title: Psr1, a nuclear localized protein that regulates phosphorus metabolism in Chlamydomonas.
abstract: Understanding the ways in which phosphorus metabolism is regulated in photosynthetic eukaryotes is critical for optimizing crop productivity and managing aquatic ecosystems in which phosphorus can be a major source of pollution. Here we describe a gene encoding a regulator of phosphorus metabolism, designated Psr1 (phosphorus starvation response), from a photosynthetic eukaryote. The Psr1 protein is critical for acclimation of the unicellular green alga Chlamydomonas reinhardtii to phosphorus starvation. The N-terminal half of Psr1 contains a region similar to myb DNA-binding domains and the C-terminal half possesses glutamine-rich sequences characteristic of transcriptional activators. The level of Psr1 increases at least 10-fold upon phosphate starvation, and immunocytochemical studies demonstrate that this protein is nuclear-localized under both nutrient-replete and phosphorus-starvation conditions. Finally, Psr1 and angiosperm proteins have domains that are similar, suggesting a possible role for Psr1 homologs in the control of phosphorus metabolism in vascular plants. With the identification of regulators such as Psr1 it may become possible to engineer photosynthetic organisms for more efficient utilization of phosphorus and to establish better practices for the management of agricultural lands and natural ecosystems.
authors.affiliation: Carnegie Institution of Washington, 260 Panama Street, Stanford, CA 94305, USA.
authors.forename: D D
authors.initials: DD
authors.lastname: Wykoff
authors.forename: A R
authors.initials: AR
authors.lastname: Grossman
authors.forename: D P
authors.initials: DP
authors.lastname: Weeks
authors.forename: H
authors.initials: H
authors.lastname: Usuda
authors.forename: K
authors.initials: K
authors.lastname: Shimogawara
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D002451:Cell Compartmentation; D016825:Chlamydomonas reinhardtii / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005057:Eukaryotic Cells; D015723:Gene Library; D017343:Genes, Plant; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D010758:Phosphorus / Q000172:deficiency / Q000378:metabolism*; D010788:Photosynthesis; D010940:Plant Proteins; D010944:Plants / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; C403075:Psr1 protein, Chlamydomonas; D010758:Phosphorus