Suppression subtractive analyses revealed genes down-regulated in the pala1 mutant strain of Aspergillus nidulans grown in acid pH

FREITAS JS; SILVA EM; LEAL J; SQUINA FM; GRAS DE; SILVEIRA HC; MARTINEZ-ROSSI NM; ROSSI A

Salvador

Conferencia; XXXVI Annual Meeting of the SBBq and 10th IUBMB Conference Infectious Diseases: Biochemistry of Parasites, Vectors and Hosts; 2007

Sociedade Brasileira de Bioquímica e Biologia Molecular

The pH regulation in A. nidulans is mediated by at least seven genes: six members of the activating signaling cascade (pal A, B, C, F, H and I) and pacC, which codes for the transcription factor PacC. The proteolized form of PacC, which occurs by the action of the pal genes at alkaline pH, activates the transcription of alkaline -expressed genes and represses the transcription of acid-expressed genes. Contemplating one more step towards the understanding of extracellular pH signaling in fungi, we employed suppression subtractive hybridizations of cDNA, using the strains biA1 and palA1 biA1 respectively as tester and driver, both strains grown in low-Pi, pH 5.0. Out of a total of 600 cDNA clones analyzed by dot blot macro-array, 200 were confirmed as differentially expressed in the biA1 strain, which represented 45 different unigenes. Northern blots confirmed differential expression of three heat shock proteins, HSPs 30, 70, and 90, down-regulated in the mutant palA1 biA1. Our data contributes to recognize molecular mechanisms involved in pH signaling as also to understand the functionality of gene palA1.