title: Dictyostelium TRFA homologous to yeast Ssn6 is required for normal growth and early development.
abstract: The TPR (tetratricopeptide repeat) family became widespread during evolution, having been found from bacteria to mammals. By means of restriction enzyme-mediated integration, we have identified a Dictyostelium gene (trfA) highly homologous to a Saccharomyces cerevisiae gene encoding a TPR protein, Ssn6 (Cyc8), which functions as a global transcriptional repressor for diverse genes. The deduced amino acid sequence of the Dictyostelium gene product, TRFA, contains 10 consecutive TPR units as well as Gln repeats, Asn repeats, and a region rich in Glu, Lys, Ser, and Thr. The sequences of some of the 10 TPR units in TRFA are more than 70% identical to the corresponding units in Ssn6. The trfA- cells produced smooth plaques on a bacterial lawn and failed to aggregate normally when starved on a plain agar plate. Individual trfA- cells also failed to correctly respond to cAMP, although the adenylyl cyclase of trfA- cells was expressed upon starvation and activated by stimulation with cAMP as in the wild-type cells. When cultured in a rich medium in suspension, they grew more slowly and stopped growing at a lower density than the wild-type cells. Furthermore, they divided into cells of various sizes and tended to be much smaller than the wild-type cells. These pleiotropic defects of the trfA- cells suggest the possibility that Dictyostelium TRFA may regulate the transcription of diverse genes required for normal growth and early development.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Saito
authors.forename: T
authors.initials: T
authors.lastname: Kon
authors.forename: A
authors.initials: A
authors.lastname: Nagasaki
authors.forename: H
authors.initials: H
authors.lastname: Adachi
authors.forename: K
authors.initials: K
authors.lastname: Sutoh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology; D000242:Cyclic AMP / Q000494:pharmacology; D004261:DNA Replication; D004268:DNA-Binding Proteins; D004023:Dictyostelium / Q000235:genetics / Q000254:growth & development*; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010641:Phenotype; D015800:Protozoan Proteins; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: C065455:CYC8 protein, S cerevisiae; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D015800:Protozoan Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C114739:TrfA protein, Dictyostelium; D000242:Cyclic AMP