Interaction Between HMG Proteins (1+2) and the Negative Regulatory Region 1(NCR1) in the 5''''-flanking Sequence of the Human β-globin Gene

The pattern of high mobility group proteins 1 and 2 (HMG1,2) interaction with the 5'-flanking sequence of the human β-globin gene has been analyzed by scanning tunnelling microscopy (STM). A 200 bp negative regulatory region in the 5'-flanking sequence of the human β-globin gene can be folded by HMG proteins 1 and 2 into a circular structure (diameter 70±6) with a linear tail which seems to be a left-handed double helix structure.     

正交试验与响应面法优化微波提取地黄多糖工艺研究

为了获得微波提取地黄多糖的最佳条件,采用正交试验法和响应面法分别优化微波提取地黄多糖工艺,以地黄多糖得率为指标,采用微波提取地黄多糖,苯酚-硫酸法测定地黄多糖的含量,以微波提取时间、提取温度和料液比进行三因素分析,根据单因素试验结果设计正交试验和响应面试验,进一步优化微波提取地黄多糖工艺.微波提取地黄多糖工艺通过正交试...     

Binding of HMG Proteins to the 5''''_Flanking Sequence of Human β-Globin Gene

Our previous studies have identified that there are at least three regulatory regions (two negative regions and one positive region) in the 5'-flanking sequence of human β-globin gene (-610 to +1 bp). The binding of HMG proteins to both negative regulatory regions was examined by the gel mobility shift and DNase I protection assays.In gel mobility shift assay,we observed that HMG proteins 1 and 2 could bind to both negative regulatory regions (NCR1 and NCR2).Using the gel shift competition assay,we identified that the binding proteins between the two regions are different from each other.DNase I protection analysis shows that HMG proteins 1 and 2 only bind to one site (between-560 and-533 bp) in NCR1.However,two protected regions can be detected in NCR2, one between-272 and-252 bp relative to the cap site, the other between-306 and-329 bp.We also observed that HMG proteins 14 and 17 could not bind to both negative regions, so it seems that HMG proteins 1 and 2 may play an important role in the regulati     

人体β-珠蛋白基因5′-旁侧DNA序列内的负调控区域1(NCR1)与HMG蛋白质(1+2)的相互作用

利用分子生物学技术和扫描隧道显微镜方法首次观察到HMG蛋白质(1+2)和人体β-珠蛋白基因的5′-旁侧DNA序列内的一个负调控区域(NCR1)相互作用的构象,这类蛋白质能将线状的DNA片段(～200bp)折叠起来,形成一个环状结构(直径70±6A)和°一条似乎呈现左手螺旋(z-from)的线状DNA尾巴。     

HMG蛋白质与人体β-珠蛋白基因5旁侧DNA序列的结合

人体β-珠蛋白基因的5′-旁侧DNA片段(-610bp→+1bp)内的两个负调控区域与HMG蛋白质(High Mobility Group Proteins)结合状况已用近代分子生物学的技术(足印分析法(DNase Ⅰ protection Assay)和凝胶电泳阻抑分析法(Gel MobilityShift Assays)加以分析。用凝胶电泳阻抑分析方法证明了HMG蛋白质(1+2)与两个负调控区域有不同程度的结合,同时也观察到这两个负调控区域的结合蛋白是各异的。为了进一步检测HMG蛋白质(1+2)与DNA序列的精确结合位点,我们又采用了足印分析的方法,观察到在第一个负调控区内HMG蛋白质(1+2)有一个专一的结合位点(-560bp→-533bp)。在第二个负调控区内,则可以检测到有两个结合位点(-272bp→-252bp和-306bp→-329bp)。另外,我们还证实了HMG蛋白质(14+17)与这两个负调控区都不能结合。上述实验结果提示HMG蛋白质(1+2)在β-珠蛋白基因表达中起着积极的调控作用。     

人表皮生长因子受体cDNA在酵母(Saccharomyces cerevisiae)中表达

人表皮生长因子受体(human epidermal growth factor receptor,简称hEGFR)是一个170kD的穿膜糖蛋白。利用酵母诱导型Gall启动子,hEGFR cDNA被成功地在酵母细胞中表达,其转录产物(mRNA)大小约为3.5kb。免疫荧光显微实验显示该mRNA的翻译产物(hEGFRy)是位于酵母细胞质膜上,并且hEGFRy具有与EGF结合的功能。本文还进一步证明了酵母2μm质粒的2kb的片段的确具有转录终止的功能。     

测定痕量钴的超高灵敏催化光度法的建立及应用

钴是人体必需微量元素之一,是维生素B12及其它钴化合物的组成部分.钴是生命科学、医学分析中的重要测试项目,如人头发中的钴含量较高,通过检测其含量可以确定人体的健康状况,故人发中钴含量的测定[1]有重要医学价值.另外钴也是环境监测中重要指标,因此研究钴的高灵敏分析方法有重要意义.催化光度法因所需仪器简单、操作简便、灵敏度高而受到广泛重视,在钴的测定中已有报道[2～5].