title: Trypanosoma cruzi gene expression in response to gamma radiation.
abstract: Trypanosoma cruzi is an organism highly resistant to ionizing radiation. Following a dose of 500 Gy of gamma radiation, the fragmented genomic DNA is gradually reconstructed and the pattern of chromosomal bands is restored in less than 48 hours. Cell growth arrests after irradiation but, while DNA is completely fragmented, RNA maintains its integrity. In this work we compared the transcriptional profiles of irradiated and non-irradiated epimastigotes at different time points after irradiation using microarray. In total, 273 genes were differentially expressed; from these, 160 were up-regulated and 113 down-regulated. We found that genes with predicted functions are the most prevalent in the down-regulated gene category. Translation and protein metabolic processes, as well as generation of precursor of metabolites and energy pathways were affected. In contrast, the up-regulated category was mainly composed of obsolete sequences (which included some genes of the kinetoplast DNA), genes coding for hypothetical proteins, and Retrotransposon Hot Spot genes. Finally, the tyrosyl-DNA phosphodiesterase 1, a gene involved in double-strand DNA break repair process, was up-regulated. Our study demonstrated the peculiar response to ionizing radiation, raising questions about how this organism changes its gene expression to manage such a harmful stress.
authors.affiliation: Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Priscila
authors.initials: P
authors.lastname: Grynberg
authors.forename: Danielle Gomes
authors.initials: DG
authors.lastname: Passos-Silva
authors.forename: Marina de Moraes
authors.initials: Mde M
authors.lastname: Mourão
authors.forename: Roberto
authors.initials: R
authors.lastname: Hirata
authors.forename: Andrea Mara
authors.initials: AM
authors.lastname: Macedo
authors.forename: Carlos Renato
authors.initials: CR
authors.lastname: Machado
authors.forename: Daniella Castanheira
authors.initials: DC
authors.lastname: Bartholomeu
authors.forename: Glória Regina
authors.initials: GR
authors.lastname: Franco
mesh_terms: D015415:Biomarkers / Q000378:metabolism*; D018105:DNA, Kinetoplast / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D015870:Gene Expression / Q000528:radiation effects*; D020869:Gene Expression Profiling; D017125:Genes, Protozoan / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D014349:Trypanosoma cruzi / Q000235:genetics* / Q000254:growth & development
chemical_list: D015415:Biomarkers; D018105:DNA, Kinetoplast; D012333:RNA, Messenger