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| 購(gòu)買進(jìn)口儀器、試劑和耗材——就在始于2001年的畢特博生物 www.kjhfd.cn |
雙生病毒(Geminivirus)是一組具有雙生顆粒形態(tài)的單鏈環(huán)狀植物DNA病毒。由于雙生病毒主要依賴于植物宿主系統(tǒng)來(lái)完成生活史，能夠通過(guò)自身編碼的少數(shù)幾個(gè)蛋白來(lái)調(diào)控植物的若干重要生命過(guò)程，因此，對(duì)雙生病毒展開深入研究，有助于揭示植物自身若干重要生命過(guò)程的分子機(jī)制。另外，雙生病毒侵染廣泛的農(nóng)作物，造成農(nóng)作物的嚴(yán)重減產(chǎn)，因此研究植物與雙生病毒的相互作用機(jī)制能夠?yàn)榛蚬こ趟礁牧嫁r(nóng)作物、提高農(nóng)作物抗病毒能力提供有力的理論依據(jù)。目前的研究已經(jīng)表明，植物能夠通過(guò)多種手段抵御病毒的侵染，例如基因沉默信號(hào)途徑、水楊酸信號(hào)途徑以及代謝調(diào)控途徑等；病毒也在與植物的協(xié)同進(jìn)化過(guò)程中，通過(guò)編碼的少數(shù)幾個(gè)蛋白調(diào)節(jié)植物的相應(yīng)生命過(guò)程來(lái)與植物宿主相抗衡。 中科院遺傳與發(fā)育生物學(xué)研究所謝旗實(shí)驗(yàn)室采用反向遺傳學(xué)策略，結(jié)合分子生物學(xué)和生物化學(xué)等方法，發(fā)現(xiàn)雙生病毒甜菜嚴(yán)重曲頂病毒（Beet Severe Curly Top Virus, BSCTV）能夠通過(guò)編碼的C2蛋白與植物宿主蛋白腺苷甲硫氨酸脫羧酶1（S-adenosyl-methionine decarboxylase 1，SAMDC1）相互作用，并抑制26S蛋白酶體介導(dǎo)的SAMDC1蛋白降解。功能研究發(fā)現(xiàn)，C2蛋白對(duì)植物宿主蛋白SAMDC1的這一正調(diào)控過(guò)程能夠影響植物宿主對(duì)自身基因以及病毒基因組的從頭甲基化過(guò)程，進(jìn)而影響植物宿主基因沉默介導(dǎo)的抗病毒防御反應(yīng)和病毒DNA在植物宿主中的積累。 該研究結(jié)果反映了病毒與植物寄主在長(zhǎng)期協(xié)同進(jìn)化過(guò)程中的其中一種博弈場(chǎng)面，也揭示了SAMDC1在甲基化介導(dǎo)的基因沉默途徑中的重要作用，對(duì)詮釋26S蛋白酶體介導(dǎo)的蛋白降解途徑調(diào)節(jié)通過(guò)調(diào)控寄主de novo甲基化介導(dǎo)的基因沉默信號(hào)過(guò)程具有重要意義。該研究也為植物抗病毒提供了新理論和新策略。 該研究在線發(fā)表于2011年1月的Plant Cell雜志上，并得到了雜志的推薦導(dǎo)讀。謝旗實(shí)驗(yàn)室的博士生張鐘徽為該論文的第一作者。 該項(xiàng)目得到了國(guó)家自然科學(xué)基金和蛋白重大專項(xiàng)項(xiàng)目的資助。 推薦原文出處： Plant Cell DOI:10.1105/tpc.110.081695 BSCTV C2 Attenuates the Degradation of SAMDC1 to Suppress DNA Methylation-Mediated Gene Silencing in Arabidopsis[W],[OA] Zhonghui Zhang,Hao Chen,Xiahe Huang,Ran Xia,Qingzhen Zhao,Jianbin Lai,Kunling Teng,Yin Li,Liming Liang,Quansheng Du,Xueping Zhou,Huishan Guo,and Qi Xie Abstract Plant viruses are excellent tools for studying microbial–plant interactions as well as the complexities of host activities. Our study focuses on the role of C2 encoded by Beet severe curly top virus (BSCTV) in the virus–plant interaction. Using BSCTV C2 as bait in a yeast two-hybrid screen, a C2-interacting protein, S-adenosyl-methionine decarboxylase 1 (SAMDC1), was identified from an Arabidopsis thaliana cDNA library. The interaction was confirmed by an in vitro pull-down assay and a firefly luciferase complemention imaging assay in planta. Biochemical analysis further showed that the degradation of the SAMDC1 protein was inhibited by MG132, a 26S proteasome inhibitor, and that C2 could attenuate the degradation of the SAMDC1 protein. Genetic analysis showed that loss of function of SAMDC1 resulted in reduced susceptibility to BSCTV infection and reduced viral DNA accumulation, similar to the effect of BSCTV C2 deficiency. Bisulfite sequencing analysis further showed that C2 deficiency caused enhanced DNA methylation of the viral genome in infected plants. We also showed that C2 can suppress de novo methylation in the FWA transgenic assay in the C2 transgene background. Overexpression of SAMDC1 can mimic the suppressive activity of C2 against green fluorescent protein–directed silencing. These results suggest that C2 interferes with the host defense mechanism of DNA methylation-mediated gene silencing by attenuating the 26S proteasome-mediated degradation of SAMDC1. |
購(gòu)買進(jìn)口儀器、試劑和耗材——就在始于2001年的畢特博生物
www.kjhfd.cn |
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