病毒样颗粒(virus like particles,VLPs)是一种模拟病毒的颗粒形态特点,将外源基因片断产物呈递到病毒颗粒表面而形成的嵌合颗粒。它有与病毒颗粒相同的外部形态,甚至还有某些病毒受体的天然配体,同时还可将其他病原的特异性抗原等呈递...病毒样颗粒(virus like particles,VLPs)是一种模拟病毒的颗粒形态特点,将外源基因片断产物呈递到病毒颗粒表面而形成的嵌合颗粒。它有与病毒颗粒相同的外部形态,甚至还有某些病毒受体的天然配体,同时还可将其他病原的特异性抗原等呈递在自己的表面,因而在病原体的疫苗研究和基因治疗研究中发挥着重要的作用。目前研究得较多的病毒样颗粒有HIV gag颗粒、HBc颗粒、HBs颗粒、酵母Ty颗粒等等,其中HBc VLP较受人注目。 HBc有自动组装的特性,其形成的核心颗粒有显著刺激B细胞、T辅助细胞及细胞毒T细胞产生免疫反应的能力,而且HBc颗粒在人体内没有细胞毒性作用,再加上HBc容许插入外源片段并可保持或增强外源蛋白的免疫活性,基因表达的杂合蛋白在多种表达体系中都具备颗粒形成能力,且形成的颗粒易于纯化制备。以HBc为载体的疫苗生产研究、基因治疗方法研究在国外日益受到重视。现将有关这方面的研究进展简述如下。展开更多
The structure of the nuclosome core particle of chromatin in chicken erythrocytes has been examined by usingAFM. The 146 hp of DNA wrapped twice around the corehistone octamer are clearly visualized. Both the ends ofe...The structure of the nuclosome core particle of chromatin in chicken erythrocytes has been examined by usingAFM. The 146 hp of DNA wrapped twice around the corehistone octamer are clearly visualized. Both the ends ofentry/exit of linker DNA are also demonstrated. The dimension of the nucleosome core particles is- 1-4 um inheight and ～13-22 um in width. In addition, superbeads(width of - 48-57 urn, beight of-2-3 nm) are occasionallyrevealed, two turns of DNA around the core particles arealso detected.展开更多
文摘The structure of the nuclosome core particle of chromatin in chicken erythrocytes has been examined by usingAFM. The 146 hp of DNA wrapped twice around the corehistone octamer are clearly visualized. Both the ends ofentry/exit of linker DNA are also demonstrated. The dimension of the nucleosome core particles is- 1-4 um inheight and ～13-22 um in width. In addition, superbeads(width of - 48-57 urn, beight of-2-3 nm) are occasionallyrevealed, two turns of DNA around the core particles arealso detected.
