Initial cell type divergence in Dictyostelium is independent of DIF-1.
Prespore and prestalk cells can be distinguished within aggregates of Dictyostelium by the expression of well-characterized cell type-specific genes. Fusion of the tagB regulatory region to Escherichia coli beta-galactosidase revealed that this prestalk specific gene marks the differentiation of the initial prestalk cell population, PST-1. The reporter gene was expressed normally in tagB- mutant cells despite the fact that they do not accumulate measurable levels of DIF-I, a morphogen that was previously implicated in prestalk differentiation. In an independent experimental system, wild-type cells respond to the addition of DIF-I by induction of the prestalk marker ecmA and repression of the prespore marker cotB. We found that DIF-1 did not affect the expression of the tagB or carB genes, both of which are prestalk specific and essential for PST-A cell differentiation. We conclude that the initiation of prestalk development is not dependent on DIF-1 and suggest that the morphogen participates mainly at later stages.
Shaulsky
G
G
Center for Molecular Genetics, Department of Biology, University of California, San Diego, La Jollo, California 92093, USA.
Loomis
W F
WF
D018528:ATP-Binding Cassette Transporters; D000818:Animals; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D002454:Cell Differentiation / Q000235:genetics; D003001:Cloning, Molecular; D004023:Dictyostelium / Q000166:cytology* / Q000235:genetics / Q000254:growth & development; D004926:Escherichia coli / Q000201:enzymology; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D015801:Helminth Proteins / Q000502:physiology*; D006588:Hexanones; D006843:Hydrocarbons, Chlorinated; D011506:Proteins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics; D001616:beta-Galactosidase / Q000235:genetics
D018528:ATP-Binding Cassette Transporters; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; C490570:Differentiation-inducing factor-1, Dictyostelium; D015801:Helminth Proteins; D006588:Hexanones; D006843:Hydrocarbons, Chlorinated; D011506:Proteins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D001616:beta-Galactosidase; C093527:TagB protein, Dictyostelium; D012697:Serine Endopeptidases