title: An F-Box/WD40 repeat-containing protein important for Dictyostelium cell-type proportioning, slug behaviour, and culmination.
abstract: FbxA is a novel member of a family of proteins that contain an F-box and WD40 repeats and that target specific proteins for degradation via proteasomes. In fruiting bodies formed from cells where the fbxA gene is disrupted (fbxA(-) cells), the spore mass fails to fully ascend the stalk. In addition, fbxA(-) slugs continue to migrate under environmental conditions where the parental strain immediately forms fruiting bodies. Consistent with this latter behaviour, the development of fbxA(-) cells is hypersensitive to ammonia, the signaling molecule that regulates the transition from the slug stage to terminal differentiation. The slug comprises an anterior prestalk region and a posterior prespore region and the fbxA mRNA is highly enriched in the prestalk cells. The prestalk zone of the slug is further subdivided into an anterior pstA region and a posterior pstO region. In fbxA(-) slugs the pstO region is reduced in size and the prespore region is proportionately expanded. Our results indicate that FbxA is part of a regulatory pathway that controls cell fate decisions and spatial patterning via regulated protein degradation.
authors.affiliation: Department of Biology, Allegheny College, Meadville, Pennsylvania 16335, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Nelson
authors.forename: A
authors.initials: A
authors.lastname: Clark
authors.forename: T
authors.initials: T
authors.lastname: Abe
authors.forename: A
authors.initials: A
authors.lastname: Nomura
authors.forename: N
authors.initials: N
authors.lastname: Yadava
authors.forename: C J
authors.initials: CJ
authors.lastname: Funair
authors.forename: K A
authors.initials: KA
authors.lastname: Jermyn
authors.forename: S
authors.initials: S
authors.lastname: Mohanty
authors.forename: R A
authors.initials: RA
authors.lastname: Firtel
authors.forename: J G
authors.initials: JG
authors.lastname: Williams
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000643:Ammonium Chloride / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D004023:Dictyostelium / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D044783:F-Box Proteins; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010641:Phenotype; D015800:Protozoan Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D044783:F-Box Proteins; C412452:FbxA protein, Dictyostelium; D015800:Protozoan Proteins; D000643:Ammonium Chloride