Circular and elongated linear forms of measles virus nucleocapsid

Abstract

PARAMYXOVIRUSES are assuming increasing importance as possible causative agents of several human diseases^1,2. To date little is known about their mode of replication, although it has been suggested that the nucleocapsid replicates without extensive dissociation of the protein from the nucleic acid component³. Previous reports on the structure of nucleocapsids extracted from virions or infected cells, with or without further purification, have shown by electron microscopy that the molecules are linear, and although short pieces can be found, the majority are about 1.0 µm long⁴. We report here the occurrence of rare circular forms of measles nucleocapsid as well as linear molecules of greater than normal length.