Expression of cDNA of the gene for the capsid protein VP2 of German cockroach densovirus in the transgenic strain of Drosophila melanogaster

Abstract

Transgenic strains of Drosophila melanogaster capable of expressing a cDNA fragment corresponding to open reading frame (ORF) of the gene for the German cockroach densonucleosis virus capsid protein VP2 (ORF VP2) in specific tissues and at a certain stage of development depending on the type of chosen driver strains (GAL–UAS system) were obtained. The ORF VP2 transcription was examined at the imago stage after crossing the obtained transgenic Drosophila with the driver strain expressing the inducer protein (GAL4) under control of actin promoter (the ORF VP2 expression is induced in all tissues of the firstgeneration Drosophila). It was demonstrated that the greater part of transcribed foreign RNA was represented by three spliced variants in which RNA fragments either between nucleotides 137 and 353 or between nucleotides 609 and 1925 were excised; the third spliced variant was represented by RNA lacking both introns. Using the next-generation sequencing (NGS) technique, the proportion of unspliced form relative to spliced variants of the analyzed RNA was assessed. It was shown that the ratio of unspliced form to the identified spliced variants of the analyzed RNA was approximately 1: 6. It is suggested that splicing of viral RNA foreign to Drosophila can be a sort of defense mechanism preventing the large-scale production of the capsid protein, potentially hazardous to the host organism.