Supression subtractive hybridization analyses identified gene up-regulated in the pala1 mutant strain of Aspergillus nidulans.

SILVA EM; FREITAS JS; GRAS DE; SILVEIRA HC; LEAL J; SQUINA FM; 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 of gene expression in A. nidulans is mediated by gene pacC, which encodes a Zn-finger transcription factor. The six pal genes (palA, B, C, F, H, and I) are members of a signaling cascade, which promotes the proteolytic activation of PacC in alkaline environment. The PalA protein interacts with the YPXL/I motifs in PacC, what is required for the action of PalB, a calpain-like protease. This model implies that loss-of-function mutation in any of the six pal genes shall lead to a wild-type acidic growth phenotype regardless on the ambient pH, what was not observed in the palA1 mutant strain. Employing suppression subtractive hybridization, we identified genes up-regulated in the palA1 mutant strain of A. nidulans grown in low-Pi medium, pH 5.0, whose expression was confirmed by Northern blotting, an unexpected result since palA1 mutant should have an wild-type behavior at pH 5.0. This result shows a derangement in the gene expression profile at pH 5.0, indicating that palA gene is functional at acidic pH and, therefore, the palA1 mutation did not cause an acidic-mimicking phenotype