An essential Drosophila glutamate receptor subunit that functions in both central neuropil and neuromuscular junction.
A Drosophila forward genetic screen for mutants with defective synaptic development identified bad reception (brec). Homozygous brec mutants are embryonic lethal, paralyzed, and show no detectable synaptic transmission at the glutamatergic neuromuscular junction (NMJ). Genetic mapping, complementation tests, and genomic sequencing show that brec mutations disrupt a previously uncharacterized ionotropic glutamate receptor subunit, named here "GluRIID." GluRIID is expressed in the postsynaptic domain of the NMJ, as well as widely throughout the synaptic neuropil of the CNS. In the NMJ of null brec mutants, all known glutamate receptor subunits are undetectable by immunocytochemistry, and all functional glutamate receptors are eliminated. Thus, we conclude that GluRIID is essential for the assembly and/or stabilization of glutamate receptors in the NMJ. In null brec mutant embryos, the frequency of periodic excitatory currents in motor neurons is significantly reduced, demonstrating that CNS motor pattern activity is regulated by GluRIID. Although synaptic development and molecular differentiation appear otherwise unperturbed in null mutants, viable hypomorphic brec mutants display dramatically undergrown NMJs by the end of larval development, suggesting that GluRIID-dependent central pattern activity regulates peripheral synaptic growth. These studies reveal GluRIID as a newly identified glutamate receptor subunit that is essential for glutamate receptor assembly/stabilization in the peripheral NMJ and required for properly patterned motor output in the CNS.
Featherstone
David E
DE
Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607, USA. def@uic.edu
Rushton
Emma
E
Rohrbough
Jeffrey
J
Liebl
Faith
F
Karr
Julie
J
Sheng
Qi
Q
Rodesch
Christopher K
CK
Broadie
Kendal
K
D000818:Animals; D030801:Animals, Genetically Modified; D004330:Drosophila; D029721:Drosophila Proteins / Q000172:deficiency / Q000378:metabolism / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D004625:Embryo, Nonmammalian; D019706:Excitatory Postsynaptic Potentials / Q000235:genetics / Q000528:radiation effects; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D018613:Microscopy, Confocal / Q000379:methods; D008967:Molecular Biology / Q000379:methods; D009469:Neuromuscular Junction / Q000502:physiology*; D019581:Neuropil / Q000378:metabolism*; D018408:Patch-Clamp Techniques / Q000379:methods; D021122:Protein Subunits / Q000172:deficiency / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D017470:Receptors, Glutamate / Q000172:deficiency / Q000502:physiology*; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D051025:bcl-Associated Death Protein / Q000172:deficiency
D029721:Drosophila Proteins; D021122:Protein Subunits; D016271:Proto-Oncogene Proteins c-myc; D017470:Receptors, Glutamate; D025521:Tumor Suppressor Proteins; D051025:bcl-Associated Death Protein; C483908:glutamate receptor III, Drosophila; C070350:dlg1 protein, Drosophila; D049452:Green Fluorescent Proteins