New features over the expression of Neurospora crassa genes in response to extracellular phosphate levels and pH

SQUINA FM; LEAL J; GRAS DE; FREITAS JS; SILVA EM; MARTINEZ-ROSSI NM; ROSSI A

Asilomar

Encuentro; The Neurospora 2008 meeting at Asilomar; 2008

Genetics Society of America

Microorganisms have evolved complex signal transduction networks that enable them to adapt effectively in response to environmental changes in nutrients and extracellular pH. The phosphorus (Pi) acquisition system in Neurospora crassa includes four regulatory genes: nuc-2, preg, pgov and nuc-1. In response to signals of Pi starvation, NUC-2 inhibits the functioning of the complex PREG-PGOV allowing the translocation of transcription regulator NUC-1 into the nucleus and expression of Pi-repressible phosphatases. In an attempt to further understand the molecular responses to exogenous Pi sensing, six subtractive cDNA libraries were constructed to identify genes differentially expressed in the nuc-1RIP and nuc-2A mutant strains of N. crassa grown in low Pi, at acidic and alkaline pH. We identified genes involved in diverse cellular processes such as cellular transport, cellular metabolism, protein biosynthesis, regulation of transcription, development and signal transduction, revealing novel molecular aspects of the functioning of nuc-1 and nuc-2 genes. We also found that transcription of two heat shock protein genes is affected by growth pH while another one is overexpressed when nuc-1 gene is non functional.