TY - JOUR
T1 - Functional characterization of the Aspergillus fumigatus PHO80 homologue
AU - de Gouvêa, Paula Fagundes
AU - Soriani, Frederico Marianetti
AU - Malavazi, Iran
AU - Savoldi, Marcela
AU - Goldman, Maria Helena de Souza
AU - Loss, Omar
AU - Bignell, Elaine
AU - da Silva Ferreira, Márcia Eliana
AU - Goldman, Gustavo Henrique
PY - 2008/7
Y1 - 2008/7
N2 - Phosphate is an ion that is essential for fungal growth. The systems for inorganic phosphate (P i) acquisition in eukaryotic cells (PHO) have been characterized as a low-affinity (that assures a supply of P i at normal or high external P i concentrations) and a high-affinity (activated in response to P i starvation). Here, as an initial step to understand the PHO pathway in Aspergillus fumigatus, we characterized the PHO80 homologue, PhoB PHO80. We show that the ΔphoB PHO80 mutant has a polar growth defect (i.e., a delayed germ tube emergence) and, by phenotypic and phosphate uptake analyses, establish a link between PhoB PHO80, calcineurin and calcium metabolism. Microarray hybridizations carried out with RNA obtained from wild-type and ΔphoB PHO80 mutant cells identify Afu4g03610 (phoD PHO84), Afu7g06350 (phoE PHO89), Afu4g06020 (phoC PHO81), and Afu2g09040 (vacuolar transporter Vtc4) as more expressed both in the ΔphoB PHO80 mutant background and under phosphate-limiting conditions of 0.1 mM P i. Epifluorescence microscopy revealed accumulation of poly-phosphate in ΔphoB PHO80 vacuoles, which was independent of extracellular phosphate concentration. Surprisingly, a phoD PHO84 deletion mutant is indistinguishable phenotypically from the corresponding wild-type strain. mRNA analyses suggest that protein kinase A absence supports the expression of PHO genes in A. fumigatus. Furthermore, ΔphoB PHO80 and ΔphoD PHO84 mutant are fully virulent in a murine low dose model for invasive aspergillosis. © 2008 Elsevier Inc. All rights reserved.
AB - Phosphate is an ion that is essential for fungal growth. The systems for inorganic phosphate (P i) acquisition in eukaryotic cells (PHO) have been characterized as a low-affinity (that assures a supply of P i at normal or high external P i concentrations) and a high-affinity (activated in response to P i starvation). Here, as an initial step to understand the PHO pathway in Aspergillus fumigatus, we characterized the PHO80 homologue, PhoB PHO80. We show that the ΔphoB PHO80 mutant has a polar growth defect (i.e., a delayed germ tube emergence) and, by phenotypic and phosphate uptake analyses, establish a link between PhoB PHO80, calcineurin and calcium metabolism. Microarray hybridizations carried out with RNA obtained from wild-type and ΔphoB PHO80 mutant cells identify Afu4g03610 (phoD PHO84), Afu7g06350 (phoE PHO89), Afu4g06020 (phoC PHO81), and Afu2g09040 (vacuolar transporter Vtc4) as more expressed both in the ΔphoB PHO80 mutant background and under phosphate-limiting conditions of 0.1 mM P i. Epifluorescence microscopy revealed accumulation of poly-phosphate in ΔphoB PHO80 vacuoles, which was independent of extracellular phosphate concentration. Surprisingly, a phoD PHO84 deletion mutant is indistinguishable phenotypically from the corresponding wild-type strain. mRNA analyses suggest that protein kinase A absence supports the expression of PHO genes in A. fumigatus. Furthermore, ΔphoB PHO80 and ΔphoD PHO84 mutant are fully virulent in a murine low dose model for invasive aspergillosis. © 2008 Elsevier Inc. All rights reserved.
KW - Aspergillus fumigatus
KW - Inorganic phosphate acquisition
KW - PHO80
KW - Protein kinase A
U2 - 10.1016/j.fgb.2008.04.001
DO - 10.1016/j.fgb.2008.04.001
M3 - Article
C2 - 18538268
SN - 1087-1845
VL - 45
SP - 1135
EP - 1146
JO - Fungal Genetics and Biology
JF - Fungal Genetics and Biology
IS - 7
ER -