三角帆蚌瘟病病毒的精细结构与基因组及多肽的研究

FINE STRUTURE, GENOME AND POLYPEPTIDES OF THE MUSSEL HYRIOPSIS CUMINGII PLAGUE VIRUS

从自然发病蚌分离的三角帆蚌瘟病病毒(Hyriopsis cumingii Plague Virus,HcPV)呈球形或多形态,直径40～210nm。病毒外被厚7.9nm的脂质囊膜,表面布满长12nm的棒状突起,内嵌有20nm的砂样颗粒。核衣壳由串珠状物构成。在包装入病毒前呈杆形核衣壳,直径约12nm,长度30～340nm不等。以后经3～5个圈的螺旋化,成为直径40～70nm的螺线管核衣壳,包装在病毒中。病毒基因组由33S,28S、22S、18S和5S等5个分节段的单链RN A组成,其中33S和22S RNA结合于核衣壳中,为病毒特异性基因片段。4个大片段RNA的分子量分别为2.4、1.9、1.2和0.7×10~6D。病毒多肽组分有4个,分子量为VP1 46kD,VP2 41kD,VP339kD,VP4 18kD。其中VP1为非糖基化的核蛋白,是核衣壳的多肽成分,VP2和VP3为糖肽,分别构成囊膜及囊膜外突起。VP4的含量较低。

The Hyriopsis cumingii Plague Virus ( HcPV ) particles which were fo-und in field infected mussels are round shaped or pleiomorphic particles which range widely in diameter from 40-2lonm. The virus particles are cbaracterized by a lipid envelope of about 7.9nm in thickness and a layer of club shaped surface projections of about 12nm in length. The interior of the virus particles contain a variable number of 20nm eletron-dense granules. The nucleocapsid, before being encapsulated into the virus envelope, appears like string-of-beads 12nm in diameter and 30-340nm in length. It may be further convoluted into coils of 3-5 circles with a total diameter of 40-70nm and then packed into the virus. The virai genome consists of 5 segments of single-stranded RNA with the estimated size of 33S, 28S, 22S, 18S and 5S. The 33S and 22S RNA are thought to represent the specific genomic RNA of the virus by the fact that they combine with the nucleocapsid. The molecular weights of the four major RNA speices has been estimated to be 2.4, 1.9, 1.2, and o.7xlo'D respectively.SDS-PAGE of purified virus reveals the presence of 4 polypeptides with estimated molecular weights of VP1 46, VP2 41, VP3 39 and VP4 18kd. Am-ong them, VPl is the major protein component, it is a nonglycosylated nucleoprotein associated with the nucleocapsid. While VP2 and VP3 are glycopeptides located on the surface projectfons and envelope respectively. Minor polypeptide of VP4 is also routinely observed.