H2B.V demarcates divergent strand-switch regions, some tDNA loci, and genome compartments in Trypanosoma cruzi and affects parasite differentiation and host cell invasion

Nunes Roson, Juliana; Oliveira Vitarelli, Marcela de; Costa-Silva, Hellida Marina; Pereira, Schmitt Kamille; Silva Pires, David da; Sousa Lopes, Leticia de; Cordeiro, Barbara; Kraus, Amelie; Navarro Tozzi Cruz, Karin; Guedes Calderano, Simone; Fragoso, Stenio Perdigao; Siegel, T. Nicolai; Elias, Maria Carolina und Cunha, Julia Pinheiro Chagas da (2022): H2B.V demarcates divergent strand-switch regions, some tDNA loci, and genome compartments in Trypanosoma cruzi and affects parasite differentiation and host cell invasion.
In: PLOS Pathogens 18(2), e1009694

Abstract

Author summaryTrypanosomatids have to adapt to different environmental conditions, changing their morphology, gene expression and metabolism. These organisms have many unique features in terms of gene expression regulation. The genomic organization includes polycistronic regions with the absence of well-defined transcription start sites. In T. brucei, histone variants mark the start and ending sites of transcription;however, little is known about whether these proteins change their genome location, expression levels and interactors along life forms and what the impact is of these changes on parasite differentiation and infection. In T. cruzi, the causative agent of Chagas disease, we previously found that the histone variant of H2B is enriched in TCT forms, a nonreplicative and infective form, suggesting that this variant may contribute to the differences in chromatin structure and global transcription rates observed among these life forms. Here, we aimed to go one step further and performed the first histone ChIP-seq analysis in T. cruzi, in which we found that H2B.V was enriched at divergent strand switch regions, some tDNA loci and other critical genomic regions associated with T. cruzi genome compartments. We found that H2B.V interacts with a bromodomain factor, suggesting an intricate network involving chromatin acetylation around H2B.V enriched sites. Moreover, parasites expressing reduced H2B.V levels were associated with higher rates of differentiation and mammalian cell infectivity. Histone variants play a crucial role in chromatin structure organization and gene expression. Trypanosomatids have an unusual H2B variant (H2B.V) that is known to dimerize with the variant H2A.Z generating unstable nucleosomes. Previously, we found that H2B.V protein is enriched in tissue-derived trypomastigote (TCT) life forms, a nonreplicative stage of Trypanosoma cruzi, suggesting that this variant may contribute to the differences in chromatin structure and global transcription rates observed among parasite life forms. Here, we performed the first genome-wide profiling of histone localization in T. cruzi using epimastigotes and TCT life forms, and we found that H2B.V was preferentially located at the edges of divergent transcriptional strand switch regions, which encompass putative transcriptional start regions;at some tDNA loci;and between the conserved and disrupted genome compartments, mainly at trans-sialidase, mucin and MASP genes. Remarkably, the chromatin of TCT forms was depleted of H2B.V-enriched peaks in comparison to epimastigote forms. Interactome assays indicated that H2B.V associated specifically with H2A.Z, bromodomain factor 2, nucleolar proteins and a histone chaperone, among others. Parasites expressing reduced H2B.V levels were associated with higher rates of parasite differentiation and mammalian cell infectivity. Taken together, H2B.V demarcates critical genomic regions and associates with regulatory chromatin proteins, suggesting a scenario wherein local chromatin structures associated with parasite differentiation and invasion are regulated during the parasite life cycle.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Tiermedizin > Veterinärwissenschaftliches Department
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 1553-7366
• Sprache: Englisch