Preliminary studies on the isolation of coronavirus 229E nucleocapsids

Ribonucleoprotein of Avian Infectious Bronchitis Virus

“…of these structures was much larger than that of the linear strands (Fig. 4a, b) and similar to that of RNP complexes of HCV 229E Caul et al, 1979) and MHV3 , as seen on negative staining. It is tempting to speculate that these structures represent a stage in the uncoiling of an IBV RNP complex before linear strands are formed.…”

“…Occasionally, these RNPs formed helical structures (Fig. 4c), as described for HCV 229E (Kennedy & Johnson-Lussenburg, 1975/6;Macnaughton et al, 1978;Caul et al, 1979) and MHV3 , although they were usually found as long thin strands up to 6.7/zm in length (Fig. 3, Fig.…”

“…4a, b). Previous reports on the HCV 229E RNP using negative staining have indicated that although these RNPs are helical (Kennedy & Johnson-Lussenburg, 1975/6;Macnaughton et al, 1978;Caul et al, 1979), the helices may consist of tightly bound coils of 9 to 13 nm diam. (Caul et al, 1979) or of more loosely bound coils of 14 to 16 nm diam.…”

“…Helical ribonucleoprotein (RNP) structures, detected by negative staining, have been described for the coronaviruses, human coronavirus strain 229E (HCV 229E) (Kennedy & Johnson-Lussenburg, 1975/6;Macnaughton et al, 1978;Caul et al, 1979) and mouse hepatitis virus strain 3 (MHV3) . Furthermore, thread-like structures, which could represent RNP, have been observed in thin sections of particles of the eoronavirus, avian infectious bronchitis virus (IBV) (Apostolov et al, 1970) and associated with human enteric coronavirus (HECV) infections (Caul & Egglestone, 1977).…”

Molecular Interactions in the Assembly of Coronaviruses

“…Ultrastructural studies of nucleocapsids derived from purified virion preparations have shown quite a variety of helical structures, depending on the virus and the experimental conditions used. The overall feature, however, was that of a thread-like coil, sometimes appearing to be hollow, with a diameter varying between 9 and 16 nm and a length ranging from 0.32 mm up to 6 mm (Caul et al, 1979;Davies et al, 1981;Kennedy and Johnson-Lussenburg, 1975;Macnaughton and Davies, 1978) Biochemical analysis of nucleocapsids prepared by detergent disruption of purified coronaviruses revealed the presence of genomic RNA and N protein. Interestingly, however, particles obtained by treatment of virions with Nonidet P-40 appeared to be spherical when viewed under the electron microscope and, in addition, to contain M protein, as was observed with TGEV (Garwes et al, 1976), HEV (Pocock and Garwes, 1977), and MHV-JHM (Wege et al, 1979).…”