Ginsburg Daniel S, Calos Michele P
Department of Genetics Stanford University School of Medicine Stanford, California 94305, USA.
Adv Genet. 2005;54:179-87. doi: 10.1016/S0065-2660(05)54008-2.
Need of a site-specific integrating vector in gene therapy has become pressing, as recent work has shown that many of the current integrating vectors used preferentially integrate in the vicinity of genes. A site-specific integrating vector would reduce the risk of insertional mutagenesis posed by randomly integrating vectors, and a non-viral vector would reduce the safety and immunogenicity problems associated with viral vectors. The phiC31 integrase is a protein from Streptomyces phage phiC31 that has been developed as a non-viral site-specific gene therapy vector. The phiC31 integrase catalyzes the integration of a plasmid containing attB into pseudo attP sites in mammalian genomes. It has been shown to function in tissue culture cells as well as in mice. Vectors based on the phiC31 integrase were able to treat tyrosinemia type I in a mouse model and two forms of epidermolysis bullosa in keratinocytes from patients, demonstrating its effectiveness as a gene therapy vector. Development of phiC31 integrase-based vectors is still underway, but it has already been shown to provide long-term expression through site-specific integration.
随着近期研究表明，许多当前使用的整合载体倾向于优先整合在基因附近，在基因治疗中对位点特异性整合载体的需求变得紧迫。位点特异性整合载体将降低随机整合载体带来的插入诱变风险，而非病毒载体将减少与病毒载体相关的安全性和免疫原性问题。phiC31整合酶是一种来自链霉菌噬菌体phiC31的蛋白质，已被开发为一种非病毒位点特异性基因治疗载体。phiC31整合酶催化含有attB的质粒整合到哺乳动物基因组中的假attP位点。已证明它在组织培养细胞以及小鼠中发挥作用。基于phiC31整合酶的载体能够在小鼠模型中治疗I型酪氨酸血症，并在患者的角质形成细胞中治疗两种大疱性表皮松解症，证明了其作为基因治疗载体的有效性。基于phiC31整合酶的载体的开发仍在进行中，但已经表明它能够通过位点特异性整合提供长期表达。
