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

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.