title: Soma-restricted products of the myelin proteolipid gene are expressed primarily in neurons in the developing mouse nervous system.
abstract: The myelin proteolipid gene encodes two sets of proteins, the classic PLP and DM20 and the sr (soma-restricted)-PLP and sr-DM20. Unlike the classic proteolipids, the sr-products are expressed in both neurons and oligodendrocytes (OLs) and are not components of the myelin sheath. In OLs, the sr-isoforms are associated with endosomes and recycling vesicles indicating a possible nonmyelin function for these proteins. In this study, a purified antibody specific for the sr-products was used to examine the expression of these proteins during the development of the mouse brain. We found that while sr-PLP and sr-DM20 are expressed in OLs, the highest levels of immunoreactivity were found in neuronal populations. During early embryonic development (E13-E15), sr-proteolipids were detected in the dorsal root ganglion and motor neurons in the spinal cord. By E17, immunostaining for sr-PLP and sr-DM20 in the brain increased dramatically. The highest levels of immunoreactivity were found during the first and second weeks postnatal after which staining intensity declined to adult levels and the pattern of expression was more restricted. Robust staining persisted in many neuronal populations including nuclei in the hindbrain, Purkinje and granule neurons in the cerebellum, pyramidal cells in the cortex and mitral cells in the olfactory bulb. The spatial and temporal pattern of sr-PLP and sr-DM20 expression is very similar to that of the endosomal protein, syntaxin 13, consistent with the finding that the sr-PLPs may play a role in vesicular transport in neurons.
authors.affiliation: Developmental and Molecular Neuroscience Group, Neuropsychiatric Institute, UCLA School of Medicine, Los Angeles, Calif 90024-17519, USA. ejacobs@mednet.ucla.edu
authors.forename: Erin C
authors.initials: EC
authors.lastname: Jacobs
authors.forename: Ernesto R
authors.initials: ER
authors.lastname: Bongarzone
authors.forename: Celia W
authors.initials: CW
authors.lastname: Campagnoni
authors.forename: Kathy
authors.initials: K
authors.lastname: Kampf
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Campagnoni
mesh_terms: D000818:Animals; D001921:Brain / Q000196:embryology; D004622:Embryo, Mammalian; D005314:Embryonic and Fetal Development / Q000235:genetics*; D005260:Female; D005727:Ganglia, Spinal / Q000196:embryology; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D051379:Mice; D018991:Myelin Proteolipid Protein / Q000096:biosynthesis* / Q000235:genetics*; D009474:Neurons / Q000166:cytology*; D009836:Oligodendroglia / Q000166:cytology; D011247:Pregnancy; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics; D013116:Spinal Cord / Q000196:embryology
chemical_list: D018991:Myelin Proteolipid Protein; D020033:Protein Isoforms