Análises in vivo e in vitro de interações intermoleculares da Beta-1,3- glicanosiltransferase 1 de Paracoccidioides brasiliensis

• Autor(a) principal: BAILÃO, Elisa Flávia Luiz Cardoso
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tde/1282
• topic: Glicanosiltransferase, duplo híbrido e pull-down; Glucanosyltransferase, two hybrid and pull-down; CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA::BIOLOGIA MOLECULAR

The cell wall of pathogenic microbes acts as an initial barrier that is in contact with hostile environments. Besides functioning as a mechanical barrier, it harbours an immunogenic macromolecules arsenal. One of the ways that proteins can be associated to the cell wall, it is through GPI anchor. The hydrophobic C-terminal end of the β-1,3-glucanosyltransferase enzyme of the human pathogenic fungus Paracoccidioides brasiliensis is characteristic of GPI anchored proteins. The β-1,3-glucan assembling and rearrangement are essential since this molecule acts as a scaffold to support cell wall proteins and polysaccharides. In the thermodimorphic fungus P. brasiliensis, β-1,3-glucan is found predominantly in mycelium form and α-1,3-glucan is predominant in the yeast form. In this work, it was screened possible protein-protein interactions performed by β-1,3-glucanosyltransferase 1 of P. brasiliensis (PbGel1p). To obtain these results, a P. brasiliensis cDNA library was screened with PbGel1p using the Saccharomyces cerevisiae two hybrid system. In addition, pull-down assay was used as an in vitro complementary technique to isolate proteins that interact direct or indirectly with PbGel1p. It was screened 38 gene products using two hybrid system and it was identified 3 proteins using the pull-down assay associated with mass spectrometry. The PbGel1p role in the cell wall maintenance and remodeling was indicated through the analysis of screened interactions, like alpha-glucosides permease, acid phosphatase, GDSL lipase, septin, actin, tubulin, HSP90 and pyruvate kinase. Furthermore, nuclear localization of PbGel1p and its role in the locus-specific transcriptional silencing were suggested based on such interactions: Qde2 argonaute, transcription elongation factor spt6, others transcription factors and ATP-citrate synthase. Therefore, this study indicated, for the first time, that PbGel1p has multiple location and it participates either in roles classically described for glucanosyltransferases, as the cell wall remodeling, or in recently described functions for this family of proteins, as the locus-specific transcriptional silencing.