Heterochromatin protein 1 (HP1) of Schistosoma mansoni : non-canonical chromatin landscape and fitness effects

Heterochromatin protein 1 (HP1) is widespread in several organisms playing a role in control of gene expression by heterochromatin formation and maintenance of silent chromatin. Schistosoma mansoni is a human parasite that is responsible for Schistosomiasis, a tropical neglected disease in the tropical and subtropical areas in the world, where the intermediate host Biomphalaria glabrata is present. In this study we attempted to investigate if the Sm HP1 is enriched in S. mansoni chromatin in cercariae larvae stage, compared with another larvae stage sporocysts and it’s importance for S. mansoni life cycle progression and parasite fitness. We used ChIPmentation with commercial antibody ab109028 that passed in-house quality control. Our data show that S. mansoni HP1 enrichment is non-canonical with a peak at the transcription end sites of protein coding genes. We did not find strong differences in Sm HP1 chromatin landscapes between sporocysts and cercariae. Knock-down of Sm HP1 in schistosomula and in vivo experiments in mice unexpectedly increased parasite fitness. Our results suggest that Sm HP1 may influence chromatin structure in a non-canonical way in S. mansoni stages and may play a role in regulation of parasite fitness.