Cyclic AMP enhances the sexual agglutinability of Chlamydomonas flagella.
Sexual adhesion between Chlamydomonas reinhardtii gametes elicits a rise in intracellular cAMP levels, and exogenous elevation of intracellular cAMP levels in gametes of a single mating type induces such mating responses as cell wall loss, flagellar tip activation, and mating structure activation (Pasquale, S. M., and U. W. Goodenough. 1987. J. Cell Biol. 105:2279-2292). Here evidence is presented that sexual adhesion mobilizes agglutinin to the flagellar surface, and that this mobilization can be induced by exogenous presentation of cAMP to gametes of a single mating type. It is proposed that Chlamydomonas adhesion entails a positive feedback system--initial contacts stimulate the presentation of additional agglutinin--and that this feedback is mediated by adhesion-induced cAMP generation.
Goodenough
U W
UW
Department of Biology, Washington University, St. Louis, Missouri 63130.
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000373:Agglutinins / Q000502:physiology*; D003994:Bucladesine / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D002449:Cell Aggregation / Q000187:drug effects; D002451:Cell Compartmentation; D002696:Chlamydomonas / Q000502:physiology*; D000242:Cyclic AMP / Q000502:physiology*; D003593:Cytoplasm / Q000378:metabolism; D005407:Flagella / Q000502:physiology / Q000648:ultrastructure; D005613:Freeze Etching; D012098:Reproduction
D000373:Agglutinins; D003994:Bucladesine; D000242:Cyclic AMP; D015056:1-Methyl-3-isobutylxanthine