Exploring the Schistosoma mansoni adult male transcriptome using RNA-seq

Schistosoma mansoni is one of the agents of schistosomiasis, a chronic and debilitating disease. Here we present a transcriptome-wide characterization of adult S. mansoni males by high-throughput RNA-sequencing. We obtained 1,620,432 high-quality ESTs from a directional strand-specific cDNA library, resulting in a 26% higher coverage of genome bases than that of the public ESTs available at NCBI. With a 15×-deep coverage of transcribed genomic regions, our data were able to (i) confirm for the first time 990 predictions without previous evidence of transcription; (ii) correct gene predictions; (iii) discover 989 and 1196 RNA-seq contigs that map to intergenic and intronic genomic regions, respectively, where no gene had been predicted before. These contigs could represent new protein-coding genes or non-coding RNAs (ncRNAs). Interestingly, we identified 11 novel Micro-exon genes (MEGs). These data reveal new features of the S. mansoni transcriptional landscape and significantly advance our understanding of the parasite transcriptome.

Graphical abstractRNA-seq of Schistosoma mansoni adult male transcriptome provided high-quality sequence information to improve gene structure annotationDownload full-size imageHighlights► RNA-seq of Schistosoma mansoni adult male with 15×-deep coverage of transcribed genome bases. ► RNA-seq ESTs help to correct gene prediction exons in the genome annotation. ► Nine hundred and ninety predictions without previous evidence of expression were confirmed by ESTs. ► Intergenic and intronic genomic regions with novel evidence of transcription. ► Identification of 11 novel Micro-exon genes (MEGs).