Cell-specific manipulation of second messengers; a toolbox for integrative physiology in Drosophila.
Every living cell must detect, and respond appropriately to, external signals. The functions of intracellular second messengers, such as guanosine 3'5'-cyclic monophosphate (cGMP), adenosine 3'5'-cyclic monophosphate (cAMP), and intracellular calcium, are thus intensively studied. However, artifact-free manipulation of these messengers is problematic, and simple pharmacology may not allow selective intervention in distinct cell types in a real, complex tissue. We have devised a method by which second messenger levels can be manipulated in cells of choice using the GAL4/UAS system. By placing different receptors (rat atrial natriuretic peptide [ANP] receptor and Drosophila serotonin receptors [5HT(Dro7) and 5HT(Dro1A)]) under UAS control, they can be targeted to arbitrary defined populations of cells in any tissue of the fly, and second messenger levels can be manipulated simply by adding the natural ligand. The potential of the system is illustrated in the Drosophila renal (Malpighian) tubule, where each receptor was shown to stimulate fluid secretion, to act through its cognate second messenger, and to be blocked by appropriate pharmacological antagonists. The results uncovered a new role for cGMP signaling in tubule and also demonstrate the utility of the tubule as a possible in vivo test bed for novel receptors, ligands, or agonists/antagonists.
IBLS Division of Molecular Genetics, University of Glasgow, Glasgow G11 6NU, United Kingdom.
Martin
M
Kerr
Shireen A
SA
Davies
Julian A T
JA
Dow
D000331:Aequorin; D000818:Animals; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004330:Drosophila / Q000378:metabolism* / Q000502:physiology; D029721:Drosophila Proteins; D008024:Ligands; D008317:Malpighian Tubules / Q000378:metabolism* / Q000502:physiology; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D010456:Peptides, Cyclic / Q000494:pharmacology; D010827:Physiology / Q000379:methods; D011863:Radioimmunoassay; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor / Q000037:antagonists & inhibitors / Q000378:metabolism; D011985:Receptors, Serotonin; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015290:Second Messenger Systems / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D019076:Transgenes
C098813:5-HT7 protein, Drosophila; D029721:Drosophila Proteins; D008024:Ligands; D008562:Membrane Glycoproteins; D010456:Peptides, Cyclic; D011985:Receptors, Serotonin; C068090:anantin; D000331:Aequorin; D000242:Cyclic AMP; D017461:Receptors, Atrial Natriuretic Factor; D006152:Cyclic GMP; D002118:Calcium