The RGS domain-containing fission yeast protein, Rgs1p, regulates pheromone signalling and is required for mating.
BACKGROUND
When nutritionally starved, the fission yeast Schizosaccharomyces pombe enters a cell differentiation process which leads to mating and meiosis. The Ste11 protein is a key regulator of this differentiation pathway, activating the transcription of mating and meiotic genes upon starvation.


RESULTS
Here, we describe rgs1, a member of the Regulator of G-protein Signalling (RGS) family, as a novel Ste11 target gene. rgs1 expression requires both an Ste11-mediated nitrogen starvation signal and the pheromone-induced activation of the Byr2/Byr1/Spk1 MAPK pathway. We show that rgs1 deletion results in a sensitivity to pheromone and in a mating defect. Deltargs1 cells initiate the mating pathway normally, undergoing sexual agglutination and G1 arrest, while inducing pheromone-dependent transcription, but then fail to fuse with a mating partner while elongating abnormal conjugation tubes. Endogenous Rgs1 tagged with GFP localizes to the nucleus and cytoplasm, and this localization pattern is not altered during pheromone treatment. Importantly, Rgs1 function requires its C-terminal RGS domain, as well as a central DEP domain and a novel homology domain present in its N-terminal region (Fungal-DR domain).


CONCLUSIONS
These results demonstrate that rgs1 expression requires nutritional starvation and pheromone signalling. Rgs1 negatively regulates pheromone signalling during mating, acting in a negative feedback loop that is essential for the mating process.
Pereira
P S
PS
Imperial Cancer Research Fund, Gene Regulation Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK.
Jones
N C
NC
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D003227:Conjugation, Genetic / Q000502:physiology; D017931:DNA Primers / Q000737:chemistry; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000502:physiology; D049452:Green Fluorescent Proteins; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D010675:Pheromones / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D020710:RGS Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012568:Schizosaccharomyces / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology
D017931:DNA Primers; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008164:Luminescent Proteins; C089516:Mating Factor, S pombe; D010455:Peptides; D010675:Pheromones; D020710:RGS Proteins; C080831:RGS1 protein, human; D012333:RNA, Messenger; C489854:Rgs1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; C490320:mfm1 protein, S pombe; C071596:ste11 protein, S pombe; D049452:Green Fluorescent Proteins; D020929:Mitogen-Activated Protein Kinase Kinases