GC盒不是人胰岛素基因启动子中关键顺式作用元件

目的 鉴定人胰岛素基因启动子中的GC盒(-348～-338)是否是启动子中的关键顺式作用元件.方法 用PCR克隆人胰岛素基因启动子,构建由人胰岛素基因启动子驱动的分泌型碱性磷酸酶(SEAP)报告质粒,并对报告质粒中人胰岛素基因启动子中的GC盒进行删除和突变.将报告质粒转染到β细胞系βTC3中,测定细胞培养液上清中SEAP的活性强度,进而判定GC盒与人胰岛素基因启动子转录活性的关系.结果 删除和突变人胰岛素启动子中的GC盒不能显著改变胰岛素基因启动子在β细胞中的转录活性.结论 人胰岛素基因启动子中GC盒不是一个关键顺式作用元件.     

人大肠癌细胞PRL-3基因启动子Snail结合位点的初步研究

目的 确定转录因子Snail可与PRL-3基因启动子区结合.方法 应用生物信息学方法获得PRL-3基因启动子区域,并对其潜在的Snail结合位点进行预测,进一步应用Snail抗体染色质免疫共沉淀技术结合PCR技术检测PRL-3基因启动子序列,以确定转录因子Snail可与PRL-3基因启动子结合.结果 应用TRED在线分析系统确定PRL-3基因的启动子区域位于PRL-0基因上游-700 bp至299 bp之间,在该启动子区域存在多个转录因子如Snail、n-MYC、ARNT、E74A、NF-kappaB、NRF-2及AML-1等的结合位点;在启动子区域的-500 bp至-451 bp之间存在Snail结合的核心寡核苷酸序列CACCTG,在其他多个区域存在多个类似这一核心序列的DNA序列;应用染色质免疫沉淀技术结合PCR扩增的方法对人大肠癌细胞株SW480细胞进行分析,发现Snail可与人大肠癌细胞株SW480 PRL-3基因的启动子区域的DNA片断结合.结论 转录因子Snail可与人大肠癌细胞SW480 PRL-3基因启动子结合,参与PRL-3基因的调控.     

Sequential analysis of hepatitis B virus core promoter and precore regions in cancer survivor patients with chronic hepatitis B before,during and after interferon treatment

We analysed the hepatitis B virus (HBV) core-promoter (CP) and precore (PC) regions before, during and after interferon treatment in young Caucasian cancer survivors who had acquired HBV infection during chemotherapy for malignancies. Fourteen patients with chronic hepatitis B [hepatitis B e antigen (HBeAg) /HBV-DNA positive] received α-2a interferon (IFN), 5  M U/m² t.i.w. for 12 months. HBV CP and PC region sequences were analysed following polymerase chain reaction (PCR) amplification. Sera from responders were studied at: T₀ (before starting IFN), T₁ [at alanine aminotransferase (ALT) peak preceding HBeAg seroconversion], T₂ (at ALT normalization), T₃ (at end of IFN) and T₄ (at one year after IFN) and in nonresponders at time points T₀, T₃ and T₄. Amplified HBV-DNA was cloned and sequenced automatically. Six of 14 patients (43%) responded to IFN treatment. Five of the six (83%) responders displayed the double CP mutation A1762T/G1764A always in association with a T1753C change. None of the nonresponders showed these mutations at any time point. The G1896A change creating the PC stop codon mutation was never detected in any of the patients. In our cancer survivors, IFN-induced HBeAg/anti-HBe seroconversion appeared to correlate with CP mutations and was not influenced by previous chemotherapy. These mutations in addition to low HBV DNA levels and elevated ALT can be considered favourable factors of response to IFN-induced anti-HBe seroconversion.     

乙型肝炎病毒C基因启动子和前C基因变异与HBeAg含量和肝炎病情的临床研究

研究乙型肝炎病毒(HBV)C基因启动子(CP)和前C基因变异对HBeAg表达和病情的影响。通过DNA扩增、基因序列分析检测48例慢性乙肝和12例慢性重型乙肝患者血清的HBV CP和前C基因序列,及通过微粒子发光法定量检测血清中HBeAg的含量。(1)前C终止变异(nt1896G→A)在重型乙型肝炎病例中的发生率显著升高(66.7％);CP双变异(nt1762A→T和1764G→A)则在慢性乙型肝炎中度和重度的病例中的发生率显著升高(分别为52.6％和54.5％)。(2)双变异组和终止变异组的HBeAg含量均显著下降,P<0.01。但终止变异组HBeAg含量的下降较双变异组更为明显,P<0.05,且eAb阳性率也显著升高,P相似文献   

Epigenetic Inactivation of Tumor Suppressor Genes in Hematologic Malignancies

A number of genetic alterations are involved in the development of hematologic malignancies. These alterations include the activation of oncogenes by chromosomal translocation or gene amplification and the inactivation of tumor suppressor genes by gene deletion or mutations. Recently, epigenetic change has been proven to be another important means of inactivating tumor suppressor genes in tumor cells, and hypermethylation of promoter DNA is one of the most important mechanisms. In hematologic malignancies, many kinds of tumor suppressor genes and candidate suppressor genes are epigenetically inactivated. Inactivation of tumor suppressor genes usually occurs in a disease-specific manner and plays important roles in the development and progression of the disease. Some of these alterations have clinical effects on treatment results or the prognoses of the patients.     

原发性肝癌患者乙型肝炎病毒C基因启动子变异与HBV DNA关系的探讨

目的研究原发性肝癌患者乙型肝炎病毒C基因启动子变异(HBVBCP)与HBVDNA关系。方法(1)采用PCR微板核酸杂交结合ELISA检测显示技术,对患者血清进行检测HBVBCP区核苷酸(nt)1762碱基A→T和1764G→A联合突变。(2)采用PCR结合荧光探针检测技术,检测患者血清HBVDNA含量。结果(1)HBVBCP变异在原发性肝癌组的阳性率为70.0%(14/20),显著高于慢性肝病组的阳性率37.8%(59/156)(P=0.008)。(2)原发性肝癌组的血清HBVDNA含量(107.6414±1.3398拷贝/ml)明显高于慢性肝病组的HBVDNA含量(106.7672±1.7669拷贝/ml)(P=0.034)。结论HBVBCP变异与原发性肝癌关系密切,且血清HBVDNA复制水平在原发性肝癌的发生中可能也起到主要的作用。