cAMP and DIF-1 repress the expression of the Dictyostelium MADS-box gene srfA at early stages of development.
The MADS-box-containing gene srfA from Dictyostelium discoideum codes for a putative transcription factor that plays multiple roles in the development of this social amoeba. We have investigated the regulation of srfA gene expression after disaggregation of the cells from developing structures. The steady-state level of srfA mRNA was strongly and transiently induced shortly after disaggregation. srfA is maximally expressed 20 min after cell disaggregation and decreases thereafter. Induction was not dependent on protein synthesis, PKA, the kinase SplA and SrfA itself. This phenomena does not occur when cells are disaggregated in a small volume of buffer, suggesting the presence of extracellular molecules that repress srfA gene expression. To test this hypothesis, several well-known extracellular signaling molecules were studied. We found that srfA mRNA induction can be efficiently repressed by addition of exogenous cAMP and DIF-1 to the buffer in which the cells were disaggregated. Addition of other extracellular compounds such as ammonia, adenosine, SDF-1, and SDF-2 had no effect. srfA promoter P2, specifically induced during slug migration, was responsible for this regulation by extracellular compounds.
Escalante
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Instituto de Investigaciones Biomédicas del Consejo Superior de Investigaciones Científicas, C/Arturo Duperier, 4, 28029 Madrid, Spain. rescalante@iib.uam.es
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D000241:Adenosine / Q000494:pharmacology; D000641:Ammonia / Q000494:pharmacology; D000818:Animals; D001426:Bacterial Proteins; D002449:Cell Aggregation / Q000187:drug effects / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism* / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D004023:Dictyostelium; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology*; D006588:Hexanones / Q000378:metabolism* / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism*; D010455:Peptides; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011506:Proteins / Q000494:pharmacology; D015800:Protozoan Proteins; D012333:RNA, Messenger / Q000096:biosynthesis; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D004791:Enzyme Inhibitors; D006588:Hexanones; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D011500:Protein Synthesis Inhibitors; D011506:Proteins; D015800:Protozoan Proteins; D012333:RNA, Messenger; C484455:SDF-2 protein, Dictyostelium discoideum; D014157:Transcription Factors; C053433:1-((3,5-dichloro)-2,6-dihydroxy-4-methoxyphenyl)-1-hexanone; D000641:Ammonia; D000242:Cyclic AMP; C102073:SplA protein, Dictyostelium discoideum; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D010453:Peptide Synthases; C069542:surfactin synthetase; D000241:Adenosine