Study in the transcription start and terminal sites of RNA polymerase II from Trypanosoma cruzi

• Grant number: 19/16033-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date until: November 01, 2021
• End date until: March 31, 2023
• Field of knowledge: Biological Sciences - Parasitology - Protozoology of Parasites
• Principal Investigator: Julia Pinheiro Chagas da Cunha
• Grantee: Juliana Nunes Rosón
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated research grant: 18/15553-9 - Going deeper into Trypanosoma cruzi chromatin regulation: identifying new players and quizzing its impact on a potential transcription control, AP.JP2

Abstract

Trypanosoma cruzi is a flagellate that causes Chagas Disease. It transits between vertebrate and invertebrate hosts, alternating constantly between replicative and infective forms. As a Trypanosomatide, it has particularities in its molecular biology, such as the transcription of large polycistronic regions. Specific promoter regions for each gene have not been described yet, indicating that gene expression regulation takes place mainly at the post-transcriptional level. Global transcription studies have shown different transcription levels between life forms, which are accompanied by changes in chromatin conformation. Epigenetic marks, like histones variant, are present in the trypanosomatids' chromatin and are mainly enriched in the initiation and termination transcription regions. Our group identified by quantitative proteomics a variant of the histone H2B - H2B.V that is increased in infective forms of T. cruzi. In the present study, we aimed to identify the beginning and ending transcription regions of this organism, using ChIP-seq of chromatin-associated proteins (H2B.V, H3, RPB9 - subunit of RNA pol II, and H4.V) and a nascent transcript assays. In the beginning of the applicant's PhD, H2B.V and H3 ChIP-seq assays were performed, and enrichment was detected in dSSRs, tDNAs and regions between conserved (mainly protein-coding genes) and disrupted (non-synthetic regions, mainly virulence factors). To complete the doctoral project, in this project proposal, we intend to generate parasites expressing RPB9 (an RNA Pol II subunit) and H4.V with ty1-tag by CRISPR Cas9 to investigate their genomic localization by ChIP-seq assays. Finally, we will compare these results with data from nascent transcripts assays (GRO-seq). We believe this project will better clarify the mechanisms of transcription regulation, in addition to determine accurately the start and ending transcription regions in T. cruzi. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

ROSON, JULIANA NUNES; VITARELLI, MARCELA DE OLIVEIRA J.; COSTA-SILVA, HELLIDA MARINA; PEREIRA, KAMILLE SCHMITT; PIRES, DAVID DA SILVA; LOPES, LETICIA DE SOUSA; CORDEIRO, BARBARA; KRAUS, AMELIE; CRUZ, KARIN NAVARRO TOZZI; CALDERANO, SIMONE GUEDES; et al. 2B.V demarcates divergent strand-switch regions, some tDNA loci, and genome compartments in Trypanosoma cruzi and affects parasite differentiation and host cell invasio. PLOS PATHOGENS, v. 18, n. 2, FEB 2022. (18/15553-9, 16/50050-2, 17/06104-3, 19/04483-2, 19/16033-1, 13/07467-1, 19/19834-5)