第36卷第4期 201 2年7月 水生生物学报 ACTA HYDROBIOLOGICA SINICA Vo1.36,NO.4 Ju1.. 2 0 l 2 D0I:10.3724/SPJ.1035.2012.00640 雨生红球藻质体球滴结构蛋白基因的克隆与原核表达 范 勇 于广欣2 汪乐霓 曲芳兵 冷 鹂 兰利琼 卿人韦 (1.四川大学生命科学学院,成都610065;2.中海油新能源投资有限责任公司,北京 100016) 摘要:叶绿体或者有色体中的质体球滴结构(Plastoglobules)是多数植物的类胡萝卜素等次生代谢产物积累的 场所,但在能大量积累虾青素的雨生红球藻中,这个结构一直没有得到确认。通过透射电子显微镜观察发现 雨生红球藻的质体内确切存在plastoglobules结构;并通过RT-PCR结合RACE技术,从雨生红球藻cDNA 文库中克隆到了与编码plastoglobules的结构蛋白(Plastoglobulin)具有高度同源性的基因序列全长,称做 Hpgp基因;该基因的表达产物称之为雨生红球藻质体球滴蛋白(HPGP;Haematococcus plastoglobules pro— tein);并进一步利用原核表达系统将该编码基因进行原核诱导表达,用His.Tag蛋白分离纯化系统纯化到了 目标蛋白,并用该His.Tag融合蛋白为抗原免疫实验兔,制备到了相应的一抗抗体,为下一步对该蛋白的功 能阐明以及雨生红球藻的虾青素积累机制研究提供重要的基础。 关键词:雨生红球藻;虾青素;质体球滴;基因克隆;原核表达;抗体 中图分类号:Q781 文献标识码:A 文章编号:1000-3207(2012)04-0640-06 虾青素是一种具有极强抗氧化活性的类胡萝卜 谢过程而被人们关注L2引。 雨生红球藻能够大量积累虾青素,但关于虾青 素的积累结构并没有得到深入的阐述[3,24,25】。根据对 虾青素的性质以及plastoglobules结构积累物质的比 较,发现雨生红球藻的虾青素积累也可能存在于类 素,具有广泛的应用价值。单细胞绿藻雨生红球藻在 环境胁迫条件下可以合成和积累虾青素高达细胞干 重的4%,成为目前首选的天然虾青素合成来源L1 ]。 早期的研究证实雨生红球藻在叶绿体中合成虾青素 的前体[6--8】,并大量积累虾青素在胞质中的虾青素 球滴中[ , 】。但是在大多数植物中,类胡萝卜素类物 质积累于叶绿体或者有色体的质体球滴(Plastoglo— bules)结构中[】卜 】。Plastoglobules结构已被证明是 植物中类胡萝卜素代谢和储存的重要场所,目前对 plastoglobules结构的研究还在不断深人 "1”。 Plastoglobules结构除了含有脂质及次生代谢产物外, 还含有许多蛋白质。其中,plastoglobulin蛋白家族是 特异性的结合在plastoglobules结构上的蛋白[22]o另 似plastoglobules的结构中。研究雨生红球藻是否含 有plastoglobulin蛋白不仅可以揭示虾青素的积累结 构及积累机制,也会对将来的虾青素生产提供优化 的手段和依据。为了对此假设进行研究,我们首先 通过电子显微镜观察,发现雨生红球藻的质体内也 存在plastoglobules结构。在分子水平上,从已建立 的雨生红球藻cDNA文库中,鉴定出一个相关基因 片段,并通过RACE技术克隆到了该基因全长,并 将其命名为Hpgp(Haematococcus plastoglobules 外,近期的研究还发现在plastoglobules结构中含有 protein)。该基因的表达产物我们称之为雨生红球藻 次生代谢产物合成相关的酶,因此,plastoglobules 结构除了具有储存作用外,还参与了相关物质的代 质体球滴蛋白(HPGP),并通过生物信息学分析证 实其与已知植物质体内次生代谢产物积累结构 收稿日期:2Ol1—09—20;修订日期:2012-04—16 基金项目:国家高技术发展计 ̄(863计划)(20o7AA09z427);国家自然科学基金面上项目(40976092);四川省科技厅应用基础项 目(2008JY0030)资助 作者简介:范勇(1983一),男,山东济南人;硕士研究生;主要从事微藻次生代谢产物开发和能源微藻开发工作。E—mail:fanyong @qibebt.ac.cn 通讯作者:卿人韦,E—mail:qingrw@SCU.edu.cn 4期 范 勇等:雨生红球藻质体球滴结构蛋白基因的克隆与原核表达 641 plastoglobules相关蛋白plastoglobulin有37%一45% 的相似性。并且雨生红球藻HPGP同样存在定位于 质体的前导肽。利用原核表达系统得到了HPGP的 成熟蛋白,并制备了特异性的抗体,为后续研究奠 定基础。 1材料与方法 1.1藻种及培养方法 雨生红球藻(Haematococcus pluvialis Flotow NIES一1 44)来自日本的the National Institute for En. vironmental Studies(NIES)。培养基使用Kobayashi et a1.改良的配方[ ,。 ,(醋酸钠:1.20 g/L;酵母提取 物:2.00 g/L;L一天冬氨酸:0.40 g/L;MgC12‘6H2O:0.20 g/L;FeSO4‘7H20:0.01 g‘/L;CaC12‘2H20:0.02 g/L, pH=6.8)。雨生红球藻培养于(22il) ̄C,50 i.tmol/(m2'S) 光照强度下12h/12h的光暗周期,用于同步化处理, 细胞进入对数生长期后,100 gmol/(rn2・s)光照强度下 进行光胁迫。 1.2透射电镜检测 50 mL对数生长期的细胞经过48h光照胁迫后、 低速离心收集,PBS缓冲液洗2次,固定于2%的多 聚甲醛和0.2%的戊二醛中,4+C下放置45min。低速 离心后倒掉固定液,PBS缓冲液洗2次。然后加入 1%四氧化锇固定液在4℃下固定2h。30%、50%、 70%的丙酮各脱水10min,70%乙醇饱和醋酸铀溶液 中染色过夜(4℃),90%的丙酮脱水10min,100%的 丙酮脱水2次,每次10min,Epon 812环氧树脂包埋 液与100%的丙酮按1:1加入进行渗透,37 ̄C放置 过夜。渗透完成后,将样品置于包埋模具中,加入新 鲜的Epon812包埋液。45℃下聚合12h,60℃下再聚 合12h。样品包埋聚合后,进行超薄切片,常规铅铀 染后,电镜观察。 1.3 RNA提取及RT.PCR扩增目的基因片段 将光照胁迫24h的细胞4000 r/min离心收集, 迅速液氮研磨,使用植物小量RNA提取试剂盒(上 海华舜生物技术公司)进行提取,实验操作参照试剂 盒说明。将提取的RNA立即进行反转录。 使用已知的3种植物的plastoglobulin蛋白家族 蛋白序列『P8047 1(Solanum tuberosum);Q42493 (Capsicum annuum);Q96398(Cucumis sativus)】,通 过tblastn与本实验室建立的雨生红球藻cDNA文库 中的序列进行比对,选择E值小于10 的片段作为 疑似的雨生红球藻plastoglobulin蛋白的EST序列。 设计特异性引物,HPGP1:5 .CCGCAGCATCC CTACGCGCTT一3 :HPGP2:5'-GATCATCGTCGGC GTAGGTGGTCA.3 。以HPGP1和HPGP2为引物, 以cDNA为模板进行PCR扩增[PCR反应:94 ̄C 5min; 35个循环(90℃30s,55℃30s,72 ̄C 2min);72 ̄C保持 10min]。PCR产物进行琼脂糖电泳,并且胶回收目 的片段。 1.4 雨生红球藻plastoglobulin蛋白基因cDNA全 长的克隆1 。一 。 3 末端扩增(3 RACE) 用两个套合的PCR完 成,即第一个锚定PCR和一个Nested—PCR,分别设 计三条引物,即3RRT(用于锚定polyA):5-GCTGT CAACGATACGCTACGTAACGGCATGACAGTGT 一3 :3RNP(用于Nested—PCR) 5'-TACGTAACGGCATGACAGTG.3 和HPGP3(用 于Nested—PCR):5'-GTATGGCACTGAGCGTGGCT TGAC-3 。 以3RRT和HPGP1为引物做第一轮PCR,然后 将PCR产物稀释10倍,以HPGP3和3RNP为引物 做第二轮PCR,将PCR条带回收,进行测序。 5 末端扩增(5 RACE) 根据测序得到的中 间片段设计基因上的特异性引物(5R:5'-GATCAC GCTGTTCACCTGGCTCAC.3 )进行反转录,醋酸钠 沉淀反转录产物,以去除反应体系中的酶,再用少 量ddH O溶解。用末端连接酶(TDT)在其3 末端加 上polyA。再以加过polyA的cDNA为模板,以锚定 引物5RRT(用于锚定polyA)和5R进行第一轮扩增 f5RRT:5 一CGCTACGTAACGGCATGACAGTGTTT TTTTTTTTTTv.3 1。将第一轮的PCR产物稀释8 倍,接着以基因上的特异性引物5RN和5RNP(用于 Nested.PCR)做第二轮PCR(5RN:5'-GGACCACCTT GTTTTCCACAG・3 :5RNP:5'-TACGTAACGGCAT GACAGTG.3 )。将PCR条带回收,进行测序。 全长序列的生物信息学分析 蛋白质的功能 区由NCBI的保守结构域(CDD)数据库(http://www. ncbi.nlm.nih.gov/Structure/cdd/cdd.shtm1)进行预 测。采用DNAMAN软件进行氨基酸多序列比对,比 对序列包括:『Capsicum annuum中Fibrillin蛋白[¨,H ; Cucumis sativus由CHRC(carotenoid-associated pro— tein)蛋白[131;Citrus unshiu Marc中CitPAP蛋白 ; P&um sativum L中PG1(plastoglobulin1)蛋白I ; Solanum tuberosum中CDSP34(chloroplastic drought- induced stress protein)蛋白 , ;Arabidopsis thaliana 644 水 生 生 在雨生红球藻含虾青素的球滴中发现了一个特异的 蛋白HOGP(Haematococcus Oil Globule Protein),这 个蛋白基因的转录水平与雨生红球藻在胁迫条件下 积累虾青素的量成正比【3 l。大量文献证明雨生红球 藻虾青素的合成和积累分别存在于质体和胞质中, plastoglobules中的HPGP蛋白和胞质中的虾青素球 滴的HOGP蛋白,可能分别是两个不同阶段的主要 结构蛋白,在虾青素合成过程的过膜阶段存在着功 能的对接。本文通过原核表达融合蛋白制备了HPGP 蛋白的特异性抗体,为今后进行免疫杂交实验和免 疫胶体金细胞内标记实验提供了基础。 参考文献 [1] Kobayashi M,Kakizono T'Nagai S.Enhanced carotenoid biosynthesis by oxidative stress in acetate induced cystcells of a green unicellulra alga Haematococcus pluvialis[J].Ap- pliedandEnvironmental Microbiology,1993,59:867—873 【2】 Boussiba S,Wang B,Yuan P et a1.Changes in pigments profile in the green alga Haematococcus pluvialis exposed to environmental stresses[J].Biotechnology Letters,1999,21: 601--604 【3】 Boussiba S.Carotenogenesis in the green alga Haema— tococcus pluvial&:cellulra physiology and stress response [J]_Plant JP iology,2000,108:l1 1一l17 [4】 Sarada R,Usha L Ravishankar G A.Influence of srtess on astaxanthin production in Haematococcus pluvialis grown under different culture conditions[J].Process Biochemistry, 2002.37:623—627 [5] Wang M,Li L Li A F,et a1.Effect oflighting,temperature and pH on photosynthetic characters of Haematococcus plu— vialis CG-1 1[J]_Acta Hydrobiologica Sinica,2009,33(3): 400--405[王铭,李涛,李爱芬,等.光照、温度和pH对 雨生红球藻光合特性的影响.水生生物学报,2009,33(3): 40o_一4O5】 【6】 GrOnewald K,Hirschberg J,Hagen C.Ketocarotenoid bio— synthesis outside of plastids in the unicellular green alga Haematococcus pluvialis[J】.Journal ofBiological Chemis— try,2001,276:6023--6029 [7】 G ̄newald K,Hagen C.beta・carotene is the intermediate exported from the chloroplast during accumulation of sec— ondary carotenoids in Haematococcus pluvialis[J].Journal foAppliedPhycology,2001,13(1):89—93 【8】 Collins A M,Jones H D Tj Han D X,et a1.Carotenoid dis— tribution in living cells of Haematococcus pluvialis (Chlorophyceae)[J】.Plos One,2011,6(9):e24302 【9] Griinewald K,Hagen C.Extrusion of secondary carotenoid containing vesicles from flagellates of Haematococcus plu— vialis(Volvocales;Chlorophyceae)[J].Journal of Applied Botany—Angewandte BotaniL 2000,74(3-41:l41—144 [10】Santos M F’Mesquita J F Ultrastructural study of Haema— 物 学 报 36卷 tococcus lacustris(Girod)Rostafinski(Volvocales).1.Somea— spects ofcarotenogenesis[J].Cytologia,1984,49:215—228 [11]Deru6re J,Romer S,d,Harlingue A,et a1.Fibrn assembly and carotenoid overaccumulation in chromoplasts:a model for supramolecular lipoprotein strucutres[J】.Plant Cell, 1994.6:l19—133 [12]Katz A,Jim6nez C,Pick U.Isolation and characterization of a protein associated wiht carotene globules in the alga Du— naliella bavdawil[J].Plant Physiology,1995,108:1657— 1664 [13]Vishnevetsky M,Ovadis M,Itzhaki H,et a1.Molecular cloning of a carotenoid--associated protein from Cucum&sa-- tivus corollas:homologous genes involved in carotenoid se— questration in chromoplasts[J].Plant Journal,1996,10: l1l1一l118 [14】Pozueta—Romero J,Rafia F,Houlne G et a1.A ubiquitous plant housekeeping gene,PAP,encodes a major protein component of bell pepper chromoplasts[J].Plant P iology, 1997.115:l185—1194 [15]Emanuelsson O,Nielsen H,von Heijne G ChloroP,a neural network-based method for predicting chloroplast transit pep- tides and their cleavage sites[J].Protein Science,1 999,8: 978—984 【16]Kessler F,Schnell D,Blobel G Identiifcation of proteins associated with plastoglobules isolated from pea(Pisum so— tivum L.)chloroplasts[J】.Planta,1999,208:107--113 [17】Kim H U,Wu S H,Ratnayake C,et a1.Brassica rapa has three genes that encode proteins associated with different neutral lipids in plastids of speciifc tissues[J].Plant Physi— ology,2001.126:330—341 [18】Br6h61in C,Kessler F’van Wijk K J.Plastoglobules:versatile lipoprotein particles in plastids【J].Trends in Plant Science, 2007.12:260—266 [19]Kessler E Vidi R Plastoglobule lipid bodies:their functions in chloroplasts and their potential for applications【J]. vances in Biochemical Engineering/Biotechnology,2007, 107:153—172 [20】Br6h61in C,Kessler F.The plastoglobule:a bag full of lipid biochemistry tricks[J].Photochemistry and Photobiology, 2008.84:1388—1394 【21]Singh D K,McNellis T W.Fibrillin protein function:the tip of the iceberg[J]?Trends in Plant Science,2011,16(8): 432—441 [22】Laizet Pontier D,Mache R,et a1.Subfamily organization nad phylogenetic origin of genes encoding plastid lipid-・as-- sociated proteins of hte ifbrillin type[J].Journal fo Genome Science and Technology,2004.3:17--26 [23]Ytterberg A J,Peltier J B,van Wijk K J.Protein profiling of plastoglobules in chloroplasts and chromoplasts.A surprising site for differential accumulation of metabolic enzymes . PlantPhysiology,2006.140:984—997 [24]Jin E,Lee C G Polle J E w Secondary carotenoid accumula— tion in Haematococcus(Chlorophyceae):biosynthesis,regu— lation,and biotechnology[J】.Journal of Microbiology and Biotechnology.2006.16:821—83 1 4期 范勇等:雨生红球藻质体球滴结构蛋白基因的克隆与原核表达 645 [25]Vidhyavathi R,Sarada R,Ravishankar G A.Expression of carotenogenic genes and carotenoid production in Haemato— 334—338 [32】Pruvot G Cuine S,Peltier G’et a1.Characterization of a novel drought・-induced 34—-kD a protein located in the thyla・- coccus pluvial ̄under the influence of carotenoid and fatty acid synthesis inhibitors[J]_Enzyme and Microbial Tech— nology,2009,45(2):88—93 [26]Kobayashi M,Kakizono Nagai S.Astaxanthin production by a green alga,Haematococcus pluvialis,accompanied with koids ofSolanum tuberosum L.[J】.Planta,1996,198:471— 479 [33]Gillet B,Beyly A,Peltier G el a1.Molecular characterization of CDSP34,a chloroplastic protein induced by water deficit in Solanum tuberosum L.plants,and regulation of CDSP34 morphological changes in acetate media[J]_Journal ofFer- mentation andBioengineering,1991.71:335—339 expression by ABA and high illumination[J】.Plant Journal 1998.16:257—262 【27]Lombardo M E,Araujo L S,Juknat A A,et a1.Effect of illumination on growth,chlorophyll content and 8-amino- [34】Friso G Giacomelli L,Ytterberg A J,et a1.In—depth analysis of he tthylakoid membrane proteome ofArabidopsis thaliana chloroplasts:new proteins,new functions,and a plastid pro— levulinic acid synthesis in Euglena gracilis[J].Comparative Biochemistry and Physiology pnn B:Comparative Bioche— misty,1988,9l(r2):279—284 teome database[J】_Plant Cell 2004,16:478—499 【28]Borson N D,Sato W L,Drewes L R.A lock—dock ing oligo (dT)primer for 5’and 3’RACE PCR[J]_PCR Methods and Applications,1992.2:144—148 [351 Schmidt M,Ge ̄ner G Luff M,et a1.Proteomic analysis of the eyespot of Chlamydomonas reinhardtii provides novel insights into its components nd atactic movements[J].Plant Ce 2006,18:l9O8—1930 【29】Fehr C,Fickov M,Hiemke C,et a1.Rapid cloning of eDNA ends polymerase chain reaction of G-protein—coupled recep [36】Coligan J E.Short Protocols in Protein Science[M】.New York:JohnWiley&Sons.2003 to r kinase 6:an improved method to determine 5’一and 3'-eDNA ends[J].Brain Research ProtocoIs,1999,3(3): 242—251 [37]Sambrook J,Russell D W Moleculra Cloning:A Laboratry Manual[M].Cold Spring Harbor Lab(CSHL)Press.2001 [38]vidi P A,Kanwischer M,Baginsky S,et a1.Tocopherol cy— clase(VTE1)localization and vitaminE accumulation in chloroplast plastoglobule lipoprotein particles[J].Journal of Biological Chemisty,2006.281:l1225一lr 1234 [30]Fang C,Mkrtchian S,Sundberg M.Combination of direct DNA sequencing with degenerate pri mer-mediated PCR and 5’一/3’-RACE to screen novel cDNA sequences[J].Bio— techniques,1997,23(1):52—58 [3 1]Moriguchi Kita M,Endo-Inagaki L et a1.Characterization of a eDNA homologous to carotenoid—associated protein in [39]Peled E,Leu S,Zarka A,et a1.Isolation of a novel oil glob・ ule protein from the green alga Haematococcus pluvialis citrus fruits[J]_Biochimica el Biophysica Acta,1 998,1442: (Chlorophyceae)[J】. ids,2011,46(9):851—861 CLoNING AND PRoKARYoTIC EXPRESSION OF THE PLASTOGLOBULES PRoTEIN GENE FRoM月 E CDC C 【 咒 三 FAN Yong ,YU Guang.Xin ,WANG Le—Ni ,QU Fang.Bing ,LENG Li ,LAN Li.Qiong and QING Ren.Wei (1.School ofLife Sciences,Sichuan University,Chengdu 6 1 0065,China; 2.CNOOCNewEnergyInvestmentCo.,Ltd.,Beijing 100016,China) Abstraet:Carotenoids were organized in plastoglobules located in the interthylakoid space of the chloroplast for many plants.However,the plastoglobule,a carotenoid deposit structure in chromoplast,was not clear in ematococcus pluvialis yet up to date.In the present study,many osmiophilic globuli appeared in both the chromoplast and cytoplasm of pluvialis under electron microscopy with a modiied fmethod.Those revealed clearly the presence of plastoglobules in the chloroplast of/4.pluvialis.A ful1.1ength cDNA was isolated from H pluvialis through a I PCR and RACE (rapid ampliifcation of eDNA ends)method.And the completing eDNA encoded a protein which had high homology with the major component proteins of p1astog1obu1es in many plants and was termed as HPGP(Haematococcus plastoglobules protein).Furthermore,this cDNA was expressed in the prokaryotic expression system,and the resultant fusion proteins with His・Tags were puriifed by immobilized metal afinifty chromatography(IMAC).The polyclonal antibodies against the protein were raised in rabbits and the raw serum was collected without further purification.Those might provide an important basis for unraveling the function of the protein in the future. Key words:Haematococcus pluvialis;Astaxanthin;Plastoglobu1es;Gene cloning;Prokaryotic expression;Antibody