Messenger RNAs for trk and the low-affinity NGF receptor in rat basal forebrain.
Nerve growth factor (NGF) acts by binding to specific sets of neurons. Low-affinity binding (Kd of 10(-9) M) is mediated via a 75 kDa glycoprotein (LNGFR). Recently, a 140 kDa tyrosine protein kinase encoded by the proto-oncogene trk has been found to bind NGF with high affinity (Kd of 10(-11) M) and to evoke neurotrophic responses. In addition, the related trkB protein and the LNGFR have been shown to bind brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) with an affinity of Kd 10(-9) M. We demonstrate the distribution of mRNA encoding the neurotrophin-binding proteins in the forebrain of the 21-day-old Sprague-Dawley rat by in-situ hybridization. Expression of trk and LNGFR mRNA showed co-localization and was restricted to the medial septal nucleus and the nucleus of Broca's diagonal band, suggesting a receptor function in these cells for both proteins encoded. In contrast, expression of trkB was widely spread in many areas. Thus trkB protein might serve general functions in the forebrain.
Vazquez
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ME
Department of Developmental Biology, Uppsala University, Sweden.
Ebendal
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D000375:Aging; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis; D016376:Oligonucleotides, Antisense / Q000138:chemical synthesis; D015513:Oncogene Proteins / Q000235:genetics*; D009857:Oncogenes; D016548:Prosencephalon / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D000090063:Proto-Oncogene Mas; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics*; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D017475:Receptors, Nerve Growth Factor
C000715470:MAS1 protein, human; D008562:Membrane Glycoproteins; D009414:Nerve Growth Factors; D009838:Oligodeoxyribonucleotides; D016376:Oligonucleotides, Antisense; D015513:Oncogene Proteins; D000090063:Proto-Oncogene Mas; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D017475:Receptors, Nerve Growth Factor; C065400:oncogene protein trk; D004247:DNA