DNA components of Tipula iridescent virus

Abstract

Purified Tipula iridescent virus (TIV) from infected Galleria mellonella larvae was shown to consist of four DNA components: L (> 150 kilobase pairs (kbp)), S1 (10.8 kbp), S2 (~6 kbp), and S3 (~3.5 kbp). Analysis of the DNA from sucrose gradient fractionated TIV revealed that the fractions corresponding to partially filled virions have less of L relative to S1. All S components are related to L. S1 and S2 are the most similar, while S3 is a subset of S2. Three recombinant plasmids were isolated from a TIV DNA bank constructed in the BamHI site of pBR322. Two plasmids, pTB19-76 and pTB18-110, are related to S1 and S2 and they contain viral sequences that are repeated in the TIV genome. The third plasmid pTBR1-10 is related to S3. At least part of the variation in TIV genome size (174–246 kbp) obtained by summation of restriction endonuclease derived DNA fragments can be accounted for by the presence of the S components and sequence repetition.