Transcription regulation of the Pbgp43 gene by nitrogen in the human pathogen Paracoccidioides brasiliensis

We show indirect evidences for the possible involvement of NIT2-like binding motifs in transcription modulation of the PbGP43 gene, which codes for an important antigen from the human fungal pathogen Paracoccidioides brasiliensis. This investigation was motivated by the finding of 23 NIT2-like sites within the proximal −2047 nucleotides of the PbGP43 5′ intergenic region from the Pb339 isolate. They compose four clusters, two of them identical. We found four NIT2-containing probes that were positive in electrophoretic mobility shift assays and further analyzed them. PbGP43 could be modulated by nitrogen primary sources in Pb339, Pb3 and Pb18 isolates, as observed by reverse transcription (RT) real time-PCR. Gene reporter assays conducted in Aspergillus nidulans suggested that the minimal fragment responsible for nitrogen modulation lies within −480 bp of the PbGP43 gene. This is the first report on PbGP43 transcription modulation in response to nitrogen primary sources, which might help understand its regulation during infection.