rpm-1, a conserved neuronal gene that regulates targeting and synaptogenesis in C. elegans.
Little is known of mechanisms regulating presynaptic differentiation. We identified rpm-1 in a screen for mutants with defects in patterning of a presynaptic marker at certain interneuronal synapses. The predicted RPM-1 protein contains zinc binding, RCC1, and other conserved motifs. In rpm-1 mutants, mechanosensory neurons fail to accumulate tagged vesicles, retract synaptic branches, and ectopically extend axons. Some motor neurons branch and overgrow; others show altered synaptic organization. Expression of RPM-1 in the presynaptic mechanosensory neurons is sufficient to rescue phenotypes in these cells. Certain rpm-1 phenotypes are temperature sensitive, revealing that RPM-1 function can be bypassed by maintaining mutants at the permissive temperature at stages commensurate with synapse formation in wild-type animals. These results indicate that RPM-1 functions cell autonomously during synaptogenesis to regulate neuronal morphology.
Schaefer
A M
AM
Department of Anatomy and Neurobiology, Washington University School of Medicine, Saint Louis, Missouri 63110, USA.
Hadwiger
G D
GD
Nonet
M L
ML
D000818:Animals; D017173:Caenorhabditis elegans / Q000033:anatomy & histology / Q000235:genetics* / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins; D017124:Conserved Sequence / Q000235:genetics; D018390:Gene Targeting; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D008465:Mechanoreceptors / Q000502:physiology; D008969:Molecular Sequence Data; D009046:Motor Neurons / Q000648:ultrastructure; D009154:Mutation / Q000502:physiology; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000648:ultrastructure; D013696:Temperature
D029742:Caenorhabditis elegans Proteins; D020662:Guanine Nucleotide Exchange Factors; C409634:RPM-1 protein, C elegans