人纤溶酶原激活剂抑制物2型(PAI-2)在Pichia pastoris中的表达

用ＰＣＲ方法从ｐＰＡＩＪ．７中扩增人纤溶酶原激活剂抑制物２型（ＰＡＩ－２）基因,与ｐＰＵＣ１８重组,经限制性内切酶片段分析与核苷酸序列分析,获得全长人ＰＡＩ－２基因．ＰＡＩ－２基因与表达载体ｐＰＩＣ９重组,构建受乙醇氧化酶１基因（ＡＯＸ１）启动子与转录终止区控制的酵母表达质粒,转化ＧＳ１１５宿主菌,经表型筛选和ＰＣＲ扩增筛选阳性克隆,用甲醇诱导表达,重组ＰＡＩ－２以分泌型表达,占分泌总蛋白的３０％,具ＰＡＩ－２抗原性,与低分子量尿激酶形成了抗ＳＤＳ复合物,具抑制纤溶的活性（９１．４ＡＩＵ／ｍｌ）．对培养条件也进行了探讨．     

含人IL－2基因的真核表达质粒的构建及其在真核细胞中的表达

本工作用ＰＣＲ由人的外周血单个核细胞。ｃＤＮＡ人中获取了带有信号肽的ＩＬ－２全ｃＤＮＡ克隆,并构建了不同的表达质粒：带有ＳＶ４０启动子的以质粒为载体的ｐＳＶＫ３－ＩＬ２和以逆转录病毒为载体的ｐＬＮ－ＩＬ２系列：ｐＬＮＣＩＬ２,ｐＬＮＳＩＬ２,ｐＬＩＬ２ＳＮ,它们分别带有ＣＭＶ、ＳＶ４０和ＬＴＲ启动子。用ＤＥＡＥ－Ｄｅｘｔｒａｎ法、ＳＡ→脂质体法和电穿孔等方法分别将这些ＩＬ－２表达质粒转染人ＣＯＳ－７及ＣＴＬＬ－２细胞中,测定不同时间细胞培养液上清中ＩＬ－２的量。结果表明,这些表达质粒在靶细胞中均有不同程度的一过性表达,ＩＬ－２的分泌至少可持续５天,转染后７２～９６小时ＩＬ－２产量最高,一般可达２８～３０Ｕ／ｍｌ,最高为５０Ｕ／ｍｌ。本工作比较了不同启动子和表达调控元件对ＩＬ－２表达的影响,还比较了在不同靶细胞中这些表达质粒产生ＩＬ－２的量。     

乙型肝炎、肝硬变和肝癌中HBxAg的表达及其在肝癌发生中的作用

对３７９例良、恶性肝组织进行的免疫组织化学研究显示,３３％的慢性迁延性肝炎（６／１８）、７６％的慢性活动性肝炎（２６／３４）、９２％的肝硬变（５７／６２）和９７％的肝细胞性肝癌（ＨＣＣ）（５８／６０）中有ＨＢｘＡｇ表达,阳性率高于ＨＢｓＡｇ或ＨＢｃＡｇ。癌周肝中的ＨＢｘＡｇ阳性率显著高于非癌周肝。与其它２种ＨＢＶ抗原不同,ＨＢｘＡｇ表达在细胞类型上有较明显的选择性,在肝小多角细胞（ＳＰＬＣ）、小细胞性不典型增生（ＳＣＤ）及ＨＣＣ中较强。与ＩＧＦⅡ、ｃ－ｅｒｂＢ－２、ｃ－ｍｙｃ和ＥＧＦ－Ｒ表达进行的对照研究表明ＨＢｘＡｇ与ＩＧＦⅡ和ｃ－ｅｒｂＢ－２这２种ＨＣＣ发生相关基因的表达关系密切。ＰＣＮＡ染色结果显示ＨＢｘＡｇ阳性组织的细胞增殖活性显著高于ＨＢｘＡｇ阴性组织。我们的结果还表明ＨＢｘＡｇ表达与肝细胞不典型增生的发生和进展有关、提出ＨＢＶＸ基因可能通过其表达产物（ＨＢｘＡｇ）首先激活ＩＧＦⅡ、ｃ－ｅｒｂＢ－２基因,继而引起显著的ＳＰＬＣ增生和ＳＣＤ而参与ＨＣＣ发生的．     

Bcl——2基因表达对TNF及OA诱发的细胞编程死亡的不同效应

用ＴＮＦ和ＯＡ（Ｏｋａｄａｉｃａｃｉｄ）诱发人神经母细胞瘤ＳＫ细胞死亡,并证明细胞死亡为编程死亡（ＰｒｏｇｒｍｍｅｄＣｅｌｌＤｅａｔｈ,简称ＰＣＤ）。将编码Ｂｃｌ－２全长蛋白的ｃＤＮＡ植入ＰＪＸ４１ｎｅｏ载体中,使其表达由ＨＣＭＶ病毒起动子控制。形成的顺义（ｐＢｃｌ－２－Ｓ）及反义（ｐＢｃｌ－２－ＡＳ）表达质粒经转染导入ＳＫ细胞中获得稳定转染子。Ｗｅｓｔｅｒｎ印迹表明顺义转染子表达大量的２６ｋｄＢｃｌ－２蛋白,而反义转染子则不表达。增强表达的Ｂｃｌ－２蛋白能抑制由ＴＮＦ引发的ＰＣＤ,但不影响ＯＡ引发的ＰＣＤ,从而证明了Ｂｃｌ－２基因产物抗细胞死亡效应的特异性。     

木糖代谢基因表达水平对酿酒酵母重组菌株产物形成的影响

以Ｅ．ｃｏｌｉ－Ｓ．ｃｅｒｅｖｉｓｉａｅ穿梭质粒ＹＥｐ２４为骨架,将树干毕赤酵母（Ｐｉｃｈｉａ ｓｔｉｐｉｔｉｓ ＣＢＳ６０５４）的木糖还原酶（ＸＲ）基因ＸＹＬ１及木糖醇脱氢酶（ＸＤＨ）基因ＸＹＬ１分别以不同的相对表达方向置于酿酒酵母的乙醇脱氢酶Ｉ（ＡＤＨ１）启动子和磷酸甘油激酶（ＰＧＫ）启动子下,构建不同ＸＹＬ１及ＸＹＬ２的重组质粒。这些重组质粒分别转化酿酒酵母（Ｈ１５８）受体菌。得到的重组菌株     

可溶性55kD人肿瘤坏死因子受体(shTNFR55)在变铅青链霉菌中的分泌表达

从 Ｈｅ Ｌａ 细胞中提取总 Ｒ Ｎ Ａ,采用反转录 Ｐ Ｃ Ｒ 技术,从该总 Ｒ Ｎ Ａ 中扩增了约 ５３０ ｂｐ 的ｓｈ Ｔ Ｎ Ｆ Ｒ５５ 基因的 ｃ Ｄ Ｎ Ａ,并克隆至质粒 ｐ Ｕ Ｃ ｍ ｅｌ中酪蛋白酶 ｍ ｅｌ Ｃｌ 分泌信号肽编码序列的下游,构建成含融合基因 ｍ ｅｌ／ Ｔ Ｎ Ｆ Ｒ 的重组质粒 ｐ Ｕ Ｃ ｍ ｅｌ／ Ｔ Ｎ Ｆ Ｒ．把融合基因 ｍ ｅｌ／ Ｔ Ｎ Ｆ Ｒ 插入链霉菌表达质粒 ｐ Ｉ Ｊ４５９ 的多克隆位点,使之位于 ｅｒｍ 强启动子的下游,得到重组表达质粒 ｐ Ｉ Ｊ４５９ ｍ ｅｌ／ｓ Ｔ Ｎ Ｆ Ｒ．经 Ｓｏｕｔｈｅｒｎ 杂交证明重组质粒 ｐ Ｉ Ｊ４５９ ｍ ｅｌ／ｓ Ｔ Ｎ Ｆ Ｒ 插入了 ｓ Ｔ Ｎ Ｆ Ｒ５５ 基因片段．对重组菌株 Ｓｔｒｅｐｔｏｍ ｙｃｅｓ ｌｉｖｉｄａｎｓ（ｐ Ｉ Ｊ４５９ ｍ ｅｌ／ｓ Ｔ Ｎ Ｆ Ｒ）的发酵液进行 Ｓ Ｄ Ｓ Ｐ Ａ Ｇ Ｅ、受体配基杂交（ Ｌｉｇａｎｄ ｂｌｏｔ）分析、对 Ｔ Ｎ Ｆ 敏感的 Ｌ９２９ 细胞的细胞毒性中和试验表明,可溶性肿瘤坏死因子受体 ｓ Ｔ Ｎ Ｆ Ｒ５５ 在链霉菌中得到了分泌表达,表达产物具有生物学活性．表达产物的分子量约在 ２６～２８ ｋ Ｄ 之间．     

超临界CO2萃取珊瑚姜根茎的化学成分

超临界ＣＯ２萃取珊瑚姜根茎的化学成分袁果先静缄袁家谟巫华美（贵州省生物研究所,贵阳５５０００９）ＴＨＥＣＨＥＭＩＣＡＬＣＯＮＳＴＩＴＵＥＮＴＳＯＦＺＩＮＧＩＢＥＲＣＯＲＡＬＬＩＮＵＭＢＹＳＵＰＥＲＣＲＩＴＩＣＡＬＣＡＲＢＯＮＤＩＯＸＩＤＥＥＸＴＲＡ...     

含人IL—2基因的真核表达质粒的构建及其在真核细胞…

本工作用ＰＣＲ由人的外周血单个核细胞ｃＤＮＡ中获取了带有信号肽的ＩＬ－２全ｃＤＮＡ克隆,并构建了不同的表达质粒：带有ＳＶ４０启动子的以质粒为载体的ｐＳＶＫ３－ＩＬ２和以逆转录病毒为载体的ｐＬＮ－ＩＬ２系列?ｐＬＮＣＩＬ２,ｐＬＮＳＩＬ２,ｐＬＩＬ２ＳＮ,它们分别带有ＣＭＶ、ＳＶ４０和ＬＴＲ启动子。用ＤＥＡＥ－Ｄｅｘｔｒａｎ法、ＳＡ－脂质体法和电穿孔等方法分别将这些ＩＬ－２表达质粒转染入ＣＯＳ－７及     

同时表达多种外源基因的非复制型重组痘苗病毒的构建

利用非复制型痘苗病毒载体,构建了能同时表达乙型肝炎（乙肝）病毒ＳＳ１、麻疹病毒ＨＡ和Ｆ及白细胞介素２（ＩＬ－２）的非复制型重组痘苗病毒ＶＩＨＩＬ２△ＣＫＳＳ１,及其相应的复制型重组豇轩病毒ＶＨＦＩＬ２ＳＳ１。这两株重组病毒在ＣＥＦ细胞上连续传至第２５代,经Ｓｏｕｔｈｅｒｎ,两株病毒均在Ａ２４、Ａ２７间稳定整合有ＳＳ１基因,非复制型重组病毒Ｃ、Ｋ间基因稳定缺失。经ＲＩＡ、ＥＬＩＳＡ及Ｗｅｓｔｅｒｎ     

庚型肝炎病毒包膜糖蛋白E2基因在昆虫细胞中的表达

用ＰＣＲ扩增出ＨＧＶＥ２全基因,克隆进杆状病毒表达载体ｐＦＡＳＴＢＡＣＨＴａ中,构建成重组转座载体ｐＦＡＳＴＢＡＣＥ２,转化ＤＨ１０ＢＡＣ大肠杆菌感受态细胞,筛选阳性菌落,抽提大分子质粒ＤＮＡ,获得含ＨＧＶＥ２基因的重组杆状病毒穿梭载体,转染昆虫草地夜蛾Ｓｆ９细胞,出现细胞病变后,收集含有重组病毒颗粒的培养上清,重新感染草地夜蛾Ｓｆ９单层细胞及甜菜夜蛾幼虫,分别收集Ｓｆ９细胞和甜菜夜蛾幼虫体内的血淋巴细胞,进行１２％ＳＤＳ聚丙烯酰胺凝胶电泳,可见表达的融合蛋白带,经亲和层析进行蛋白纯化,用ＥＬＩＳＡ方法检测各类血清标本,初步研究ＨＧＶＥ２糖蛋白的抗原性     

酵母SUC2基因上游顺序对其表达的影响

从SUC2基因上游约—900bp向起始密码进行系列缺失。将带有这种缺失上游区的SUC2基因插入多拷贝质粒,并转化进不产蔗糖酶的酵母细胞。测定了这些缺失株表达蔗糖酶的数量。结果表明:在葡萄糖阻遏条件下,SUC2上游区缺失从-636bp到-179bp的不同细胞,糖基化蔗糖酶的表达量逐渐升高。和野生型相比,SUC2上游区缺失到-223bp和-179bp的细胞糖基化蔗糖酶量增加100倍以上。在葡萄糖去阻遏条件下,SUC2上游缺失从-395bp到-179bp的不同细胞,糖基化蔗糖酶的表达量只显示微弱的去阻遏效应。缺失末端达-89bp和-41bp的细胞只表达很少的糖基化蔗糖酶,但是非糖基化蔗糖酶的表达量明显增加。     

Localization of cloned invertase in Saccharomyces cerevisiae directed by the SUC2 and MFalpha1 signal sequences

Protein localization in Saccharomyces cerevisiae was studied with two plasmid systems used as a model: one containing the SUC2 structural gene fused with the MFalpha1 (alpha-factor) promoter and signal-sequence, the other containing the entire SUC2 gene. Special emphasis was placed on the effect of promoter/signal-sequence (SUC2 vs. MFalpha1) on the efficiency of invertase transport. The MFalpha 1 and SUC2 signal sequences were capable of transporting, respectively, 83% and 77% of cloned invertase out of the cytoplasm. However, the SUC2 promoter was easier to control since a six-fold enhancement of the transported invertase activity associated with derepression was achieved in response to a glucose concentration change from 10 to 2 g/L Cloning on a multicopy plasmid resulted in a four-fold increase in total specific invertase activity over the wild type yeast strain (which harbors a single copy of the SUC2 gene on the chromosome), whereas the chromosomal site was more efficient for invertase localization yielding over 90% of the invertase transported out of the cytoplasm. Transient experiments done with the SUC2 signal-sequence-containing plasmid showed that the specific invertase activity in the periplasmic space reached a maximum three hours after derepression, then decreased very slowly with an accompanying gradual increase in invertase activity in the growth medium.     

Short repeated elements in the upstream regulatory region of the SUC2 gene of Saccharomyces cerevisiae.

Expression of secreted invertase from the SUC2 gene is regulated by carbon catabolite repression. Previously, an upstream regulatory region that is required for derepression of secreted invertase was identified and shown to confer glucose-repressible expression to the heterologous promoter of a LEU2-lacZ fusion. In this paper we show that tandem copies of a 32-base pair (bp) sequence from the upstream regulatory region activate expression of the same LEU2-lacZ fusion. The level of expression increased with the number of copies of the element, but was independent of their orientation; the expression from constructions containing four copies of the sequence was only twofold lower than that when the entire SUC2 upstream regulatory region was present. This activation was not significantly glucose repressible. The 32-bp sequence includes a 7-bp motif with the consensus sequence (A/C)(A/G)GAAAT that is repeated at five sites within the upstream regulatory region. Genetic evidence supporting the functional significance of this repeated motif was obtained by pseudoreversion of a SUC2 deletion mutant lacking part of the upstream region, including two copies of the 7-bp element. In three of five pseudorevertants, the mutations that restored high-level SUC2 expression altered one of the remaining copies of the 7-bp element.     

Genes Affecting the Regulation of SUC2 Gene Expression by Glucose Repression in SACCHAROMYCES CEREVISIAE

Mutants of Saccharomyces cerevisiae with defects in sucrose or raffinose fermentation were isolated. In addition to mutations in the SUC2 structural gene for invertase, we recovered 18 recessive mutations that affected the regulation of invertase synthesis by glucose repression. These mutations included five new snf1 (sucrose nonfermenting) alleles and also defined five new complementation groups, designated snf2, snf3, snf4, snf5, and snf6. The snf2, snf4, and snf5 mutants produced little or no secreted invertase under derepressing conditions and were pleiotropically defective in galactose and glycerol utilization, which are both regulated by glucose repression. The snf6 mutant produced low levels of secreted invertase under derepressing conditions, and no pleiotropy was detected. The snf3 mutants derepressed secreted invertase to 10-35% the wild-type level but grew less well on sucrose than expected from their invertase activity; in addition, snf3 mutants synthesized some invertase under glucose-repressing conditions.--We examined the interactions between the different snf mutations and ssn6, a mutation causing constitutive (glucose-insensitive) high-level invertase synthesis that was previously isolated as a suppressor of snf1. The ssn6 mutation completely suppressed the defects in derepression of invertase conferred by snf1, snf3, snf4 and snf6, and each double mutant showed the constitutivity for invertase typical of ssn6 single mutants. In contrast, snf2 ssn6 and snf5 ssn6 strains produced only moderate levels of invertase under derepressing conditions and very low levels under repressing conditions. These findings suggest roles for the SNF1 through SNF6 and SSN6 genes in the regulation of SUC2 gene expression by glucose repression.     

Yeast SKO1 gene encodes a bZIP protein that binds to the CRE motif and acts as a repressor of transcription.

We have cloned a yeast gene, SKO1, which in high copy number suppresses lethal overexpression of cAMP-dependent protein kinase. SKO1 encodes a bZIP protein that binds to the CRE motif, TGACGTCA. We found that SKO1 also binds to a CRE-like site in SUC2, a yeast gene encoding invertase which is under positive control by cAMP. A disruption of the SKO1 gene causes a partial derepression of SUC2, indicating that SKO1 is a negative regulator of the SUC2 gene. SKO1 interacts positively with MIG1, a zinc finger protein that mediates glucose repression of SUC2. A kinetic analysis revealed a complex regulation of the SUC2 mRNA in response to glucose. First, MIG1 mediates a rapid and strong repression of SUC2, which is complete within 10 minutes. Second, a MIG1-independent process causes a further slow reduction in the mRNA. Third, in the absence of MIG1, there is also a rapid but transient glucose induction of the SUC2 mRNA. This induction is correlated with a transient loss of SKO1-dependent repression.