Transcriptional profiling of Neurospora crassa mak-2 reveals that mitogen-activated protein kinase MAK-2 participates in the phosphate signaling pathway

GRAS DE; PERSINOTI GF; PERES NT; TAHIRA AC; REIS EM; PRADE RA; ROSSI A

FUNGAL GENETICS AND BIOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Madison; Año: 2013

1087-1845

The filamentous fungus Neurospora crassa is an excellent modelsystem for examining molecular responses to ambient signals in eukaryoticmicroorganisms. Inorganic phosphate is an essential growth-limitingnutrient in nature and is crucial for the synthesis of nucleic acids andthe flow of genetic information. Numerous ambient signals activate therecruitment of mitogen-activated protein kinase (MAPK) cascades. Thus, toidentify genes involved in metabolic responses to exogenous phosphatesensing and the functioning of an MAPK, MAK-2, we performed microarrayexperiments using a mak-2 knockout strain (Δmak-2) grown under phosphateshortageconditions by comparing its transcription profile to that of acontrol strain grown in low- and high-phosphate cultures. Theseexperiments revealed 912 unique differentially expressed genes involvedin a number of physiological processes related to phosphate transport,metabolism, and regulation as well as posttranslational modification ofproteins, and MAPK signaling pathways. Quantitative real-time-PCR geneexpression analysis using independent RNA samples of 10 arbitrarilychosen genes validated our microarray results. A high Pearson correlationbetween microarray and quantitative real-time-PCR data was observed. Theanalysis of these differentially expressed genes in the Δmak-2 strainprovide evidence that the mak-2 gene participates of the hierarchicalphosphate-signaling pathway in N. crassa in addition to its independentinvolvement in other metabolic routes such as the isoprenylation pathway,thus revealing novel aspects of the N. crassa phosphorus-sensing network.