Rap1gap2 regulates axon outgrowth in olfactory sensory neurons.
Olfactory sensory neurons (OSNs) extend their axons from the nasal epithelium to their odorant receptor-dependent locations in the olfactory bulb. Previous studies have identified several membrane proteins along the projection pathway, and on OSN axons themselves, which regulate this process; however, little is known about the signaling mechanisms through which these factors act. We have identified and characterized Rap1gap2, a novel small GTPase regulator, in OSNs during early postnatal mouse development. Rap1gap2 overexpression limits neurite outgrowth and branching in Neuro-2a cells, and counteracts Rap1-induced augmentation of neurite outgrowth. Rap1gap2 expression is developmentally regulated within OSNs, with high expression in early postnatal stages that ultimately drops to undetectable levels by adulthood. This temporal pattern coincides with an early postnatal plastic period of OSN innervation refinement at the OB glomerular layer. Rap1gap2 stunts OSN axon outgrowth when overexpressed in vitro, while knock-down of Rap1gap2 transcript results in a significant increase in axon length. These results indicate an important role of Rap1gap2 in OSN axon growth dynamics during early postnatal development.
Department of Cell Biology and Human Anatomy, University of California, Davis, School of Medicine, Davis, CA 95616, USA. basadrian@ucdavis.edu
Benjamin
B
Sadrian
Ting-Wen
TW
Cheng
Olivia
O
Shull
Qizhi
Q
Gong
D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000378:metabolism*; D002460:Cell Line; D020690:GTPase-Activating Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D008969:Molecular Sequence Data; D018034:Olfactory Receptor Neurons / Q000254:growth & development / Q000378:metabolism*; D034741:RNA, Small Interfering; D014158:Transcription, Genetic; D020827:rap1 GTP-Binding Proteins / Q000378:metabolism
D020690:GTPase-Activating Proteins; D034741:RNA, Small Interfering; C576346:Rap1gap2 protein, mouse; D020827:rap1 GTP-Binding Proteins