title: Multiple receptor tyrosine kinases are expressed in adult rat retinal ganglion cells as revealed by single-cell degenerate primer polymerase chain reaction.
abstract: BACKGROUND
  To achieve a better understanding of the repertoire of receptor tyrosine kinases (RTKs) in adult retinal ganglion cells (RGCs) we performed polymerase chain reaction (PCR), using degenerate primers directed towards conserved sequences in the tyrosine kinase domain, on cDNA from isolated single RGCs univocally identified by retrograde tracing from the superior colliculi.
  
  
  RESULTS
  All the PCR-amplified fragments of the expected sizes were sequenced, and 25% of them contained a tyrosine kinase domain. These were: Axl, Csf-1R, Eph A4, Pdgfrbeta, Ptk7, Ret, Ros, Sky, TrkB, TrkC, Vegfr-2, and Vegfr-3. Non-RTK sequences were Jak1 and 2. Retinal expression of Axl, Csf-1R, Pdgfrbeta, Ret, Sky, TrkB, TrkC, Vegfr-2, and Vegfr-3, as well as Jak1 and 2, was confirmed by PCR on total retina cDNA. Immunodetection of Csf-1R, Pdgfralpha/beta, Ret, Sky, TrkB, and Vegfr-2 on retrogradely traced retinas demonstrated that they were expressed by RGCs. Co-localization of Vegfr-2 and Csf-1R, of Vegfr-2 and TrkB, and of Csf-1R and Ret in retrogradely labelled RGCs was shown. The effect of optic nerve transection on the mRNA level of Pdgfrbeta, Csf-1R, Vegfr-2, Sky, and Axl, and of the Axl ligands Gas6 and ProteinS, was analysed. These analyses show transection-induced changes in Axl and ProteinS mRNA levels.
  
  
  CONCLUSIONS
  The repertoire of RTKs expressed by RGCs is more extensive than previously anticipated. Several of the receptors found in this study, including Pdgfrbeta, Csf-1R, Vegfr-2, Sky, and Axl, and their ligands, have not previously been primarily associated with retinal ganglion cells.
authors.affiliation: Department of Neuroscience, Unit for Developmental Neuroscience, Biomedical Center, Uppsala University, 75123 Uppsala, Sweden.
authors.forename: Niclas
authors.initials: N
authors.lastname: Lindqvist
authors.forename: Ulrika
authors.initials: U
authors.lastname: Lönngren
authors.forename: Marta
authors.initials: M
authors.lastname: Agudo
authors.forename: Ulla
authors.initials: U
authors.lastname: Näpänkangas
authors.forename: Manuel
authors.initials: M
authors.lastname: Vidal-Sanz
authors.forename: Finn
authors.initials: F
authors.lastname: Hallböök
mesh_terms: D000818:Animals; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D008024:Ligands; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods*; D017434:Protein Structure, Tertiary; D051381:Rats; D017207:Rats, Sprague-Dawley; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D012160:Retina / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000166:cytology*; D012737:Sex Factors
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D008024:Ligands; D020794:Receptor Protein-Tyrosine Kinases