Project description:Abstract BACKGROUND: Mating-type loci in yeasts and ascomycotan filamentous fungi (Pezizomycotina) encode master transcriptional factors that play a critical role in sexual development. Genome-wide analyses of mating-type-specification circuits and mating-type target genes are available in Saccharomyces cerevisiae and Schizosaccharomyces pombe; however, no such analyses have been performed in heterothallic (self-incompatible) Pezizomycotina. The heterothallic fungus Podospora anserina serves as a model for understanding the basic features of mating-type control. Its mat+ and mat- mating types are determined by dissimilar allelic sequences. The mat- sequence contains three genes, designated FMR1, SMR1 and SMR2, while the mat+ sequence contains one gene, FPR1. FMR1 and FPR1 are the major regulators of fertilization, and this study presents a genome-wide view of their target genes and analyzes their target gene regulation. METHODOLOGY/PRINCIPAL FINDINGS: The transcriptomic profiles of the mat+ and mat- strains revealed 157 differentially transcribed genes, and transcriptomic analysis of fmr1(-) and fpr1(-) mutant strains was used to determine the regulatory actions exerted by FMR1 and FPR1 on these differentially transcribed genes. All possible combinations of transcription repression and/or activation by FMR1 and/or FPR1 were observed. Furthermore, 10 additional mating-type target genes were identified that were up- or down-regulated to the same level in mat+ and mat- strains. Of the 167 genes identified, 32 genes were selected for deletion, which resulted in the identification of two genes essential for the sexual cycle. Interspecies comparisons of mating-type target genes revealed significant numbers of orthologous pairs, although transcriptional profiles were not conserved between species. CONCLUSIONS/SIGNIFICANCE: This study represents the first comprehensive genome-wide analysis of mating-type direct and indirect target genes in a heterothallic filamentous fungus. Mating-type transcription factors have many more target genes than are found in yeasts and exert a much greater diversity of regulatory actions on target genes, most of which are not directly related to mating.
Project description:Neurospora tetrasperma is a pseudohomothallic filamentous ascomycete with a large (~ 7 Mbp) region of suppressed recombination surrounding its mating-type (mat) locus. The suppressed recombination has lead to sequence divergence between the two mating-type chromosomes of wild-type heterokaryotic strains, while the remaining genome is largely homoallelic. In this study, we use microarray technology to manifest expression divergence linked to mating type in N. tetrasperma. N. tetrasperma and N. crassa, were grown on agar regimes inducing sexual growth (Synthetic Crossing medium) and vegetative growth (Vogel's Medium), respectively.
Project description:Abstract BACKGROUND: Mating-type loci in yeasts and ascomycotan filamentous fungi (Pezizomycotina) encode master transcriptional factors that play a critical role in sexual development. Genome-wide analyses of mating-type-specification circuits and mating-type target genes are available in Saccharomyces cerevisiae and Schizosaccharomyces pombe; however, no such analyses have been performed in heterothallic (self-incompatible) Pezizomycotina. The heterothallic fungus Podospora anserina serves as a model for understanding the basic features of mating-type control. Its mat+ and mat- mating types are determined by dissimilar allelic sequences. The mat- sequence contains three genes, designated FMR1, SMR1 and SMR2, while the mat+ sequence contains one gene, FPR1. FMR1 and FPR1 are the major regulators of fertilization, and this study presents a genome-wide view of their target genes and analyzes their target gene regulation. METHODOLOGY/PRINCIPAL FINDINGS: The transcriptomic profiles of the mat+ and mat- strains revealed 157 differentially transcribed genes, and transcriptomic analysis of fmr1(-) and fpr1(-) mutant strains was used to determine the regulatory actions exerted by FMR1 and FPR1 on these differentially transcribed genes. All possible combinations of transcription repression and/or activation by FMR1 and/or FPR1 were observed. Furthermore, 10 additional mating-type target genes were identified that were up- or down-regulated to the same level in mat+ and mat- strains. Of the 167 genes identified, 32 genes were selected for deletion, which resulted in the identification of two genes essential for the sexual cycle. Interspecies comparisons of mating-type target genes revealed significant numbers of orthologous pairs, although transcriptional profiles were not conserved between species. CONCLUSIONS/SIGNIFICANCE: This study represents the first comprehensive genome-wide analysis of mating-type direct and indirect target genes in a heterothallic filamentous fungus. Mating-type transcription factors have many more target genes than are found in yeasts and exert a much greater diversity of regulatory actions on target genes, most of which are not directly related to mating. With GPL10116 : 4 conditions each with four biological replicates :mat+, mat-, fpr1-, fmr1-; common reference is a pool of four conditions M48h, M96h, C48h and C96h ; Conditions are labelled in Cy3 and the common reference in Cy5