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Differential expression of an hsp70 gene during transition from the mycelial to the infective yeast form of the human pathogenic fungus Paracoccidioides brasiliensis
Author(s) -
Da Silva Silvana Petrofeza,
BorgesWalmsley Maria Ines,
Pereira Ildinete Silva,
Soares Célia Maria de Almeida,
Walmsley Adrian Robert,
Felipe Maria Sueli Soares
Publication year - 1999
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1999.01236.x
Subject(s) - biology , paracoccidioides brasiliensis , yeast , gene , intron , gene expression , rna splicing , microbiology and biotechnology , paracoccidioides , hsp70 , saccharomyces cerevisiae , heat shock protein , heat shock , genetics , rna
We have isolated and characterized cDNA and genomic clones that encode a 70 kDa heat shock protein (Hsp70) from the dimorphic human pathogenic fungus Paracoccidioides brasiliensis . The gene encodes a 649‐amino‐acid protein showing high identity with other members of the hsp70 gene family. The hsp70 gene is induced during both heat shock of yeast cells at 42°C and the mycelial to yeast transition. A differential expression of this gene can be observed between mycelial and yeast forms, with a much higher level of expression in the yeast. We found two introns of 178 and 72 nucleotides in the P. brasiliensis hsp70 gene. Splicing of these introns is regulated during the heat shock process and possibly during infection. In order to analyse the differential accumulation of unspliced mRNA following cellular differentiation and/or heat shock, reverse transcriptase–polymerase chain reaction (RT–PCR) experiments were carried out. The temperature‐induced mycelial to yeast transition results in the transient accumulation of unspliced hsp70 mRNA transcripts. Yeast cells, after adaptation at 36°C, seem to be more proficient at splicing, at least with respect to hsp70 mRNA because, during a severe heat shock (42°C), the unspliced form of this mRNA does not accumulate. The mycelial to yeast differentiation will have the adaptational effect of increasing the resistance of the organism to environmental stress, which may be necessary for parasite survival in the mammalian host.