Análise da expressão de genes envolvidos na manutenção da homeostase de cobre no patógeno humano Paracoccidioides brasiliensis

• Autor(a) principal: SANTOS, Rodrigo da Silva
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/001300000d8sm
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tde/1270
• topic: cobre, Paracoccidioides brasiliensis, expressão gênica e infecção; copper, Paracoccidioides brasiliensis, gene expression and infection; CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA::BIOLOGIA MOLECULAR

The fungus Paracoccidioides brasiliensis is a human pathogen with a wide distribution in Latin America. The fungus causes paracoccidioidomycosis when mycelia reachs the lungs. The success of the infection depends on the acquisition of essential micronutrients such as copper, which is required as cofactor for a variety of enzymes important in biological in several processes, such as respiration, growth and acquisition of iron. Previous studies, of the Laboratory of Molecular Biology showed that a high affinity copper transporter (PbCTR3) is a molecule highly expressed and probably necessary for the infection establishment of by P. brasiliensis. In the present study were isolated and characterized the genomic and cDNA sequences encoding for PbCTR3 of P. brasiliensis. The cDNA presented 582 base pairs and encodes for a protein with 193 amino acids, predicted molecular mass of 21.5 kDa and pI of 8.6. The genomic sequence has four exons interrupted by three introns. In silico analysis was performed on the database of the structural genome of P. brasiliensis (http://www.broad.mit.edu/annotation/genome/paracoccidioides_brasiliensisMultiHome.html) , where genes involved in maintaining the homeostasis of copper have been identified and used to design of a model of copper homeostasis in P. brasiliensis. The transcriptional behavior of Pbctr3 and genes involved in copper homeostasis were examined during exposure of yeast cells of P. brasiliensis to copper and iron depletion conditions, by real time qRTPCR. It was demonstrated a significant change in transcription lovel those of genes in the absence of copper, as well as in the combined absence of both metals. qRT-PCR was used to analyze the expression of Pbctr3 and Pbcrp (which encodes a protein responsive to copper) in yeast cells of P. brasiliensis derived from infected lungs and spleen at different time points of infection. The expression of Pbctr3 and Pbcrp was super-regulated during experimental infection. Taken together, these data suggest the importance of PbCtr3 and of absorbing copper / iron during the infectious process