Russell R A, Critchley R, Vassaux G, McClure M O
Jefferiss Research Trust Laboratories, Wright-Fleming Institute, Imperial College School of Medicine at St Mary's Hospital, Norfolk Place, London W2 1PG, UK.
Gene Ther. 2002 Oct;9(19):1326-32. doi: 10.1038/sj.gt.3301795.
The presence of closed circular forms of the linear DNA genome of human foamy virus (HFV) has not been established. The ability of the HFV integrase (IN) to catalyse the integration of these circular forms (termed 2 long terminal repeat (LTR) circles) was investigated, with a view to producing a novel hybrid vector. To this end, a construct was made containing, in addition to the enhanced green fluorescent protein (eGFP) marker gene, the last 27 bp of the 3' U5 LTR region of HFV fused to the first 28 bp of the 5' U3 LTR, the latter representing a 2LTR circle. Marker gene expression following transfection of both 293 and 293T cells indicated that the level of integration was not significantly increased by the HFV IN. Moreover, correctly integrated provirus-like forms of the input plasmid could not be detected by PCR. Taken together, these results show that the HFV IN is not able to integrate a circular molecule containing an LTR junction and, hence, the technique is not exploitable as a tool to produce hybrid vectors for gene therapy.
人泡沫病毒（HFV）线性DNA基因组的闭合环状形式是否存在尚未确定。研究了HFV整合酶（IN）催化这些环状形式（称为2个长末端重复序列（LTR）环）整合的能力，以期产生一种新型杂交载体。为此，构建了一个载体，除了增强型绿色荧光蛋白（eGFP）标记基因外，还包含HFV 3' U5 LTR区域的最后27个碱基对与5' U3 LTR的前28个碱基对融合，后者代表一个2LTR环。转染293和293T细胞后标记基因的表达表明，HFV IN并未显著提高整合水平。此外，通过PCR无法检测到输入质粒正确整合的前病毒样形式。综上所述，这些结果表明HFV IN无法整合含有LTR连接的环状分子，因此，该技术不能用作生产用于基因治疗的杂交载体的工具。
