The cAMP receptor CAR4 regulates axial patterning and cellular differentiation during late development of Dictyostelium.
Pseudoplasmodia of developing Dictyostelium are organized with anteroposterior polarity. We have isolated CAR4, the gene for a new cell-surface, G protein-linked cAMP receptor. CAR4 mRNA is initially expressed during tip elongation and continues to accumulate into culmination. CAR4 is maximally expressed in pseudoplasmodia anteriors which are centers for extracellular cAMP signaling and for organization of cellular patterning. Although car4 null cells progress unperturbed through early development, they exhibit major patterning aberrations as the anteroposterior axis becomes established. Prestalk gene expression is significantly reduced in car4 nulls, whereas prespore-specific markers are overexpressed and detected in zones normally restricted to prestalk cells. Patterning defects are similarly apparent in terminally differentiated fruiting bodies. Our results show that cAMP signaling is required for pattern formation and cellular differentiation during late Dictyostelium development.
Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.
J M
JM
Louis
G T
GT
Ginsburg
A R
AR
Kimmel
D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D018076:DNA, Complementary / Q000235:genetics; D004023:Dictyostelium / Q000235:genetics / Q000254:growth & development*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D005800:Genes, Fungal; D017125:Genes, Protozoan; D005819:Genetic Markers; D008969:Molecular Sequence Data; D015800:Protozoan Proteins; D011953:Receptors, Cyclic AMP / Q000235:genetics / Q000502:physiology*; D011995:Recombination, Genetic; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
C090317:CAR4 protein, Dictyostelium discoideum; D018076:DNA, Complementary; D005819:Genetic Markers; D015800:Protozoan Proteins; D011953:Receptors, Cyclic AMP; D019204:GTP-Binding Proteins