Analysis of chromosome number variation (aneuploidy) in Trypanosoma cruzi by FISH technique ("Fluorescence In Situ Hybridization").

• Grant number: 20/11585-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2021
• End date: June 30, 2022
• Field of knowledge: Biological Sciences - Parasitology - Protozoology of Parasites
• Principal Investigator: José Franco da Silveira Filho
• Grantee: Agustina Belén Pauer
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Trypanosoma cruzi is a parasitic protozoan that shows remarkable genetic variability among strains and clones derived from the same strain, with significant differences in the genotypic and phenotypic traits, such as infectivity and pathogenicity patterns, as well as variations in the molecular karyotype. These changes may play an important role in the adaptive response in different hosts, mammalian and insect vectors. Several studies indicate the occurrence of aneuploidy in T. cruzi, even though it is considered a diploid organism. Evidence obtained from microarray comparative genomic hybridization (aCGH) and new generation sequencing (NSG) showed the presence of chromosomes with different ploidy (monosomic to tetrasomic) in the same population. Data from our laboratory also demonstrated the presence of segmentar aneuploidy in T. cruzi, more specifically between the parental strain G and clone D11. Aneuploidy may be an important factor in generating genetic variability in T. cruzi, an organism that reproduces asexually and shows a predominant clonal evolution. The objective of this project is to identify aneuploid events in T. cruzi by the FISH technique using the Spliced Leader Sequence (spliced leader mini-exon transcript" or "spliced leader sequence) as markers of chromosome aneuploidy in the clone CL Brener. The "Spliced Leader Sequence" (SL) or mini-exon gene is an essential gene in trypanosomatids. It encodes a small RNA (Leader Sequence) that is added at the 5 'end of all mRNAs of T. cruzi and other trypanosomatids. The rationale behind this choice was to investigate the presence of aneuploidy in an essential parasite gene. FISH allows the evaluation of ploidy in an individual cell, and therefore, will be used here to investigate the presence of aneuploidy the cell population. It is expected with this analysis to verify the presence of aneuploidy in the chromosomes harboring the Spliced Leader Sequence of clone CL Brener.