HBx基因真核表达载体的构建及表达

目的 构建重组HBx蛋白的真核表达载体pIRES2-AcGFP-HBx.方法 设计合成HBx基因的特异性PCR引物.PCR扩增获得HBx基因序列;将HBx基因序列克隆人T载体(pGEM-T-HBx);再用限制性内切酶BglⅡ和EcoR Ⅰ双酶切下目的片段,将其亚克隆人真核表达载体pIRES2-AcGFP;双酶切(Bgl Ⅱ和EcoR Ⅰ)和序列测定鉴定重组子;脂质体包裹pIRES2-AcGFP-HBx转染入HepG2细胞,G418筛选得到稳定表达HBx的细胞克隆,Western blot检测HBx蛋白在转染细胞中的表达情况.结果 PCR扩增获得全长HBx基因序列;双酶切筛选得到阳性重组子,测序分析证实插入序列正确;转染plRES2-AcGFP-HBx的HepG2细胞,荧光显微镜可观察到GFP的表达,Western blot 证实表达HBx蛋白.结论 成功构建重组HBx基因真核表达载体,获得稳定表达HBx蛋白的HepG2细胞株,为深入研究HBx蛋白的生物学功能提供实验条件.     

丙型肝炎病毒CTL表位基因真核表达载体的构建及稳定转染细胞系的建立

目的构建含丙型肝炎病毒（HCV）复合多表位基因的真核表达载体,转染CHO细胞,建立稳定转染细胞系。方法通过生物信息学预测分析的方法得到涵盖HCV不同基因型与小鼠H2复合体的多个细胞毒性T淋巴细胞（CTL）表位,串联后人工合成基因序列,将其克隆入真核表达载体pEGFP-N3中,然后利用脂质体法转染CHO细胞,通过持续G418筛选建立稳定转染细胞株。最后通过荧光显微镜观察、RT-PCR和Western Blot等方法证实多表位基因的表达。结果所构建的含有HCV复合多表位基因的真核表达载体pEGFP-mEpi在CHO细胞中能稳定表达。结论真核表达载体的成功构建和稳定转染CHO细胞系的建立为进一步研究复合多表位疫苗的基因免疫奠定了基础。     

结核分枝杆菌复苏因子D基因在真核细胞中的表达

目的构建结核分枝杆菌复苏因子D基因（RpfD）真核表达载体,为结核分枝杆菌复苏因子DNA疫苗的研究奠定基础。方法 PCR扩增复苏因子D基因片段,克隆至PcDNA3.1（-）载体中,重组质粒测序正确后,转染至CHO细胞中。通过G418筛选,RT-PCR检测克隆基因mRNA在真核细胞的表达,Westernblot检测目的蛋白的表达。结果构建了PcDNA-RpfD表达载体,RT-PCR证实构建的载体能在CHO细胞中表达RpfD基因mRNA,Western blot证实转染了载体的CHO能表达RpfD蛋白质。结论成功构建PcDNA-RpfD真核表达载体,转染细胞CHO能表达RpfD蛋白质。     

先天性长QT综合征HERG基因真核表达质粒的构建及体外表达

目的构建携带HERG目的基因的真核表达重组质粒pcDNA3-HERG,并观察HERG基因在心肌细胞中的表达情况。方法应用基因重组技术,将原核克隆载体pGEM-HERG中HERG基因亚克隆到真核表达载体pcDNA3,以酶切和聚合酶链反应(PCR)方法鉴定重组质粒pcDNA3-HERG的正确性;以Lipofectamine为介导将重组质粒与荧光真核表达载体pRK5-GFP共转染培养的乳兔心肌细胞,转染48h后荧光显微镜下观察计算转染效率并采用Western Blot和全细胞膜片钳技术检测HERG基因的表达情况。结果酶切和PCR结果均证实pcDNA3-HERG的正确性,以脂质体为介导,其转染心肌细胞的效率为(15.2±2.6)%;Western Blot和膜片钳技术检测到HERG蛋白和HERG通道电流的表达。结论成功构建HERG基因真核表达重组质粒pcDNA3-HERG,转染心肌细胞后可表达有功能的离子通道,为今后研究突变型HERG的功能提供了可行的技术平台。     

HBV A83点变异真核表达载体的构建及其在HepG2细胞中的表达

研究A83点突变的生物学意义。采用分子生物学方法，设计引入KpnⅠ和HindⅢ酶切位点的引物扩增乙型肝炎病毒（HBV）ayw亚型的PcP10标准株中的Pre-C/C片段（1814-2452），经KpnⅠ和HindⅢ双酶切后，在T4DNA连接酶的作用下连于EB病毒真核表达载体。利用定点突变技术对连接载体进行1896点的定点诱变，经错配PCR-RFLP和测序分析。确定突变的克隆，提取突变前后的质粒转染HepG2细胞。突变后在Pre-1C/C第28位氨基酸形成终止密码。HBVA83点突变真核表达载体的构建为体外研究该点突变对HBeAg表达的影响以及HBeAg阴性的乙型肝炎病毒感染的致病机理奠定基础。     

日本血吸虫酪氨酸羟化酶基因的克隆、真核表达及鉴定

目的扩增日本血吸虫的酪氨酸羟化酶（Schistosoma japonicum Tyrosine Hydroxylase,SjTH）编码基因,构建pcDNA3.1(+) SjTH真核表达载体,并检测其在COS 7细胞中的表达情况。方法以日本血吸虫成虫cDNA为模板,RACE PCR扩增SjTH编码基因,并与pGEM T连接进行亚克隆,双酶切后回收目的基因,并与真核表达载体pcDNA3.1(+)连接,PCR和双酶切初步鉴定后测序,纯化无内毒素重组质粒pcDNA3.1(+) SjTH,转染入COS 7细胞,G418筛选阳性克隆,RT PCR和Western blot鉴定重组SjTH蛋白的表达。结果RACE PCR 扩增出SjTH编码基因,大小约1 392bp,经双酶切鉴定、测序及Blast分析鉴定重组真核质粒构建成功。脂质体介导无内毒重组真核质粒pcDNA3.1(+) SjTH转染入COS 7细胞,G418筛选出阳性克隆,RT PCR证实阳性单克隆细胞带有SjTH编码基因,Western blot鉴定单克隆细胞表达重组SjTH蛋白,大小约54kD。结论真核表达载体pcDNA3.1(+) SjTH构建成功,G418筛选出阳性克隆,真核表达重组SjTH蛋白,为后续研究SjTH蛋白功能奠定基础。     

乙型脑炎病毒非结构4A蛋白编码基因重组子的构建及表达

目的构建流行性乙型脑炎病毒(JEV)非结构4A(NS4A)蛋白编码基因重组子并鉴定。方法以JEV SA14-14-2株Total RNA为模板,运用RT-PCR方法扩增JEV NS4A蛋白编码基因,克隆至pMD19-T Simple载体并测序。为便于分析JEV NS4A蛋白编码基因重组子在哺乳动物细胞中的表达,在JEV NS4A蛋白编码基因5’端附加FLAG序列,亚克隆至pcDNA3.1(+)载体中,构建重组子pJNS4A并作酶切及DNA测序分析;采用脂质体法将pJNS4A转染中华仓鼠卵巢(CHO)细胞,采用免疫荧光法检测转染的CHO细胞中JEV NS4A蛋白分布与表达。结果重组质粒pJNS4A经BamHⅠ/EcoRⅠ酶切释出的插入子在830bp左右,与JEV NS4A蛋白编码基因和FLAG基因序列之和(834bp)相一致。JEV NS4A蛋白编码基因重组质粒转染的CHO细胞可见绿色荧光标记,主要分布在胞膜。结论 pJNS4A构建成功,转染的CHO细胞可稳定表达JEV NS4A蛋白。     

人GOR基因重组体的构建及其在C_(os)—7细胞内的表达

目的构建能正确表达人GOR蛋白的真核重组体,制备人源性GOR蛋白。方法将人GOR基因片段亚克隆到真核表达载体PCDNA31（－）／Myc－HisA,B,C系统,PCR法和EC。RⅠ酶切筛选重组体,KpnⅠ酶切鉴定重组体方向,正向重组体用磷酸钙共沉淀法分别转染Cos－7细胞。用PCR法和ELISA法分析重组体是否转入Cos—7细胞并能正确编码人GOR蛋白。最后制备人GOR蛋白。结果所构建的人GOR基因重组体A、B、C分别转染Cos—7细胞后,都能在细胞内转录;但只有重组体A能正确表达人GOR蛋白。结论　本研究所构建的人GOR基因真核重组体能正确表达人GOR蛋白。     

人硫氧还蛋白基因真核表达载体的构建及其在COS-7细胞中的表达

目的 克隆人硫氧还蛋白(hTRX)cDNA序列,进行真核表达载体的构建.方法 应用RT-PCR技术,以胎肝组织细胞总RNA为模板,扩增出hTRX成熟蛋白的cDNA基因,并克隆至pUCm-T载体中,经PCR和测序鉴定正确后,再构建重组真核表达载体pcDNA3.0-hTRX,采用PCR、双酶切和基因测序鉴定;利用阳性脂质体Lipofectamine将其转入COS-7细胞(瞬时表达细胞),RT-PCR检测其表达情况.结果 将所得序列与GenBank(J04026)提供的序列比较,其酶活性中心(Trp-Cys-Gly-Pro-Cya)和基序与已知序列一致;PCR、酶切及测序鉴定表明真核表达载体构建正确;COS-7细胞中有hTRX的表达.结论 成功克隆编码hTRX成熟蛋白的cDNA基因,构建其真核表达载体pcDNA3.0-hTRX,并在COS-7细胞中得到了表达,为进一步探讨hTRX的生物活性和应用奠定了基础.     

Virological and clinical implication of core promoter C1752/V1753 and T1764/G1766 mutations in hepatitis B virus genotype D infection in Mongolia

Background and Aim: The aim of the present study was to reveal virological and clinical features of hepatitis B virus (HBV) genotype D infection. Methods: One hundred and twenty‐two Mongolian chronic liver disease (CLD) patients infected with HBV were subjected for serological HBV‐markers screening and HBV‐enzyme immunoassay (EIA) genotyping. Nucleotide sequences were analyzed for 48 HBV/D strains (23 isolated from hepatocellular carcinoma (HCC) and 25 from CLD patients). Results: Prevalence of hepatitis B e antigen (HBeAg) positivity was low (25.9%) in young patients (≤30 years old) indicating early HBeAg seroclearance in HBV/D carriers. The T1764/G1766 double mutation was the most common basal core promoter (BCP) mutation (29.2%) and was frequent in HBeAg‐negative patients (39.3%). Patients harboring T1764/G1766 mutants exhibited lower HBV‐DNA and HBV core antigen (HBcAg) levels than those with wild‐type BCP strains (P = 0.024, 0.049, respectively). C1752 and/or V (not T) 1753 mutation was significantly prevalent in HCC patients (HCC vs CLD; 52.2% vs 20%, P = 0.033). T1762/A1764 mutation was detected in 75.0% of HCC patients with high viral load (≥5 log copies/mL). Precore stop codon mutation A1896 was detected in (70.8%) of HBV/D‐infected patients. Conclusions: In Mongolians infected with HBV/D, C1752 and/or V1753 mutation was associated with HCC.     

HBV T1719G mutation reduced HBV replication through mutant Enh II and HBx protein in vitro

It was repeatedly reported that the hepatitis B virus (HBV) T1719G mutation was very common and related to progression and malignancy of liver disease. However, its effect on viral replication efficiency remains unclear. In this study, we aimed to evaluate the function and mechanisms of the T1719G mutation on viral replication capacity. Wild‐type and T1719G mutation‐bearing HBV1.2× plasmids were transfected into Huh7 and HepG2 cells, respectively, and HBV total RNA, 3.5 kb RNA and supernatant HBV DNA were assessed using real‐time PCR, hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) levels were measured by time‐resolved fluoroimmunoassay. In order to assess Enh II activity and the binding capacity of HNF3β to Enh II sequence, dual‐luciferase assay and Chromatin immunoprecipitation (ChIP)‐PCR were employed, respectively. Simultaneously, the HBx or HBx‐mut (T1719G) plasmid was co‐transfected to evaluate the effect of HBx on viral replication. Our results showed that the T1719G mutation impaired viral replication efficacy compared with the wild type both by reducing Enh II activity and binding capacity of HNF3β with Enh II. And such reduction caused by T1719G mutation could be rescued by HBx protein. Our results show that the T1719G mutation decreases HBV viral replication capacity possibly by mutant HBx protein and altered Enh II activity.     

APOBEC3F剪接亚型与全长APOBEC3F、APOBEC3G对乙肝病毒作用的比较

目的比较APOBEC3F剪接亚型3F79与完整APOBEC3F以及APOBEC3G对HepG2.2.15细胞中HBV DNA复制及HBsAg、HBeAg抗原分泌的影响。方法用PCR合成法扩增人APOBEC3F剪接亚型3F79,构建真核表达载体pEGFPC1-3F79和原核表达质粒pET28a-3F79,将pEGFPC1-3F79与含有全长APOBEC3F和APOBEC3G的质粒Pflag-APOBEC3F、PC-APOBEC3G-HA转染入HepG2.2.15中,检测转染后细胞上清中HBV DNA以及HBsAg和HBeAg的水平。结果构建的重组载体经酶切和PCR鉴定,表明3F79基因正确地插入。将pEGFPC1-3F79与Pflag-APOBEC3F、PC-APOBEC3G-HA转染HepG2.2.15细胞后,pEGFPC1-3F79对细胞中HBV的复制及HBsAg和HBeAg的分泌无明显的抑制作用(P0.05),而转染含有完整APOBEC3F和APOBEC3G质粒的HepG2.2.15细胞与对照组相比,HBsAg、HBeAg、HBV DNA含量明显下降,差异有统计学意义(P0.05)。结论 3F79不能像完整APOBEC3F和APOBEC3G一样抑制HepG2.2.15细胞中HBV DNA复制以及抗原的分泌。     

广西慢性乙型肝炎患者HBV核心基因启动子突变的研究

目的 了解HBV核心基因启动子突变与肝损害程度或HBeAg状态的关系。方法 用套式PCR扩增59例慢性乙型肝炎患者血清HBV核心基因启动子,阳性者用直接测序法检测。结果35例HBV DNA阳性,阳性率为59.3％。无正常序列标本,最常见的突变类型是nt1762、1764发生双突(A→T、G→A),占57.1％;其次为nt1799位点突变,由C→G,占54.4%,为无义突变;nt1752位点突变,由A→G,使该密码由异亮氨酸变为缬氨酸,占37.1％;nt1753T→C,占20.0%。T_(1762)A_(1764)突变株在HBeAg阳性、阴性患者组中的分布分别为31.3％、79.0％,两者差异有显著性,x~2 8.068 8,P<0.05。结论 HBV核心基因启动子突变在广两慢性乙型肝炎患者较常见,T_(1762)A_(1764)突变株与HBeAg阴性及慢性肝炎有关。     

Hepatitis B virus genotypes and G1896A precore mutation in 486 Spanish patients with acute and chronic HBV infection

This study aims to determine the prevalence of hepatitis B virus (HBV) genotypes (A-F) and their association with the G1896A precore mutation in 486 patients positive for HBV surface antigen. Genotypes were determined by RFLP and precore mutation by real-time PCR. Genotypes D (48.1%) and A (39.5%) were the most common, followed by F (4.1%) and B, C and E (<1%). The A to D ratio (A:D) was 1.4 in HBeAg+ chronic hepatitis B (CHB), 0.6 in HBeAg- CHB and 1.4 in HBeAg- inactive carriers. Distribution of these genotypes was different between HBeAg+ CHB and HBeAg- CHB (P = 0.02), and between HBeAg- CHB and HBeAg- inactive carriers (P = 0.009). Genotype A was the most prevalent in HBeAg+ CHB with elevated alanine aminotransferase (ALT) (68.6%) and genotype D in HBeAg+ CHB with fluctuating ALT (60.7%). There was a difference in genotype prevalence between chronic and acute infection (P = 0.03). The precore mutant correlated with high levels of HBV-DNA in genotype d HBeAg- CHB. Genotype D is not as highly prevalent in Spanish patients as would be expected in a Mediterranean area. The unequal prevalence of genotypes between acute and chronic infection suggests that genotype A is associated with a higher tendency to cause chronic infection.     

HBeAg阳性患者中乙型肝炎病毒基因型分布及YMDD变异位点分析

目的通过研究乙型肝炎患者HBV基因型的分布及YMDD变异位点的分布特点,了解两者之间的关系,探讨临床意义。方法选取在我院门诊和住院部就诊的HBeAg阳性并经拉米夫定治疗两年以上的慢性乙型肝炎患者137例,用实时荧光PCR方法检测HBV DNA分型情况,用LDR方法检测YMDD位点变异情况。结果 137例患者中21例未能检测出基因型,其中男性17例,女性4例;其余116例标本确定了感染病毒的基因型,包括男性94例,女性22例;其中A型2例(1.72%)、B型19例(16.38%)、C型91例(78.45%)、D型4例(3.45%);分型成功率为84.67%(116/137)。116例标本中有41例患者的感染病毒中检测到了YMDD变异位点,变异发生率为35.35%。其中B基因型中检出7例(36.84%);C基因型中检出33例(36.26%);D基因型中检出1例(25.0%);A基因型中未检测出变异位点。B、C基因型中变异位点的检出率高于D型,但各基因型之间差异无统计学意义(χ2=1.392,P>0.05)。在41例变异中,其中I突变占60.9%,V突变占31.7%,I/V共生突变占7.4%。结论兰州大学第一医院所在地区患者中HBV基因型主要以C型为主,其次是B型,也有少量D、A型存在;B、C基因型的YMDD位点发生突变的几率相近。突变几率与基因型无关。     

Single‐nucleotide substitution of Hepatitis B virus in intrauterine infection

The relationship between hepatitis B virus (HBV) gene polymorphism and intrauterine infection has not been completely illuminated. Six pairs of mother and infant from intrauterine infection group and six mothers from nonintrauterine infection group in the previous study were randomly selected and separately divided into group M (Mother group), group N (Neonate group) and group NM (Negative‐mother group) in this study. We found that age, gestational weeks, HBsAg titre, HBeAg titre and HBV DNA level of mothers from group M and group NM were not significantly different. Pre‐S1/S2 and S regions in HBV genome were amplified, inserted into pUC19 plasmid and sequenced. It was found that all clone sequences clustered into genotype C ( AY123041 ) through the Genotyping tool in NCBI and phylogenetic trees. Compared with AY123041 , there were 20 (11 plus 9) mutations significantly different in the three groups. Most of the mutations were synonymous in pre‐S1/S2/S region, while mutations of C2990T, T3205A, A167G, C407A, A667T and A680C resulted in amino acid substitution of A90V, S162T, T47A, P127T, L213F and I218L, respectively. In addition, most of the 20 mutations caused amino acid substitution in polymerase region for the tight structure of HBV genome. The occurrence and location of mutations indicated that mutation of C2990T only existing in group NM may serve as an index for nonintrauterine infection. In contrast, the incidence of intrauterine HBV infection from mothers with mutation of T3205A was lower. Then, mutations of G403A, T670G, A673G, A167G, C407A, A667T and A680C may be closely related to intrauterine HBV infection.     

孕妇中乙型肝炎病毒前C区和核心启动子区热点变异研究

目的研究乙型肝炎病毒（HBV）携带产妇体内HBV前C区和核心启动子（CP）区热点变异情况。方法82例无症状慢性HBV携带临产孕妇采用HBV核酸扩增荧光定量检测试剂盒抽提孕妇血清HBVDNA,血清HBsAg、HBeAg采用EIA法检测,半巢式PCR法扩增产妇HBV前C区、CP区核苷酸片段,ABI3730型DNA自动荧光测序仪对PCR产物直接测序。结果82例无症状HBV携带临产孕妇中HBsAg单阳性52例,HBsAg、HBeAg双阳性30例;单阳性孕妇中1896G→A变异的检出率为21．2％（11／52）,仅测到1例双阳性孕妇存在1896G→A变异,1899G→A变异仅发生在1例单阳性孕妇,且与1896G→A变异连锁出现。1762A→／1764G→A变异总是连锁出现,且仅发生于单阳性孕妇,单阳性孕妇中双变异的检出率为17．3％（9／52）。结论HBV前C区、CP区1896G→A及1762A→T／1764G→A热点变异在无症状HBV携带单阳性孕妇中有较高的检出率,HBV前C区和核心启动子区的热点变异可能与肝损伤的严重程度无关。     

青岛地区乙型肝炎病毒基本核心启动子区基因突变与乙型肝炎病毒所致原发性肝癌的相关性

目的通过分析山东省青岛地区HBV核心启动子基因序列的突变特征,探讨其与乙型肝炎相关原发性肝癌的相关性。方法收取慢性乙型肝炎患者和乙型肝炎相关原发性肝癌患者的血清标本各60例,然后从中提取HBV DNA,采用聚合酶链反应(PCR)扩增、纯化、克隆后测序,根据S基因区的编码序列确定患者的基因型和血清型;分别将HBV核心启动子区的各序列结果与GeneBank中的HBV标准株做对比,用DNAMAN软件对基因序列进行突变分析。采用SPSS17.0软件进行统计学分析。结果 120例标本,HBV株均为B或C基因型,以C基因型为主,其中,HBV组的C基因型所占比率为83.33%,HCC组为90.00%(χ2=0.65,P=0.42);血清型均为adw2或adrq+。HBV基因组核心启动子区常见的点突变为C1653T、T1753V、C1754T及A1762T/G1764A,发生率分别为42.73%、86.36%、71.82%、38.18%。与慢性乙型肝炎患者相比,肝癌患者中发生率比较高的突变位点为C1653T(78.85%,χ2=52.58,P<0.001)及A1762T/G1764A(73.08%,χ2=50.88,P<0.001)。结论山东青岛地区HBV基因组常见为B、C基因型,其中以C型为主;核心启动子区突变发生率高,其中,T1753V与HCC发生无关,C1653T、A1762T和G1764A位点无论单独或是联合突变均与HCC发生密切相关。     

Combinations of eight key mutations in the X/preC region and genomic activity of hepatitis B virus are associated with hepatocellular carcinoma

Accumulation of eight key mutations located in the X/preC regions of the hepatitis B virus (HBV) genome (G1613A, C1653T, T1753V, A1762T, G1764A, A1846T, G1896A and G1899A) is a risk marker for the development of hepatocellular carcinoma (HCC). In this study, we analysed the 8 key mutations in 442 serum samples collected from 310 non‐HCC and 132 HCC patients to identify the combinations linked to HCC. After the patients were stratified according to the age groups and mutation combinations, clinical parameters were compared between the HCC and the non‐HCC groups. Analyses were focused on patient ≥40 years of age infected by HBV genotype C with A1762T and G1764A mutations in the basal core promoter region (BCP double mutation). In patients with ≥6 mutations, the combination of [G1613A + C1653T + A1846T + G1896A] mutations was closely linked to HCC, whereas no specific single or double mutation combination was associated with HCC. In patients with ≤5 mutations, HBeAg and HBV DNA serum titres were lower in the HCC group than those in the non‐HCC group. Unlike the number of mutations, no specific combination correlated with advanced clinical stage in HCC. Of the BCP double mutation–based HBV mutant types, combinations of ≥6 mutations that include G1613A + C1653T + A1846T + G1896A, and combinations of ≤5 mutations with reduced HBeAg production, may be more specific indicators of HCC risk than only the number of mutations or any specific combination(s).