De B P, Thornton G B, Luk D, Banerjee A K
Proc Natl Acad Sci U S A. 1982 Dec;79(23):7137-41. doi: 10.1073/pnas.79.23.7137.
One of the major structural proteins of vesicular stomatitis virus is a small, nonglycosylated, matrix protein which associates with the nucleocapsid core during final stages of morphogenesis and budding. Biochemical and genetic studies suggested that the matrix protein regulates RNA synthesis both in vitro and in vivo. We have purified biologically active matrix protein from the virus and have directly shown that it significantly inhibits RNA synthesis in vitro mediated by the virion-associated RNA polymerase at low ionic strength (0.02 M). The inhibition was greater than 80% when the ratio of matrix protein to the major nucleocapsid protein in the transcribing complex was 2:1 (wt/wt). The inhibition was found to be at the level of RNA chain elongation and not at the initiation step. Electron microscopic studies revealed that inhibition of transcription by matrix protein was accompanied by a profound structural change of the transcribing nucleocapsid from an extended structure to a highly compact form. At higher ionic strength (0.12 M), the matrix protein failed to interact with the nucleocapsid. The matrix protein appears to be involved in condensing the nucleocapsid and blocking transcription during maturation of the virus particle.
水泡性口炎病毒的主要结构蛋白之一是一种小的、非糖基化的基质蛋白，它在形态发生和出芽的最后阶段与核衣壳核心结合。生化和遗传学研究表明，该基质蛋白在体外和体内均调节RNA合成。我们已从病毒中纯化出具有生物活性的基质蛋白，并直接证明它在低离子强度（0.02M）下能显著抑制由病毒体相关RNA聚合酶介导的体外RNA合成。当转录复合物中基质蛋白与主要核衣壳蛋白的比例为2:1（重量/重量）时，抑制率大于80%。发现这种抑制作用发生在RNA链延伸水平，而非起始步骤。电子显微镜研究显示，基质蛋白对转录的抑制伴随着转录核衣壳从伸展结构向高度紧凑形式的深刻结构变化。在较高离子强度（0.12M）下，基质蛋白无法与核衣壳相互作用。基质蛋白似乎在病毒颗粒成熟过程中参与凝聚核衣壳并阻断转录。
