Danko I, Williams P, Herweijer H, Zhang G, Latendresse J S, Bock I, Wolff J A
University of Wisconsin-Madison, Department of Pediatrics, Waisman Center, 53705, USA.
Hum Mol Genet. 1997 Sep;6(9):1435-43. doi: 10.1093/hmg/6.9.1435.
There is a time window at 2 weeks of age for achieving very high levels of foreign gene expression from the intramuscular injection of naked plasmid DNA in mice and rats. The highest expression, over 1 microg of luciferase protein/muscle, was obtained in Balb/C mice using constructs containing the CMV promoter, a chimeric intron and the luc+ luciferase gene. Approximately 50% of the myofibers were intensely blue following the intramuscular injection of a beta-galactosidase expression vector in 2 week old Balb/C mice. The effects of age, mouse strain and construct were multiplicative, resulting in >1000-fold greater luciferase and approximately 20-fold more beta-galactosidase-positive cells. These high levels of expression were unstable and were not observed in larger animals (dog, rhesus monkey). These results indicate that enormous levels of foreign gene expression can be obtained in muscle with naked DNA in vivo and will enable the temporary effects of gene function and expression in rodent muscle to be expeditiously studied.
在小鼠和大鼠中，通过肌肉注射裸质粒DNA实现非常高水平的外源基因表达存在一个2周龄的时间窗口。使用含有巨细胞病毒（CMV）启动子、嵌合内含子和荧光素酶（luc+）基因的构建体，在Balb/C小鼠中获得了最高表达，即超过1微克荧光素酶蛋白/肌肉。在2周龄的Balb/C小鼠中肌肉注射β-半乳糖苷酶表达载体后，约50%的肌纤维呈现强烈蓝色。年龄、小鼠品系和构建体的影响是相乘的，导致荧光素酶表达增加>1000倍，β-半乳糖苷酶阳性细胞增加约20倍。这些高水平的表达不稳定，在较大动物（狗、恒河猴）中未观察到。这些结果表明，在体内用裸DNA可在肌肉中获得极高水平的外源基因表达，这将有助于快速研究啮齿动物肌肉中基因功能和表达的临时效应。
