Emiliana M Silva

Publications (3)7.92 Total impact

• Source

  Available from: Mário S Palma

  Article: Transcription of the Hsp30, Hsp70, and Hsp90 heat shock protein genes is modulated by the PalA protein in response to acid pH-sensing in the fungus Aspergillus nidulans.

  Janaína S Freitas, Emiliana M Silva, Juliana Leal, Diana E Gras, Nilce M Martinez-Rossi, Lucilene Delazari Dos Santos, Mario S Palma, Antonio Rossi
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  ABSTRACT: Heat shock proteins are molecular chaperones linked to a myriad of physiological functions in both prokaryotes and eukaryotes. In this study, we show that the Aspergillus nidulans hsp30 (ANID_03555.1), hsp70 (ANID_05129.1), and hsp90 (ANID_08269.1) genes are preferentially expressed in an acidic milieu, whose expression is dependent on the palA (+) background under optimal temperature for fungal growth. Heat shock induction of these three hsp genes showed different patterns in response to extracellular pH changes in the palA(+) background. However, their accumulation upon heating for 2 h was almost unaffected by ambient pH changes in the palA (-) background. The PalA protein is a member of a conserved signaling cascade that is involved in the pH-mediated regulation of gene expression. Moreover, we identified several genes whose expression at pH 5.0 is also dependent on the palA (+) background. These results reveal novel aspects of the heat- and pH-sensing networks of A. nidulans.
  Cell Stress and Chaperones 05/2011; 16(5):565-72. · 3.01 Impact Factor
• Article: A splice variant of the Neurospora crassa hex-1 transcript, which encodes the major protein of the Woronin body, is modulated by extracellular phosphate and pH changes.

  Juliana Leal, Fábio M Squina, Janaína S Freitas, Emiliana M Silva, Carlos J Ono, Nilce M Martinez-Rossi, Antonio Rossi
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  ABSTRACT: The Woronin body, a septal pore-associated organelle specific to filamentous ascomycetes, is crucial for preventing cytoplasmic bleeding after hyphal injury. In this study, we show that T1hex-1 transcript and a variant splicing T2hex-1 transcript are up-regulated at alkaline pH. We also show that both hex-1 transcripts are overexpressed in the preg(c), nuc-1(RIP), and pacC(ko) mutant strains of Neurospora crassa grown under conditions of phosphate shortage at alkaline pH, suggesting that hex-1 transcription may be coregulated by these genes. In addition, we present evidence that N. crassa PacC also has metabolic functions at acidic pH.
  FEBS letters 01/2009; 583(1):180-4. · 3.54 Impact Factor
• Article: Identification of genes differentially expressed in a strain of the mold Aspergillus nidulans carrying a loss-of-function mutation in the palA gene.

  Emiliana M Silva, Janaína S Freitas, Diana E Gras, Fábio M Squina, Juliana Leal, Henrique C S Silveira, Nilce M Martinez-Rossi, Antonio Rossi
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  ABSTRACT: To identify genes differentially expressed in a strain of the mold Aspergillus nidulans carrying a loss-of-function mutation in palA, a gene in the pH-responsive signal transduction pathway, suppression subtractive hybridization was performed between RNA isolated from the biA1 and biA1 palA1 strains grown under limiting inorganic phosphate at pH 5.0. We have identified several genes upregulated in the biA1 palA1 mutant strain that play important roles in mitotic fidelity, stress responses, enzyme secretion, signal transduction mechanisms, development, genome stability, phosphate sensing, and transcriptional regulation among others. The upregulation of eight of these transcripts was also validated by Northern blot. Moreover, we show that a loss of function mutation in the palA gene drastically reduced the neutral sugar content of the acid phosphatase PacA secreted by the fungus A. nidulans grown at pH 5.0 compared with a control strain.
  Canadian Journal of Microbiology 11/2008; 54(10):803-11. · 1.36 Impact Factor