RRC ID 3434
Author Hobson RJ, Hapiak VM, Xiao H, Buehrer KL, Komuniecki PR, Komuniecki RW.
Title SER-7, a Caenorhabditis elegans 5-HT7-like receptor, is essential for the 5-HT stimulation of pharyngeal pumping and egg laying.
Journal Genetics
Abstract Serotonin (5-HT) stimulates both pharyngeal pumping and egg laying in Caenorhabditis elegans. Four distinct 5-HT receptors have been partially characterized, but little is known about their function in vivo. SER-7 exhibits most sequence identity to the mammalian 5-HT7 receptors and couples to a stimulation of adenyl cyclase when expressed in COS-7 cells. However, many 5-HT7-specific agonists have low affinity for SER-7. 5-HT fails to stimulate pharyngeal pumping and the firing of the MC motorneurons in animals containing the putative ser-7(tm1325) and ser-7(tm1728) null alleles. In addition, although pumping on bacteria is upregulated in ser-7(tm1325) animals, pumping is more irregular. A similar failure to maintain "fast pumping" on bacteria also was observed in ser-1(ok345) and tph-1(mg280) animals that contain putative null alleles of a 5-HT2-like receptor and tryptophan hydroxylase, respectively, suggesting that serotonergic signaling, although not essential for the upregulation of pumping on bacteria, "fine tunes" the process. 5-HT also fails to stimulate egg laying in ser-7(tm1325), ser-1(ok345), and ser-7(tm1325) ser-1(ok345) animals, but only the ser-7 ser-1 double mutants exhibit an Egl phenotype. All of the SER-7 mutant phenotypes are rescued by the expression of full-length ser-7gfp translational fusions. ser-7gfp is expressed in several pharyngeal neurons, including the MC, M2, M3, M4, and M5, and in vulval muscle. Interestingly, 5-HT inhibits egg laying and pharyngeal pumping in ser-7 null mutants and the 5-HT inhibition of egg laying, but not pumping, is abolished in ser-7(tm1325);ser-4(ok512) double mutants. Taken together, these results suggest that SER-7 is essential for the 5-HT stimulation of both egg laying and pharyngeal pumping, but that other signaling pathways can probably fulfill similar roles in vivo.
Volume 172(1)
Pages 159-69
Published 2006-1
DOI 10.1534/genetics.105.044495
PII genetics.105.044495
PMID 16204223
PMC PMC1456143
MeSH Adenylyl Cyclases / metabolism Animals Behavior, Animal COS Cells Caenorhabditis elegans / genetics Caenorhabditis elegans / growth & development Caenorhabditis elegans / metabolism* Caenorhabditis elegans Proteins / chemistry Caenorhabditis elegans Proteins / metabolism Chlorocebus aethiops Female GTP-Binding Protein alpha Subunits, Gs / genetics GTP-Binding Protein alpha Subunits, Gs / metabolism* Ligands Motor Neurons / metabolism Muscles / physiology Oviposition / drug effects Oviposition / physiology* Pharynx / drug effects Pharynx / metabolism* Phenotype Receptors, Serotonin, 5-HT2 / chemistry Receptors, Serotonin, 5-HT2 / metabolism Repressor Proteins / chemistry Repressor Proteins / metabolism Serotonin / pharmacology* Signal Transduction Tryptophan Hydroxylase / chemistry Tryptophan Hydroxylase / metabolism Vulva / physiology
IF 3.564
Times Cited 78
C.elegans tm1325 tm1728