Rizzo W B, Schulman J D, Mukherjee A B
J Gen Virol. 1983 Apr;64 (Pt 4):911-9. doi: 10.1099/0022-1317-64-4-911.
We have investigated the use of liposomes as carriers for the transfer of simian virus 40 (SV40) DNA into mammalian cells. The amount of DNA entrapped in liposomes was dependent on the input DNA concentration and lipid composition. DNA remained intact after liposome encapsulation and was resistant to deoxyribonuclease digestion. Combined transfer to and expression of liposome-entrapped SV40 DNA in monkey kidney cells was assayed by infectious plaque formation. Negatively-charged liposomes containing phosphatidylserine were more effective in DNA transfer and expression than neutral liposomes. The inclusion of carrier salmon sperm DNA inhibited liposome-entrapped SV40 DNA infectivity. Infectivity of liposome-entrapped DNA was directly related to both liposome DNA concentration and number of vesicles added. Liposome-entrapped SV40 minichromosome was 20-fold more infective than free minichromosome, but only 20% more infective than liposome-entrapped SV40 DNA. Thus, the presence of hyperacetylated histones on the DNA failed to enhance liposome-mediated DNA transfer appreciably. Incubation of cells with various modulators of endocytosis implicated the endocytotic pathway in the mechanism of liposome-mediated DNA transfer. These studies show that liposomes are suitable carriers for the introduction of viral DNA and chromatin into mammalian cells.
我们研究了脂质体作为载体将猿猴病毒40（SV40）DNA转移到哺乳动物细胞中的应用。包裹在脂质体中的DNA量取决于输入的DNA浓度和脂质组成。DNA在脂质体包裹后保持完整，并且对脱氧核糖核酸酶消化具有抗性。通过感染性噬斑形成来测定脂质体包裹的SV40 DNA在猴肾细胞中的联合转移和表达。含有磷脂酰丝氨酸的带负电荷的脂质体在DNA转移和表达方面比中性脂质体更有效。加入载体鲑鱼精DNA会抑制脂质体包裹的SV40 DNA的感染性。脂质体包裹的DNA的感染性与脂质体DNA浓度和添加的囊泡数量直接相关。脂质体包裹的SV40微型染色体的感染性比游离微型染色体高20倍，但仅比脂质体包裹的SV40 DNA高20%。因此，DNA上高度乙酰化组蛋白的存在未能明显增强脂质体介导的DNA转移。用各种内吞作用调节剂处理细胞表明内吞途径参与脂质体介导的DNA转移机制。这些研究表明脂质体是将病毒DNA和染色质引入哺乳动物细胞的合适载体。
