Production and activity of spore differentiation factors (SDFs) in Dictyostelium.
SDF-1 and SDF-2 are peptides that promote terminal spore differentiation under submerged conditions. The present study shows that they accumulate differentially and are released during the development of wild-type cells and can promote spore formation in cells disaggregated from wild-type culminants. SDF-1 accumulates during the slug stage and is released in a single burst at the onset of culmination while SDF-2 accumulates during early culmination and is released in a single burst from mid-culminants. The effects of SDF-1 and SDF-2 on stalk cell formation in cell monolayers were investigated. SDF-1 by itself induces stalk cell formation in some strains and also synergizes with the stalk-cell-inducing factor, DIF-1. cAMP has an inhibitory effect on stalk cell formation when either DIF-1 or SDF-1 are present on their own but is almost not inhibitory when both are present. SDF-2 alone does not induce stalk cell formation and appears to inhibit the response to DIF-1. At the same time, it increases the extent of vacuolization of the stalk cells that are produced. We propose that the release of SDF-1 and then of SDF-2 may mark irreversible steps in the developmental programme associated, respectively, with culmination and spore maturation.
Anjard
C
C
Universität Kassel, Abt. Genetik, Heinrich-Plett-Strasse 40, D-34 132 Kassel, Germany.
Chang
W T
WT
Gross
J
J
Nellen
W
W
D000818:Animals; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins / Q000494:pharmacology; D002449:Cell Aggregation; D002454:Cell Differentiation; D002460:Cell Line; D000242:Cyclic AMP / Q000494:pharmacology; D004023:Dictyostelium / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D015801:Helminth Proteins / Q000494:pharmacology; D006588:Hexanones; D006843:Hydrocarbons, Chlorinated; D008018:Life Cycle Stages; D011506:Proteins; D015800:Protozoan Proteins / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D013170:Spores / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors
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; D000242:Cyclic AMP