Comparative analysis of the granulin regions of the Phthorimaea operculella and Spodoptera littoralis granuloviruses

The nucleotide sequence of two cloned restriction fragments encompassing th e granulin genes from the granuloviruses of the potato tuber moth, Phthorim aea operculella, PhopGV, and the Egyptian cotton leaf worm, Spodoptera litt oralis, SpliGV, have been determined. Although both viruses are able to infect the same Ph. operculella cell line , their granulins do not cluster in the same phylogenetic branches. PhopGV ganulin is closely related to Cydia pomonella GV (CpGV) and Cryptophlebia l eucotreta GV (ClGV) (95.2 and 94% identity at the aminoacid level), while S pliGV granulin falls close to Trichoplusia ni GV and Xestia c-nigrum GV (91 .6 and 92.0% respectively). The gene organization around the granulins reflects this clustering. Upstre am the PhopGV granulin, an ORF belonging to the ME53 gene family (as ORF 12 4R of CpGV and 909 of ClGV) is present, while no equivalent ORF is found in this region in SpliGV. Downstream the granulin, both viruses present a gen e homologous to the Autographa californica nucleopolyhedrovirus (AcMNPV) OR F 9 followed by a Protein Kinase (AcMNPV ORF10). The structure of this regi on seems thus conserved not only among nucleopolyhedroviruses but also in a t least some granuloviruses.