The characterisation of the virion RNA of avian Infectious Bronchitis Virus

The genomes of three coronaviruses

“…Furthermore, at least 25-30% of these RNAs contain covalently-bound poly(A) tracts of about 70 nucleotides in length located at or near the 3'-termini of the molecules. This and previous data [3,4,7,9,10], together with data showing that these genomes are infectious [4,9] and that there is no virion transcriptase [4,10], strongly suggest that the coronavirus genome is of positive polarity. These results are important for a number of reasons.…”

“…IBV Beau was grown in confluent primary chick kidney cell cultures and labelled with [3H]uridine or t3H]adenosine as in [3] . HCV 229E was grown in confluent monolayer cultures of continuous MRC cells and labelled with [3H] uridine or [3H] adenosine [7] .…”

“…At 32 h after infection the cells were harvested and subjected to 3 freeze-thaw cycles. The virus preparations were purified on sucrose gradients and labelled virus particles with typical coronavirus morphology were obtained in peak fractions of density 1 .I 8 g/ml coincident with peaks of infectivity [3,7] .…”

“…In this paper, studies on the characteristics of the genomes of HCV strain 229E (HCV 229E) and IBV strain Beaudette (IBV Beau) reported in [3,7] are extended, and the structure of the genome of another coronavirus, mouse hepatitis virus strain 3 (MHV 3) is analysed for the first time. A comparison of the results shows a much greater similarity between coronavirus genomes than has been previously observed.…”

Ribonucleoprotein of Avian Infectious Bronchitis Virus

“…wt. reported to vary from 5.6 x 106 to 9.0 × 106 (Watkins et al, 1975;Lomniczi & Kennedy, 1977;Macnaughton & Madge, 1977b;Schochetman et al, 1977;Macnaughton, 1978). The variation in tool.…”