Positively and negatively acting signals regulating stalk cell and anterior-like cell differentiation in Dictyostelium.
The Dictyostelium ecmB gene encodes an extracellular matrix protein and is inducible by the stalk cell morphogen DIF. It is expressed in a subset of prestalk (pstB) cells in the slug and surrounding pstA cells first express it at culmination. A region of the ecmB promoter can direct transcription in all anterior prestalk cells, but a separate, downstream region acts to prevent its expression in pstA cells prior to culmination. This may be the site of interaction of a repressor, regulated by an extracellular antagonist to DIF. At culmination, expression of the ecmB gene also becomes greatly elevated in anterior-like cells as they move to surround the spore mass. A distal region of the ecmB promoter directs increased expression in those anterior-like cells that surmount the spore head. This divergence in gene expression suggests that anterior-like cells and anterior prestalk cells experience different inductive conditions at culmination.
Ceccarelli
A
A
Imperial Cancer Research Fund, Clare Hall Laboratories, Potters Bar, Hertfordshire, England.
Mahbubani
H
H
Williams
J G
JG
D001483:Base Sequence; D002454:Cell Differentiation; D004252:DNA Mutational Analysis; D004271:DNA, Fungal / Q000235:genetics; D004023:Dictyostelium / Q000166:cytology* / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009024:Morphogenesis; D011401:Promoter Regions, Genetic; D015800:Protozoan Proteins; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping
D004271:DNA, Fungal; D016326:Extracellular Matrix Proteins; D005656:Fungal Proteins; D015800:Protozoan Proteins; C069214:ecmB protein, Dictyostelium