title: Expression of PTPRO during mouse development suggests involvement in axonogenesis and differentiation of NT-3 and NGF-dependent neurons.
abstract: Competition and cooperation between type II and type III receptor protein tyrosine phosphatases (RPTPs) regulate axon extension and pathfinding in Drosophila. The first step to investigate whether RPTPs influence axon growth in the more complex vertebrate nervous system is to identify which neurons express a particular RPTP. We studied the expression of mouse PTPRO, a type III RPTP with an extracellular region containing eight fibronectin type III domains, during embryogenesis and after birth. Mouse PTPRO mRNA is expressed exclusively in two cell types: neurons and kidney podocytes. Maximal expression in the brain was coincident with mid to late gestation and axonogenesis in the brain. We cloned two cDNAs, including a splice variant without sequence coding of 28 amino acids within the juxtamembrane domain that was found mostly in kidney. In situ hybridization detected mPTPRO mRNA in the cerebral cortex, olfactory bulb and nucleus, hippocampus, motor neurons, and the spinal cord midline. In addition, mPTPRO mRNA was found throughout dorsal root, cranial, and sympathetic ganglia and within kidney glomeruli. Mouse PTPRO mRNA was observed in neuron populations expressing TrkA, the high-affinity nerve growth factor receptor, or TrkC, the neurotrophin-3 receptor, and immunoreactive mPTPRO and TrkC colocalized in large dorsal root ganglia proprioceptive neurons. Our results suggest that mPTPRO is involved in the differentiation and axonogenesis of central and peripheral nervous system neurons, where it is in a position to modulate intracellular responses to neurotrophin-3 and/or nerve growth factor.
authors.affiliation: The Neuroscience Program and Department of Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, Florida 33136, USA.
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Beltran
authors.forename: John L
authors.initials: JL
authors.lastname: Bixby
authors.forename: Brian A
authors.initials: BA
authors.lastname: Masters
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001369:Axons / Q000378:metabolism*; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002454:Cell Differentiation; D002874:Chromosome Mapping; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007668:Kidney / Q000254:growth & development / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D020932:Nerve Growth Factor / Q000378:metabolism*; D009420:Nervous System / Q000254:growth & development / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D020933:Neurotrophin 3 / Q000378:metabolism*; D017933:Peripheral Nervous System / Q000378:metabolism; D016133:Polymerase Chain Reaction; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020917:Receptor, trkA; D020812:Receptor, trkC / Q000378:metabolism; D054631:Receptor-Like Protein Tyrosine Phosphatases, Class 3; D013116:Spinal Cord / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D020933:Neurotrophin 3; D012333:RNA, Messenger; D020932:Nerve Growth Factor; D020917:Receptor, trkA; D020812:Receptor, trkC; D017027:Protein Tyrosine Phosphatases; C516890:Ptpro protein, mouse; D054631:Receptor-Like Protein Tyrosine Phosphatases, Class 3