Abstract

RNA trans-splicing occurs in a wide range of eukaryotes, from protozoa to chordates. Here, the study presents the discovery of a spliced-leader (SL) RNA in the zoonotic trematode, Schistosoma japonicum. The 36-nucleotide SL in S. japonicum was derived from a 90-nucleotide non-polyadenylated RNA transcript encoded by 55 copies of SL genes dispersed throughout the genome. Differential transcription patterns of the SL gene among the parasite developmental stages were observed, indicating that trans-splicing may be a mechanism of post-transcriptional gene regulation in S. japonicum. Further, the distribution of SL genes in the genomes of S. mansoni and S. japonicum has been found to be very different, though the two parasites have been believed to be genetically close. These data open up a novel avenue for study on parasite biology linked to schistosomiasis, a disease affecting more than 200 million people world-wide.

Key words: Schistosoma mansoni, S. japonicum, spliced leader RNA, trans-splicing, gene regulation.