Identification of differentially expressed genes in the nuc-2 mutant strain of Neurospora crassa

GRAS DE; SILVEIRA HC; MARTINEZ-ROSSI NM; ROSSI A

Viena

Conferencia; 8th European Conference on Fungal Genetics; 2006

Federation of European Microbiological Societies

The filamentous mould Neurospora crassa synthesizes a number of phosphate (Pi)-repressible phosphatases and permeases that have the function of making more Pi available to the cell, i.e., these enzymes are synthesized and secreted in response to the signaling of phosphorus starvation. The genetic and molecular mechanisms controlling this response in N. crassa include four regulatory genes, nuc-2, preg, pgov, and nuc-1, involved in a hierarchical relationship. Nuc-1 is a positive wide domain transcription factor. Nuc-2 senses the availability of Pi and transmits the metabolic signal downstream the regulatory pathway. Also, Nuc-2 is an ankyrin repeat protein, a class of proteins that regulate, for example, important biological functions of the cell cycle and of the cytoskeleton organization. Here, we describe genes which are differentially expressed in response to nuc-2 mutation, by employing the suppression subtractive hybridization (SSH) approach. The driver and tester cDNAs were obtained from mycelium of the St.L.74A and nuc-2 (FGSC# 1996) strains of N. crassa, respectively. Out of a total of 550 cDNA clones analyzed by dot-blot macroarrays, we confirmed 50 clones differentially expressed in the nuc-2 mutant strain, representing 40 different genes. Based on BLAST homology, the clones selected from these libraries are largely of fungal origin. The hypothetical proteins represent 52% of the total, and the putative proteins identified are involved in metabolism, cell signaling, and cell fate. These studies provide data that are useful for identifying the role of gene nuc-2 in the expression of proteins other than those involved in the acquisition of Pi from the ambient.