The granulin gene region of Cryptophlebia leucotreta granulosis virus: sequence analysis and phylogenetic considerations.

The nucleotide sequence of a 2.2 kb genome region of the baculovirus Cryptophlebia leucotreta granulosis virus (CIGV) encompassing the granulin gene and a second open reading frame, designated ORF909, was determined. The putative granulin ORF comprises 744 nucleotides encoding a polypeptide with a predicted M(r) of 29.3 K. The 5' leader of the granulin gene contains a canonical late baculovirus promoter (ATAAG) and differs only in two nucleotide positions from the sequence of Cydia pomonella granulosis virus (CpGV). Sequence comparison with the granulin genes of different granulosis viruses indicated a very close relationship between CIGV and CpGV of about 96% amino acid identity. ORF909 is 909 nucleotides in length and encodes a potential protein of M(r) 36.2K. It contains two zinc finger-like motifs, similar to ME53, which was previously described for Autographa californica multiple nucleocapsid nuclear polyhedrosis virus. ORF909 protein is significantly shorter than ME53 protein, lacking more than 105 amino acids of the amino terminus of ME53. Both genes contain an early and a late promoter motif suggesting a similar temporal regulation. Homologous sequences to ORF909 are also present upstream of the granulin genes of other granulosis viruses (GVs) indicating that this ORF is common in GVs.