Distinct histone modification profiles at transcription start sites during development of the parasite Trypanosoma cruzi.
(English)Manuscript (Other academic)
The parasite Trypanosoma cruzi is the etiological agent causing Chagas' disease in Central and South America. This protozoon presents a complex life cycle that comprises three major developmental stages as the parasite is transmitted from the invertebrate vector to a mammalian host. Such drastic environmental changes demand rapid adjustment of the parasite cellular processes. This adaptation appears to be mainly achieved by regulating gene expression levels through post-transcriptional processes. We have previously shown the important role of chromatin in regulating transcriptional initiation through histone modifications. Histones typically associated with active chromatin states (i.e. histone acetylation and histone H3 trimethylated K4) were preferentially enriched at sequences directly flanking transcription start sites in the intergenic region between divergently transcribed polycistronic gene clusters. In this study, we compare acetylated histone H3 profiles in replicative (i.e. logarithmic epimastigotes) and non-replicative (i.e. stationary epimastigotes and trypomastigotes) parasite stages. Histone acetylation was found less abundant in non-replicative stages consistent with previous observations of diminished transcriptional activity in these stages and suggesting potential links between transcription and replication. This was also accompanied by possible changes in nucleosome positioning. We also report the epigenetic profile of histone H3 trimethylated K36, a histone modification previously uncharacterized in T. cruzi . This histone mark was found enriched at regions of transcriptional initiation, suggesting a rather distinct function compared with its established roles in other organisms.
Trypanosoma cruzi; histone modifications; bidirectional transcription
IdentifiersURN: urn:nbn:se:uu:diva-100264OAI: oai:DiVA.org:uu-100264DiVA: diva2:210555