The fission yeast GATA factor, Gaf1, modulates sexual development via direct down-regulation of ste11+ expression in response to nitrogen starvation.
Gaf1 is the first GATA family zinc-finger transcription factor identified in Schizosaccharomyces pombe. Here, we report that Gaf1 functions as a negatively acting transcription factor of ste11(+), delaying the entrance of cells exposed to transient nitrogen starvation into the meiotic cycle. gaf1Δ strains exhibited accelerated G(1)-arrest upon nitrogen starvation. Moreover, gaf1Δ mutation caused increased mating and sporulation frequency under both nitrogen-starved and unstarved conditions, while overexpression of gaf1(+) led to a significant impairment of sporulation. By microarray analysis, we found that approximately 63% (116 genes) of the 183 genes up-regulated in unstarved gaf1Δ cells were nitrogen starvation-responsive genes, and furthermore that 25 genes among the genes up-regulated by gaf1Δ mutation are Ste11 targets (e.g., gpa1(+), ste4(+), spk1(+), ste11(+), and mei2(+)). The phenotype caused by gaf1Δ mutation was masked by ste11Δ mutation, indicating that ste11(+) is epistatic to gaf1(+) with respect to sporulation efficiency, and accordingly that gaf1(+) functions upstream of ste11(+) in the signaling pathway governing sexual development. gaf1Δ strains showed accelerated ste11(+) expression under nitrogen starvation and increased ste11(+) expression even under normal conditions. Electrophoretic mobility shift assay analysis demonstrated that Gaf1 specifically binds to the canonical GATA motif (5'-HGATAR-3') spanning from -371 to -366 in ste11(+) promoter. Consequently, Gaf1 provides the prime example for negative regulation of ste11(+) transcription through direct binding to a cis-acting motif of its promoter.
Department of Microbiology and Molecular Biology, Chungnam National University, Daejeon, Korea.
Lila
L
Kim
Kwang-Lae
KL
Hoe
Yeong Man
YM
Yu
Ji-Hyun
JH
Yeon
Pil Jae
PJ
Maeng
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D015536:Down-Regulation; D004843:Epistasis, Genetic; D059585:G1 Phase Cell Cycle Checkpoints / Q000235:genetics; D050980:GATA Transcription Factors / Q000378:metabolism*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D009154:Mutation; D009584:Nitrogen / Q000378:metabolism*; D059372:Nucleotide Motifs; D010675:Pheromones / Q000235:genetics; D011401:Promoter Regions, Genetic; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism*; D013172:Spores, Fungal / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*
D050980:GATA Transcription Factors; C114485:Gaf1 protein, S pombe; D010675:Pheromones; D029702:Schizosaccharomyces pombe Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C071596:ste11 protein, S pombe; D009584:Nitrogen