Differential sense and antisense expression profiles of Syrista parreyssi (Hymenoptera: Cephidae) mitochondrial transcripts

The transcription of the mitogenome shows a unique pattern that is both similar to and different from the nuclear and bacterial patterns. Mitochondrial transcription generates five polycistronic units from three promoters in Drosophila melanogaster, and different expression levels of genes were observed in both different and, interestingly, the same polycistronic units in D. melanogaster. This study was conducted to test this phenomenon in the mitogenome of Syrista parreyssi (Hymenoptera: Cephidae). RNA isolation and DNase digestion were performed using only one whole individual, and real-time polymerase chain reaction analyses were performed with complementary DNAs of 11 gene regions using gene-specific primers. It was found that the expression level of each gene exhibited differences from each other, and some genes (e.g., cox genes, and rrnS) were interestingly expressed at significant levels in the corresponding antisense chain. Additionally, the mitogenome of S. parreyssi was found to have the capacity to encode 169 additional peptides from 13 known protein-coding genes, most of which were encoded in antisense transcript units. One of the unique findings was a potential open reading frame sequence that was potentially encoded in the antisense rrnL gene and included a conserved cox3 domain.