In-depth analysis of the location of replication origins and the putative component of the Orc1b origin recognition complex in the genome of Trypanosoma cruzi

• Grant number: 23/03260-5
• Support Opportunities: Scholarships in Brazil - Master
• Start date: December 01, 2023
• End date: November 30, 2025
• Field of knowledge: Biological Sciences - Parasitology - Protozoology of Parasites
• Principal Investigator: Maria Carolina Quartim Barbosa Elias Sabbaga
• Grantee: Ruana de Paula Freitas
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated research grant: 20/00694-6 - How DNA replication contributes for the success of infection caused by Trypanosoma cruzi, AP.TEM

Abstract

DNA replication is essential for cell replication, and therefore it is a complex and tightly controlled process. Problems in the DNA replication process can lead to gene mutation, recombination and amplification or deletion events. DNA replication starts in genomic regions named replication origins that are recognized in eukaryotes by the heterohexamer Origin Recognition Complex (ORC). According to activation frequency, origins are classified as constitutive, flexibles and dormants. The three classes of origins were identified by our group in Trypanosoma cruzi and four of six components of ORC were also described in Trypanosoma. A fifth component, Orc1b, was identified binding ORC, but not during the entire cell cycle, raising doubts concerning (i) the involvement of Orc1b with ORC and (ii) what is the function of Orc1b in the replication process. Different strains of T. cruzi parasite present variations in their genetic composition, repetitive sequences and multigenic families, which play an important role in the host's infection process. Since DNA replication can cause genetic variability and genomic alterations, our group seeks to investigate how DNA replication contributes to genomic changes in this parasite. The first objective of this work is to deepen the previous knowledge of the location of different classes of origins in the different genomic regions. From the analysis of data previously generated through the techniques of MFA-seq, ChIP-seq and D-NAscent, we intend to evaluate the location of the origins in the different chromosomes, if the origins of replication are located in conserved or quickly evolving genomic regions. Since previous data from our group identified origins within open reading frames, we intend to evaluate whether these regions are genes or pseudogenes. The second objective of this work is to investigate the possible component of ORC, Orc1b, in order to evaluate its co-location with the ORC component Orc1Cdc6 and its distribution in the different classes of origins.