ISDTool: A computational model for predicting immunosuppressive domain of HERVs

Human endogenous retroviruses (HERVs) have been found to act as etiological cofactors in several chronic diseases, including cancer, autoimmunity and neurological dysfunction. Immunosuppressive domain (ISD) is a conserved region of transmembrane protein (TM) in envelope gene (env) of retroviruses. In vitro and vivo, evidence has shown that retroviral TM is highly immunosuppressive and a synthetic peptide (CKS-17) that shows homology to ISD inhibits immune function. ISD is probably a potential pathogenic element in HERVs. However, only less than one hundred ISDs of HERVs have been annotated by researchers so far, and universal software for domain prediction could not achieve sufficient accuracy for specific ISD. In this paper, a computational model is proposed to identify ISD in HERVs based on genome sequences only. It has a classification accuracy of 97.9% using Jack-knife test. 117 HERVs families were scanned with the model, 1002 new putative ISDs have been predicted and annotated in the human chromosomes. This model is also applicable to search for ISDs in human T-lymphotropic virus (HTLV), simian T-lymphotropic virus (STLV) and murine leukemia virus (MLV) because of the evolutionary relationship between endogenous and exogenous retroviruses. Furthermore, software named ISDTool has been developed to facilitate the application of the model. Datasets and the software involved in the paper are all available at https://sourceforge.net/projects/isdtool/files/ISDTool-1.0.     

含有CPP32基因的逆转录病毒载体的构建

含有ＣＰＰ３２基因的逆转录病毒载体的构建姚潇１叶棋浓２王恒梁２袁仕取１刘全宏１苏国富２（１陕西师范大学生命科学学院，西安７１００６２；２军事医学科学学院生物工程研究所，北京１０００７１；第一作者，男，３０岁，助教）ＣＰＰ３２（ＣｙｓｔｅｉｎｅＰｒｏｔ...     

血友病B基因治疗进展

血友病B是一种严重的凝血功能缺陷遗传病，由于现行的治疗方法对血友病B的治疗效果均不令人满意。因此，有必要开展血友病的基因治疗研究。本文介绍了血友病B的发病机理以及以反转录病毒载体为工具进行血友病B基因治疗的研究进展。     

病毒学对分子生物学发展的贡献

本文通过回顾病毒学发展史上的重大事件，尝试从以下几个方面说明病毒学的新发现对分子生物学发展所做出的贡献：①噬菌体感染实验和植物病毒重建实验证明了核酸是遗传信息的载体；②逆转录病毒的发现使人们认识到遗传信息的流动不是单向的；③逆转录酶已经成为基因克隆中重要的工具酶；④朊病毒的发现使人们认识到蛋白质很有可能成为核酸之外遗传信息的载体，扩展了人们对中心法则的认识；⑤各种野生型病毒被改造成为基因工程载体，广泛应用于基因工程．     

Specific targeted killing of ErbB2 positive breast cancer by retro virus-mediated Immunocaspase-3 secreting T cells

In this study, lmmunocaspase-3 gene was transfected into Jurkat T lymphocytes and the targeted proapoptotic protein Immunocaspase-3 was stably secreted.Its entry to ErbB2 positive SKBr3 breast carcinoma cell line was observed by indirect immunofluorescence staining.Growth of SKBr3 cells was significantly inhibited when they were cultured with medium containing Immunocaspase-3.Next, lmmunocaspase-3 gene was cloned into retrovirus vector pLNCX, which was then transfected into PA317 cells to package. Packaged cells producing high titer pseudoviruses were acquired and the pseudoviruses were harvested to infect PBMCs, which had been stimulated to division. The latter were selected and administered to nude mice bearing SKBr3 tumors through tail vein. The results showed that the treatment contributed to an inhibition of tumor growth and prolonged the lifetime of nude mice bearing SKBr3 tumor.The efficiency of inhibition of tumor reached 73.25%, and the average lifetime of treated nude mice was 80.95% longerthan that of control group. Immunohistochemical examination revealed the exclusive distribution of Immunocaspase-3 proteins only in the tumor tissue samples; and TUNEL assay confirmed the occurrence of apoptosis in tumor calls. Thepresent study suggests that Immunocaspase-3 secreted by T lymphocytes can selectively bind and enter into ErbB2 positive breast cancer cells, where it exhibits a proapoptotic activity and causes tumor suppression in an in vivo tumor model.     

单嗜性包装细胞包装逆转录病毒方法研究

逆转录病毒的感染范围(嗜性)是由所使用的包装细胞表达的包膜蛋白所决定的,因此改变现有的包装细胞的包膜蛋白就可以改变所包装的逆转录病毒的嗜性。为了达此目的,在稳定表达MMLV包膜蛋白的逆转录病毒包装细胞BOSC23细胞中共转染VSV-G表达载体和表达GFP的逆转录病毒载体,结果包装出的逆转录病毒只能感染少量的人源性的293F细胞,说明VSV-G不能完全替换掉MMLV包膜蛋白。因此我们利用RNA干扰技术首先沉默BOSC23细胞中的MMLV包膜蛋白的表达,然后共转染VSV-G表达载体和表达GFP的逆转录病毒载体,结果包装出了高滴度的泛嗜性的逆转录病毒。     

携带TIMP-1基因逆转录病毒载体的构建及其实验研究

构建携带组织金属蛋白酶抑制物ＴＩＭＰ－１基因的逆转录病毒载体，并用于感染胰腺癌ＳＷ１９９０细胞系，观察其侵袭、转移能力的变化．利用常规分子克隆技术，通过对逆转录病毒表达载体ＰＭＮＳＭ（Ｆ６）质粒的去磷酸化、粘端连接，构建ＴＩＭＰ－１基因逆转录病毒表达载体ＰＭＮＳＭ／ｈＴＩＭＰ；经限制性内切酶酶切、电泳鉴定其结构正确后，用电穿孔法对体外培养的ＰＡ１３７包装细胞进行基因转移，Ｇ４１８筛选阳性克隆，收集上清，并用于感染胰腺癌ＳＷ１９９０细胞系的研究．构建获得ＴＩＭＰ－１基因逆转录病毒表达载体ＰＭＮＳＭ／ｈＴＩＭＰ，有效滴度为１０４ＣＦＵ／ｍＬ～１０６ＣＦＵ／ｍＬ．本研究构建获得的ＴＩＭＰ－１基因逆转录病毒表达载体，在感染胰腺癌ＳＷ１９９０细胞系，观察其侵袭、转移能力的研究中得到有效应用     

病毒载体滴度对基因转移效率的影响研究

用改良的经典方法测定包装ＬａｃＺ基因的腺病毒和逆转录病毒载体的病毒滴度，以及用新建的简便方法测定逆转录病毒载体的病毒滴度．应用此两种病毒载体介导ＬａｃＺ基因分别导入１５种人或小鼠靶细胞，并以不同滴度的病毒上清液转染靶细胞Ｋ５６２，探讨病毒滴度对基因转移效率的影响．实验结果表明，病毒滴度与转染效率呈正相关，逆转录病毒滴度由１０６ＣＦＵ／ｍＬ降至１０４ＣＦＵ／ｍＬ时，用其转染Ｋ５６２细胞的转染效率由９０％降至２０％；ＣＡ启动子腺病毒滴度由０．４×１０９ＣＦＵ／ｍＬ降至０．２×１０７ＣＦＵ／ｍＬ时，对Ｋ５６２细胞的转染率由１００％降至３５％．同时表明，腺病毒滴度高，其转染率亦远比逆转录病毒高