title: Regulation of chemotropic guidance of nerve growth cones by microRNA.
abstract: BACKGROUND
  The small non-coding microRNAs play an important role in development by regulating protein translation, but their involvement in axon guidance is unknown. Here, we investigated the role of microRNA-134 (miR-134) in chemotropic guidance of nerve growth cones.
  
  
  RESULTS
  We found that miR-134 is highly expressed in the neural tube of Xenopus embryos. Fluorescent in situ hybridization also showed that miR-134 is enriched in the growth cones of Xenopus spinal neurons in culture. Importantly, overexpression of miR-134 mimics or antisense inhibitors blocked protein synthesis (PS)-dependent attractive responses of Xenopus growth cones to a gradient of brain-derived neurotrophic factor (BDNF). However, miR-134 mimics or inhibitors had no effect on PS-independent bidirectional responses of Xenopus growth cones to bone morphogenic protein 7 (BMP7). Our data further showed that Xenopus LIM kinase 1 (Xlimk1) mRNA is a potential target of miR-134 regulation.
  
  
  CONCLUSIONS
  These findings demonstrate a role for miR-134 in translation-dependent guidance of nerve growth cones. Different guidance cues may act through distinct signaling pathways to elicit PS-dependent and -independent mechanisms to steer growth cones in response to a wide array of spatiotemporal cues during development.
authors: Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors: Liang
authors: L
authors: Han
authors: Zhexing
authors: Z
authors: Wen
authors: Rachel C
authors: RC
authors: Lynn
authors: Marie-Laure
authors: ML
authors: Baudet
authors: Christine E
authors: CE
authors: Holt
authors: Yukio
authors: Y
authors: Sasaki
authors: Gary J
authors: GJ
authors: Bassell
authors: James Q
authors: JQ
authors: Zheng
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology; D002633:Chemotaxis / Q000187:drug effects; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000187:drug effects; D020439:Growth Cones / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D008954:Models, Biological; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D014981:Xenopus; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D035683:MicroRNAs; D016376:Oligonucleotides, Antisense; D029867:Xenopus Proteins; D019950:Mitogen-Activated Protein Kinase 1