title: Evidence for a functional link between Dd-STATa and Dd-PIAS, a Dictyostelium PIAS homologue.
abstract: Several mammalian protein families inhibit the activity of signal transducer and activator of transcription (STAT) proteins. The protein inhibitor of activated STAT (PIAS) was initially identified through its ability to interact with human STAT proteins. We isolated a gene (pisA) encoding a Dictyostelium orthologue of PIAS, Dd-PIAS, which possesses almost all the representative motifs and domains of mammalian PIAS proteins. A Dd-PIAS null mutant strain displays a normal terminal morphology but with accelerated development once cells are aggregated. In contrast, Dd-PIAS overexpressor strains demonstrate delayed aggregation, almost no slug phototaxis, impaired slug motility, and a prolonged slug migration period. This strain is a near phenocopy of the Dd-STATa null mutant, although it eventually forms a fruiting body, albeit inefficiently. The expression of several Dd-STATa-activated genes is upregulated in the Dd-PIAS null mutant and there is ectopic expression of pstAB makers. The concentration of a PIAS-green fluorescent protein (GFP) fusion protein, expressed under the PIAS promoter, is greatest in the pstO cells and gradually decreases with proximity to the tip of the slug and culminant: a pattern diametrically opposite to that of Dd-STATa. Our results suggest a functional interrelationship between Dd-PIAS and Dd-STATa that influences gene expression and development.
authors.affiliation: Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, Japan. tkawata@bio.sci.toho-u.ac.jp
authors.forename: Takefumi
authors.initials: T
authors.lastname: Kawata
authors.forename: Tatsunori
authors.initials: T
authors.lastname: Hirano
authors.forename: Shun
authors.initials: S
authors.lastname: Ogasawara
authors.forename: Ryota
authors.initials: R
authors.lastname: Aoshima
authors.forename: Ayako
authors.initials: A
authors.lastname: Yachi
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004023:Dictyostelium / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017125:Genes, Protozoan; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D050828:Protein Inhibitors of Activated STAT / Q000235:genetics* / Q000378:metabolism; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D050791:STAT Transcription Factors / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D050828:Protein Inhibitors of Activated STAT; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D050791:STAT Transcription Factors; C426583:STATa protein, Dictyostelium; D049452:Green Fluorescent Proteins