The transcriptome analysis of early morphogenesis in Paracoccidioides brasiliensis mycelium reveals novel and induced genes potentially associated to the dimorphic process
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2007-04
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Background: Paracoccidioides brasiliensis is a human pathogen with a broad distribution in Latin America. The fungus is
thermally dimorphic with two distinct forms corresponding to completely different lifestyles. Upon elevation of the
temperature to that of the mammalian body, the fungus adopts a yeast-like form that is exclusively associated with its
pathogenic lifestyle. We describe expressed sequence tags (ESTs) analysis to assess the expression profile of the
mycelium to yeast transition. To identify P. brasiliensis differentially expressed sequences during conversion we performed
a large-scale comparative analysis between P. brasiliensis ESTs identified in the transition transcriptome and databases.
Results: Our analysis was based on 1107 ESTs from a transition cDNA library of P. brasiliensis. A total of 639 consensus
sequences were assembled. Genes of primary metabolism, energy, protein synthesis and fate, cellular transport,
biogenesis of cellular components were represented in the transition cDNA library. A considerable number of genes
(7.51%) had not been previously reported for P. brasiliensis in public databases. Gene expression analysis using in silico
EST subtraction revealed that numerous genes were more expressed during the transition phase when compared to the
mycelial ESTs [1]. Classes of differentially expressed sequences were selected for further analysis including: genes related
to the synthesis/remodeling of the cell wall/membrane. Thirty four genes from this family were induced. Ten genes
related to signal transduction were increased. Twelve genes encoding putative virulence factors manifested increased
expression. The in silico approach was validated by northern blot and semi-quantitative RT-PCR.
Conclusion: The developmental program of P. brasiliensis is characterized by significant differential positive modulation
of the cell wall/membrane related transcripts, and signal transduction proteins, suggesting the related processes
important contributors to dimorphism. Also, putative virulence factors are more expressed in the transition process
suggesting adaptation to the host of the yeast incoming parasitic phase. Those genes provide ideal candidates for further
studies directed at understanding fungal morphogenesis and its regulation.
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BASTOS, Karinne P.; BAILÃO, Alexandre M.; BORGES, Clayton L.; FARIA, Fabricia P.; FELIPE, Maria S. S.; SILVA, Mirelle G.; MARTINS, Wellington S.; Rogério B; PEREIRA, Maristela; SOARES, Célia M. A. The transcriptome analysis of early morphogenesis in Paracoccidioides brasiliensis mycelium reveals novel and induced genes potentially associated to the dimorphic process. BMC Microbiology, London, v. 7, p. 29, Apr. 2007.