Characterization of a granulosis virus from the castor semilooper, Achaea janata L

The granulosis virus isolated from Achaea janata is composed of capsules (463 +/- 25 x 280 +/- 22 nm) which contain single virus particles. The virus particles (274 +/- 9 x 95 +/- 4 nm) contain nucleocapsids (297 +/- 7 x 52 +/- 2 nm) within an envelope. The empty capsids measured 265 +/- 9 x 63 +/- 3 nm. SDS-PAGE electrophoresis was carried out and the granulin polypeptide (28.9 +/- 0.5 kDa) was found to contain two other associated polypeptides of molecular weight 58.2 +/- 2.3 and 55.2 +/- 1.3 kDa, respectively. Protein gel electrophoresis of granulin gave degradation products from 27.2 to 15.4 kDa, when protease associated with capsules was not inhibited. The virus particles were found to contain 16 polypeptides with molecular weights ranging from 106.4 +/- 2.1 to 15. 5 +/- 0.8 kDa and 12 of these polypeptides were contained in the nucleocapsids. The major polypeptide of the capsids had molecular weight of 34.9 +/- 0.3 kDa. Restriction profiles of viral DNA with seven enzymes were obtained and the average molecular weight was found to be approximately 92 +/- 7 kb. Southern hybridization of the restriction profiles of the viral DNA with SalI fragment from pUCTnGV (containing granulin gene) was performed and hybridization was found on single discrete fragments with molecular weights ranging from 12.0 to 2.7 kb. The GC content of AjGV DNA was found to be 65 +/- 1% and the genome size as determined from reassociation kinetics was 92 kb.