs1, and vice versa. With some genes, each protein alone enhances transcription, but the presence of both exerts an additive positive effect. In other genes, although transcription is induced by diamide, Oxs1 or Pap1 plays a negative role with full de-repression requiring loss of both proteins. In a third class of genes, Oxs1 positively regulates expression, but in its absence, Pap1 plays a negative role. The Oxs1–Pap1 regulatory interaction appears evolutionarily conserved, as heterologous (human, mouse andArabidopsis) Oxs1 and Pap1-homologues can bind interchangeably with each other in vitro, and at least in the fission yeast, heterologous Oxs1 and Pap1-homologues can substitute for S. pombe Oxs1 and Pap1 to enhance stress tolerance.
