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

Author(s)

Gras, Diana E. ; Persinoti, Gabriela F. ; Peres, Nalu T. A. ; Martinez-Rossi, Nilce M. ; Tahira, Ana C. ; Reis, Eduardo M. ; Prade, Rolf A. ; Rossi, Antonio

• Document type: Journal article
• Source: Fungal Genetics and Biology; v. 60, p. 10-pg., 2013-11-01.

Abstract

The filamentous fungus Neurospora crassa is an excellent model system for examining molecular responses to ambient signals in eukaryotic microorganisms. Inorganic phosphate (Pi) is an essential growth-limiting nutrient in nature and is crucial for the synthesis of nucleic acids and the flow of genetic information. The genetic and molecular mechanisms controlling the response to Pi starvation in N. crassa include at least four genes (nuc-2, preg, pogv, and nuc-1), which are involved in a hierarchical regulatory activation network. In a previous work, we identified a number of genes modulated by NUC-2 protein, including the mak-2 gene, which codes for a mitogen-activated protein kinase (MAPK), suggesting its participation in the phosphate signaling pathway. Thus, to identify other genes involved in metabolic responses to exogenous phosphate sensing and the functioning of the MAPK MAK-2, we performed microarray experiments using a mak-2 knockout strain (Delta mak-2) grown under phosphate-shortage conditions by comparing its transcription profile to that of a control strain grown in low- and high-phosphate cultures. These experiments revealed 912 unique differentially expressed genes involved in a number of physiological processes related to phosphate transport, metabolism, and regulation as well as post-translational modification of proteins, and MAPK signaling pathways. Quantitative Real-time PCR gene expression analysis of 18 selected genes, using independent RNA samples, validated our microarray results. A high Pearson correlation between microarray and quantitative Real-time PCR data was observed. The analysis of these differentially expressed genes in the Delta mak-2 strain provide evidence that the mak-2 gene participates in the hierarchical phosphate-signaling pathway in N. crassa in addition to its involvement in other metabolic routes such as the isoprenylation pathway, thus revealing novel aspects of the N. crassa phosphorus-sensing network. (C) 2013 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 08/58634-7 - Functional and comparative genomics in fungi
• Grantee: Nilce Maria Martinez-Rossi
• Support Opportunities: Research Projects - Thematic Grants