ÿþ<HTML><HEAD><TITLE>25º Congresso Brasileiro de Microbiologia </TITLE><link rel=STYLESHEET type=text/css href=css.css></HEAD><BODY aLink=#ff0000 bgColor=#FFFFFF leftMargin=0 link=#000000 text=#000000 topMargin=0 vLink=#000000 marginheight=0 marginwidth=0><table align=center width=700 cellpadding=0 cellspacing=0><tr><td align=left bgcolor=#cccccc valign=top width=550><font face=arial size=2><strong><font face=Verdana, Arial, Helvetica, sans-serif size=3><font size=1>25º Congresso Brasileiro de Microbiologia </font></font></strong><font face=Verdana size=1><b><br></b></font><font face=Verdana, Arial,Helvetica, sans-serif size=1><strong> </strong></font></font></td><td align=right bgcolor=#cccccc valign=top width=150><font face=arial size=2><strong><font face=Verdana, Arial, Helvetica, sans-serif size=1><font size=1>ResumoID:708-2</font></em></font></strong></font></td></tr><tr><td colspan=2><br><br><table align=center width=700><tr><td>Área: <b>Genética e Biologia Molecular ( Divisão N )</b><p align=justify><strong> ANALYSIS OF THE 1.3-BETA-GLUCAN SYNTHASE AND CHITIN SYNTHASE 4 PROMOTER REGIONS OF PARACOCCIDIOIDES BRASILIENSIS </strong></p><p align=justify><b>Daniella de Sousa Moares </b> (<i>UnB</i>); <b><u>Thiago Machado Mello de Sousa </u></b> (<i>UnB</i>); <b>Lorena da Silveira Derengowiski </b> (<i>UnB</i>); <b>Letícia Araujo Menezes Sant'ana </b> (<i>UnB</i>); <b>Ildinete Silva Pereira </b> (<i>UnB</i>); <b>Marcio José Poças Fonseca </b> (<i>UnB</i>)<br><br></p><b><font size=2>Resumo</font></b><p align=justify class=tres><font size=2> Paracoccidioides brasiliensis, the etiological agent of paracoccidioidomycosis (PCM), is a thermal dimorphic fungus which grows as a mycelium at room temperature and differentiates to yeast in cultures at 37°C and in the host tissue. The dimorphic transition of P. brasiliensis is associated with changes in the cell wall. When the fungus differentiates from mycelium to yeast, the chitin content is increased and the composition of glucan changes, reducing the 1,3-beta-glucan content and enhancing the content of 1,3-beta-glucan. In P. Brasiliensis, one homologous of 1,3-beta-glucan synthase gene (Pbfks1) and six genes of chitin synthase (Pbchs1, Pbchs2, Pbchs3, Pbchs4, Pbchs5 e Pbchs6) were identified. In our study, we investigated the promoter region of Pbfks1 and Pbchs4 genes. By means of electrophoretic mobility shift assay (EMSA), we analyzed probes referring to promoters of these two genes and we identified probable regulatory sites. In the attempt to analyze the promoter function of the Pbchs4 gene, a DNA fragment containing the promoter region of this gene was cloned and transformed in A. nidulans using lacZ as the gene reporter. The transformants were cultivated in medium containing different sources of carbon. Additionally, by means of quantitative real time RT-PCR, we analized the expression of Pbfks1 gene in medium with acetate or in medium with glucose as a carbon source. The analysis of the promoter region of the Pbfks1 gene indicates one TATA Box that could be functional, and we propose that the Pbchs4 promoter may be regulated by the stress responsive elements (STRE). Furthermore, we also demonstrated that the PacC DNA binding-domain of P. brasiliensis recognizes one A. nidulans's PacC described site, nevertheless, the protein didn't recognize one variation in the consensus sequence in the Pbchs4 promoter. The results from the reporter gene assay suggest that the chitin precursor, N-acetylglucosamine, activates the promoter of Pbchs4 gene. Additionally, results of qRT-PCR disclosed that Pbfks1 gene is more expressed in medium with acetate then in medium with glucose as a carbon source, similar to that described to S. cerevisiae. Therefore, the work developed in our research group provides data which may contribute for the comprehension of 1.3-beta-glucan synthase and chitin synthase 4 promoters' regulation in P. brasiliensis. </font></p><br><b>Palavras-chave: </b>&nbsp;Paracoccidioides brasilienses, promoter analysis, cell wall</td></tr></table></tr></td></table></body></html>