RRC ID 28982
Author Saxe CL 3rd, Yu Y, Jones C, Bauman A, Haynes C.
Title The cAMP receptor subtype cAR2 is restricted to a subset of prestalk cells during Dictyostelium development and displays unexpected DIF-1 responsiveness.
Journal Dev Biol
Abstract Dictyostelium discoidium cells express a family of cell surface cAMP receptors, and these G-protein-coupled receptors are each expressed with unique spatial and temporal patterns. One of these receptors, cAR2, is present during the postaggregative stages of development and our previous work suggests that it is preferentially expressed in prestalk cells. We report here the isolation of the promoter for carB, the gene which encodes cAR2. Using this fragment to generate a carB::lacZ, gene fusion construct, we investigated carB expression in detail. Expression is first detected at the tight aggregate stage and subsequently in a pattern reminiscent of the prestalk-specific gene ecmA. There are subtle differences, however, with, ecmA being expressed significantly in the anterior-like cells of the migrating pseudoplasmodium and in the basal disc and lower cup supporting the sorus during terminal development. carB is not expressed in any of these places. The presence of these different prestalk cell subtypes was confirmed by double indirect immunofluorescence using anti-cAR2 and anti-beta-galactosidase antibodies. While virtually all cAR2-expressing cells also express ecmA::lacZ, a substantial fraction of ecmA::lacZ-positive cells do not express cAR2. We also found the regulation of carB gene expression to differ from that of ecmA. carB expression is induced in vitro by extracellular cAMP, but surprisingly, not by DIF-1, a soluble molecule thought to be essential for the initiation of prestalk differentiation. Thus, cAR2 appears to be a cAMP receptor present on a restricted subset of prestalk cells and whose expression does not respond typically to the prestalk inducer DIF-1. DIF-1 sensitivity may, therefore, not be characteristic of all early prestalk differentiation.
Volume 174(2)
Pages 202-13
Published 1996-3-15
DOI 10.1006/dbio.1996.0066
PII S0012160696900664
PMID 8631493
MeSH Amino Acid Sequence Animals Caenorhabditis elegans Proteins* Carrier Proteins / metabolism* Dictyostelium / cytology Dictyostelium / metabolism* Fluorescent Antibody Technique Helminth Proteins / metabolism* Hexanones Hydrocarbons, Chlorinated Molecular Sequence Data Plasmids Proteins* Receptors, Cyclic AMP / genetics Receptors, Cyclic AMP / metabolism*
IF 2.896
Times Cited 34
Cellular slime molds S90310 S90362 G90042