title: Ribosomal distributions in axons of mammalian myelinated fibers.
abstract: The distribution of ribosomes and polysomes in uninjured myelinated axons of rat sciatic nerve was analyzed. Ribosomes were identified by immunocytochemistry at the light and electron microscopic levels. A polyclonal antibody developed against ribosomes recognized both rRNA and ribosomal proteins. The distribution of the immunoreaction product was similar to that obtained with human anti-ribosomal P protein. The immunoreaction product distributions were of two types in axons: 1) periodic localization in the cortical region of axoplasm that appeared as a compact structural aggregate, consistent with that described as a periaxoplasmic ribosomal plaques (PARP) domain (Koenig et al. [2000] J. Neurosci. 20:8390-8400), and 2) scattered small immuno-reactive clusters of varying sizes (RNP) within the central core of the axon. The latter observation suggested the possibility that RNP-like particles could be associated with the axonal transport system and in transit. Immunoreaction product was also associated with a novel structural inclusion, possibly multi-vesicular in makeup that was located in the axon and at the myelin-axon interface, and visible at the light and EM levels. The potential significance of this structural peculiarity is considered.
authors.affiliation: Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Kun
authors.forename: Leonardo
authors.initials: L
authors.lastname: Otero
authors.forename: José R
authors.initials: JR
authors.lastname: Sotelo-Silveira
authors.forename: José R
authors.initials: JR
authors.lastname: Sotelo
mesh_terms: D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure*; D012335:RNA, Ribosomal / Q000378:metabolism; D051381:Rats; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D012584:Sciatic Nerve / Q000648:ultrastructure; D014018:Tissue Distribution
chemical_list: D012335:RNA, Ribosomal; D012269:Ribosomal Proteins