The Genome-wide nucleosome positions in Trypanosoma brucei procyclic and Bloodstream forms

[摘要] English: The epigenome represents a major regulatory interface to the eukaryotic genome. Nucleosome positions, histone variants, histone modifications and chromatin associated proteins all play a role in the epigenetic regulation of DNA function. Trypanosomes, an ancient branch of the eukaryotic evolutionary lineage, exhibit some highly unusual transcriptional features, including the arrangement of functionally unrelated genes in large, polymerase II transcribed polycistronic transcription units, often exceeding hundreds of kb in size. It is generally believed that transcription initiation plays a minor role in regulating the transcript level of genes in trypanosomes, which are mainly regulated posttranscriptionally. Recent advances have revealed that epigenetic mechanisms play an essential role in the transcriptional regulation of Trypanosoma brucei. This suggested that the regulation of gene activity is, indeed, an important control mechanism, and that the epigenome is critical in regulating gene expression programs that allow the successful migration of this parasite between hosts, as well as the continuous evasion of the immune system in mammalian hosts. A wide range of epigenetic signals, readers, writers and erasers have been identified in trypanosomes, some of which have been observed to be unique to trypanosomes. We review recent advances in our understanding of epigenetic control mechanisms in T. brucei, the causative agent of African sleeping sickness, and discuss the possible role that these mechanisms may play in the life cycle of the parasite.

[发布机构] University of the Free State