title: Trishanku, a novel regulator of cell-type stability and morphogenesis in Dictyostelium discoideum.
abstract: We have identified a novel gene, trishanku (triA), by random insertional mutagenesis of Dictyostelium discoideum. TriA is a Broad complex Tramtrack bric-a-brac domain-containing protein that is expressed strongly during the late G2 phase of cell cycle and in presumptive spore (prespore (psp)) cells. Disrupting triA destabilizes cell fate and reduces aggregate size; the fruiting body has a thick stalk, a lowered spore: stalk ratio, a sub-terminal spore mass and small, rounded spores. These changes revert when the wild-type triA gene is re-expressed under a constitutive or a psp-specific promoter. By using short- and long-lived reporter proteins, we show that in triA(-) slugs the prestalk (pst)/psp proportion is normal, but that there is inappropriate transdifferentiation between the two cell types. During culmination, regardless of their current fate, all cells with a history of pst gene expression contribute to the stalk, which could account for the altered cell-type proportion in the mutant.
authors.affiliation: Department of Molecular Reproduction Development and Genetics, Indian Institute of Science, Bangalore 560012, India. jaiswaj@rockefeller.edu
authors.forename: Jyoti K
authors.initials: JK
authors.lastname: Jaiswal
authors.forename: Nameeta
authors.initials: N
authors.lastname: Mujumdar
authors.forename: Harry K
authors.initials: HK
authors.lastname: Macwilliams
authors.forename: Vidyanand
authors.initials: V
authors.lastname: Nanjundiah
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle; D002454:Cell Differentiation; D003001:Cloning, Molecular; D004023:Dictyostelium / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D008969:Molecular Sequence Data; D009024:Morphogenesis; D016254:Mutagenesis, Insertional; D009154:Mutation; D010641:Phenotype; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
chemical_list: D015800:Protozoan Proteins