Inhibition of cleavage of Moloney murine leukemia virus gag and env coded precursor polyproteins by cerulenin.
Inhibition of cleavage of Moloney murine leukemia virus gag and env coded precursor polyproteins by cerulenin.
复制标题
浅蓝菌素抑制莫洛尼鼠白血病病毒 gag 和 env 编码的前体多蛋白的裂解。
DOI：
10.1016/0042-6822(86)90441-1
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发表时间：
1986
期刊：
影响因子：
3.7
通讯作者：
Luftig,RB
中科院分区：
文献类型：
--
作者：
Ikuta,K;Luftig,RB
浅蓝菌素是一种新生脂肪酸（和胆固醇）生物合成的抑制剂，已显示可显著降低（>75%）释放到慢性感染小鼠成纤维细胞培养基中的莫洛尼鼠白血病病毒（M-MuLV）的量（I. Katoh，Y. Yoshinaka和R. B。Luftig，1986年，病毒研究，印刷中）。为了阐明这种病毒产量减少的机制，我们用p30、p12、p10、gp 70和p15（E）的单特异性抗血清进行免疫沉淀，分析了经浅蓝菌素处理的M-MuLV感染细胞中gagandenvcoded蛋白合成的动力学。我们发现，在脉冲（15分钟-2小时）-追踪（0-4小时）实验中，浅蓝菌素处理不仅大大降低了Pr 65 gag到p30和其他gag编码蛋白的切割，而且也大大降低了Pr 80 env到gp 70和Pr 15（E）的切割。此外，由于Pr 65 gag和Pr 80 env带中标记的总量在2小时脉冲的浅蓝菌素处理的细胞中保持大致相同或略微降低，这表明浅蓝菌素部分地通过抑制病毒组装和在细胞膜上出芽期间两种经Pr 65 gag和Pr 80 env编码的多聚蛋白的切割来降低病毒产生。浅蓝菌素的作用可以部分地被抵消，因为产生了少量的裂解的、未编码的多聚蛋白并组装成病毒粒子。上述结果提示浅蓝菌素阻断M-MuLV产生的两种独立但不唯一的可能机制，即（i）浅蓝菌素减少脂肪酸库，从而抑制Pr 65 gag以及Pr 80 env的脂肪酸酰化，并因此阻止了在细胞膜上的ag（Pr 65 gag上的p15抗原决定簇）和denv [Pr 15（E）的p15（E）抗原决定簇]编码的基因产物之间的相互作用，所述相互作用是有效病毒组装所需的（M. Satake和R. B。Luftig，1983，Virology 124，259-273），和（ii）浅蓝菌素抑制一种或多种负责Pr 65 gag和Pr 80 env裂解的蛋白水解酶。
Cerulenin, an inhibitor ofde novofatty acid (and cholesterol) biosynthesis, has been shown to significantly decrease (>75%) the amount of Moloney murine leukemia virus (M-MuLV) released into the culture medium of chronically infected mouse fibroblasts (I. Katoh, Y. Yoshinaka, and R. B. Luftig, 1986,Virus Res., in press). In order to clarify the mechanism by which this decrease in virus production occurs, we analyzed the kinetics ofgagandenvcoded protein synthesis in M-MuLV infected, cerulenin-treated cells by immunoprecipitation with monospecific antisera to p30, p12, p10, gp70, and p15(E). We found that in pulse (15 min-2 hr)-chase (0–4 hr) experiments the cleavage of not only Pr65gagto p30 and othergagcoded proteins but Pr80envto gp70 and Pr15(E) as well, was greatly reduced by cerulenin treatment. Further, since the total amount of label in the Pr65gagand Pr80envbands remained about the same or was slightly decreased in 2-hr pulsed, cerulenin-treated cells, this suggests that cerulenin decreases virus production, in part, by inhibiting the cleavage of both precursorgagandenvcoded polyproteins during virus assembly and budding at the cell membrane.We also observed that at longer chase periods (4 hr), the effect of cerulenin could be partially overriden in that minor amounts of cleavedgagandenvcoded polyproteins were produced and assembled into virion particles. However, these particles contained abnormally large amounts of the uncleaved precursor Pr65gag, suggesting that maturation was incomplete.The above results suggest two independent, but not exclusive, possible mechanisms of cerulenin action to block M-MuLV production, viz. (i) cerulenin decreases the pool of fatty acids, thereby inhibiting fatty acid acylation of Pr65gag, as well as Pr80env, and thus preventing the interaction betweengag(the p15 antigenic determinant on Pr65gag) andenv[the p15(E) antigenic determinant of Pr15(E)] coded gene products at the cell membrane needed for efficient virus assembly (M. Satake and R. B. Luftig, 1983,Virology124, 259–273), and (ii) cerulenin inhibits one or more proteolytic enzymes responsible for the cleavage of Pr65gagand Pr80env.