p75真核表达载体的构建及其在PC-3细胞中的表达

目的：构建人神经生长因子低亲和力受体p75真核表达质粒,并在前列腺癌细胞PC-3中表达。方法：运用RT-PCR技术从人脑胶质细胞瘤组织中分离扩增编码人p75完整基因,与pcDNA载体重组,并通过酶切和测序鉴定;用脂质体介导法将重组质粒转染到PC-3细胞中,经G418筛选后,用RT-PCR、间接免疫荧光化学和细胞免疫组织化学法在转录和翻译两个水平上检测表达产物。结果：酶切和测序证实所获得的重组质粒包含p75完整基因;在转染pcDNA3．1( )-p75的PG3细胞中检测到转录和翻译产物。结论：成功地构建了p75真核表达质粒并在PC-3细胞中表达,为深入研究p75在前列腺癌中的生物学功能奠定了基础。     

人β防御素-2与前列腺癌特异性膜抗原嵌合蛋白真核表达质粒构建及其诱导的小鼠特异性免疫应答

探索人β防御素2 (h BD- 2 )和前列腺特异性膜抗原(PSMA)共表达重组核酸疫苗针对前列腺癌的免疫治疗。研究以pc DNA3.1为载体,构建重组质粒pc DNA3.1/PSMA和pc DNA3.1/h BD- 2 - PSMA,通过RT- PCR和免疫组化检测其表达。免疫小鼠后,进行血清中抗体检测,CD4 、CD8 T淋巴细胞数目测定及CTL 特异性杀伤作用检测。结果显示构建的质粒转染COS- 7细胞后能表达目的基因,免疫小鼠后能在体内持久表达,可以诱导产生特异性抗体,能有效的刺激T细胞增生,诱导特异性CTL 反应。当以h BD- 2作为免疫佐剂时,CTL 活性更强。本研究成功的构建了含PSMA的表达质粒,免疫小鼠可以诱导出有效的体液和细胞免疫,为前列腺癌的免疫治疗奠定了一定的实验基础     

Multiple spatially specific enhancers are required to reconstruct the pattern of Hox-2.6 gene expression.

Murine Hox genes are organized into four clusters that share many features with the homeotic clusters of Drosophila. This evolutionary conservation and the clear relationships between the position of a gene within a cluster and its expression pattern have led to the suggestion that the structure of the cluster is essential for proper regulation. Using a Hox-2.6-lacZ reporter gene in transgenic mice we have shown that the overall expression pattern of the endogenous Hox-2.6 gene can be reconstructed when it is isolated from the complex. The transgene was expressed in the proper tissues, with the correct spatial distribution and temporal pattern. Furthermore, direct comparison by in situ hybridization revealed that the levels of transgene expression are similar to those of the endogenous gene. This has allowed us to define three elements that regulate particular aspects of the Hox-2.6 pattern, two of which act as spatially specific enhancers. One enhancer, region A, directed expression only in the neural tube, whereas the other, region C, specified the majority of the Hox-2.6 pattern. Both were also capable of imposing the correct boundaries of expression on heterologous promoters. The definition of such elements will allow the characterization of the trans-acting factors that mediate spatial regulation in the mammalian embryo.     

人巨细胞病毒临床分离株UL131A-128mRNA转录方式的研究

目的 研究人巨细胞病毒（ human cytomegalovirns,HCMV） UL131 A-128序列在临床低传代分离株中的转录方式.方法 用3＇RACE技术扩增HCMV不同临床株,不同时期的UL131A,UL128,UL130的mRNAs并测序分析;利用PCR技术在HCMV临床株cDNA文库中筛选分别含有UL13IA,UL130,UL128序列的阳性克隆,测序并分析结果.结果 成功在临床低传代分离株中得到UL13IA,UL128,UL130基因的转录结构,UL131A,UL130的转录方式和文献报道一致,UL131A含有两个外显子,UL130为此区域内唯一不含内含子的基因.而UL128基因的转录本呈现了两种转录方式,一种结构包含三个外显子,长度为519 bp;而另一种结构包含三个外显子和第一内含子结构,长度为642 bp,在不同病毒株的不同时期均显示了包含第一内含子结构转录本的含量明显高于仅有外显子结构的UL128转录本的含量.UL131A-128三个基因在病毒的即刻早期,早期,晚期均存在.3＇RACE得到结果与HCMV cDNA文库筛选得到的结果相一致.结论 UL131A,UL130和UL128基因的mRNA结构的起始位点不同,但他们在3’末端拥有共同的终止位点.HCMV临床株UL 131A-128基因转录方式的复杂结构可能在HCMV感染的不同时期具有重要作用.     

Complementary homeo protein gradients in developing limb buds

A new human homeo box-containing gene designated Hox-5.2 was cloned and mapped to human chromosome 2. This homeo box is related in sequence to Abdominal-B, a Drosophila homeotic gene that specifies identity of posterior segments. An antibody probe was made using a human Hox-5.2 fusion protein and was found to stain posterior regions of mouse, chicken, and Xenopus embryos. Unexpectedly, when the distribution of Hox-5.2 antigen was compared with that of X1Hbox 1 antigen, a non-overlapping and mutually exclusive pattern was detected (e.g., in developing limb buds, intestine, and somites). Regions expressing Hox-5.2 do not express X1Hbox 1 protein, and vice versa. Hox-5.2 antigen is detected strongly in developing fore- and hindlimb buds, where it forms a gradient of nuclear protein throughout most of the mesenchyme. This gradient is maximal in distal and posterior regions. Hox-5.2 expression is activated in Xenopus limb regeneration blastemas, as expected for any gene involved in pattern formation. As described previously, a gradient of X1Hbox 1 protein can be detected in the forelimb. The latter gradient has the opposite polarity to that of Hox-5.2. i.e., maximal in anterior and proximal mesoderm. These two opposing gradients (and possibly others) could be involved in determining positional values in developing limb buds.