Ontogenetic Changes in Myelin Protein Composition in Different Regions of Rat Central Nervous System

Zgorzalewicz, B; Neuhoff, Volker; Waehneldt, Thomas V.

doi:10.1515/znc-1974-1-225

Cited by 4 publications

(5 citation statements)

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“…Therefore, it was concluded that the relative amounts ofBP and PLP are not necessarily constant in different fibers even in the mature myelin membrane. This conclusion is consistent with previous biochemical measurements that have shown a difference in the ratio ofBP and PLP in myelin subfractions separated on sucrose density gradients (13)(14)(15) and in myelin prepared from different brain regions (15)(16)(17). Other myelin-specific proteins might be expected to show similar heterogeneity in concentration.…”

supporting

confidence: 93%

Development and maturation of central nervous system myelin: Comparison of immunohistochemical localization of proteolipid protein and basic protein in myelin and oligodendrocytes

Hartman

Agrawal

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

135

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The immunohistochemical localization oftwo myelin-specific proteins-basic protein (BP) and proteolipid protein (PLP)-was compared during the process of myelination. Although both proteins were present in oligodendrocytes, (i) neither protein was observed in oligodendrocytes not already closely associated with nerve fibers exhibiting a fluorescent coating; (ii) in any discrete anatomical area oligodendrocytes were positive for BP before PLP was visible; and (iii) as myelination progressed, immunoreactivity for BP in oligodendrocytes appeared to decrease and simultaneously PLP immunofluorescence became visible in this cell type. During the period of active myelination, fibers exhibited a distinct varicose appearance. As myelination progressed, the myelin sheath increased in thickness and these varicosities became less prominent, eventually completely disappearing. Therefore, the nature and the appearance ofvaricosities can be used as an index ofthe relative stage ofmaturation ofmyelin in an individual fiber. In general, PLP appeared in fibers at a later stage ofmaturation than did BP based on the above criteria. However, in a relatively small number offine fibers PLP was observed at a very early stage. In fully mature myelin, very large fibers were frequently more intensely fluorescent for BP than PLP, whereas fine myelinated fibers were more intensely stained for PLP. These observations are consistent with the following interpretations. (i) Substantial differentiation of oligodendrocytes occurs prior to appearance of either of these proteins by immunofluorescence. (ii) BP is added to the myelin sheath prior to PLP and there appears to be a shift in priority of synthesis from BP to PLP in individual oligodendrocytes during the process of myelination. (iii) Very small fibers often contain low concentrations ofBP relative to PLP, and conversely, very large fibers may contain a high concentration of BP relative to PLP. Thus, the relative concentration of these proteins in myelin appears not to be constant but may vary as a function of the size of the myelinated fiber.Proteolipid protein (PLP) and basic protein (BP)-the major structural proteins of central nervous system myelin-account for 50% and 30%, respectively, of the total myelin membrane proteins ofrat brain (1-2). The limited solubility of myelin PLP in aqueous solution has posed a persistent problem in the purification of PLP for further biochemical and immunological characterization. Techniques for the isolation ofan antigenically active preparation of myelin PLP have been developed in this laboratory (3). Specific precipitating antibodies to homogeneous preparations ofboth PLP and BP isolated from rat brain myelin have been produced. The purity and specificity ofthese antisera have been established by immunodiffusion and cross immunoadsorption (3,4). The antisera to PLP and BP were used for the immunohistochemical localization of these proteins in the central nervous system. The results of the immunohistochemical studies in adult brain established ...

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supporting

confidence: 93%

Development and maturation of central nervous system myelin: Comparison of immunohistochemical localization of proteolipid protein and basic protein in myelin and oligodendrocytes

Hartman

Agrawal

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

135

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“…During ontogeny myelin proteins are rapidly accumulating from 0.19mg of protein/g of forebrain of 15-day-old animals to 7.6mg of protein/g of forebrain of adult animals. These data are consistent with previous observations Zgorzalewicz et a!., 1974). Fraction SN 4, by contrast, contains only 0.045mg of protein/g of forebrain of 15-day-old animals and gradually increases to 0.5mg of protein/g of forebrain of adult animals, implying that only small amounts of membrane fragments are found in the supernatant of hypoosmotically shocked microsome-free myelin after differential centrifugation.…”

supporting

confidence: 93%

“…11 times that ofthe total homogenate) have yet been described for an untreated membrane fraction; still higher cyclic nucleotide 3'-phosphohydrolase activities have been reported, however, for solubilized bovine brain cyclic nucleotide 3'-phosphohydrolase (Guha & Moore, 1975). The values for the total homogenate and for myelin agree with those of Agrawal et al (1973,1974), particularly when it is considered that these authors examined total brain from 15-day-old animals, which represents a later stage in overall myelination (Zgorzalewicz et al, 1974), as compared with the forebrain used in the experiments described in the present paper. It was observed that fraction SN 4 of forebrain from 15-dayold animals exhibits more than twice the cyclic nucleotide 3'-phosphohydrolase activityofthemyelinlike fraction of total brain from 15-day-old animals (Agrawal et al, 1973).…”

supporting

confidence: 90%

Ontogenetic study of a myelin-derived fraction with 2′:3′-cyclic nucleotide 3′-phosphodydrolase activity higher than that of myelin

Waehneldt¹

1975

Biochemical Journal

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A membrane fraction (SN 4), prepared from developing and mature rat forebrain by hypo-osmotic treatment of microsome (microsomal-fraction)-free myelin, appears to be closely related to the myelin-like fraction. Fraction SN 4 shows 2':3'-cyclic nucleotide 3'-phosphohydrolase activity higher than that of the parent myelin. Electrophoresis reveals a multitude of bands with the Wolfgram protein as the main component.

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“…In the spinal cord the small basic-protein peak as measured by Coomassie Blue staining surpasses that of the proteolipid peak at about 25 days and remains high thereafter. This is in keeping with the observations of others, that the proportion of proteolipid protein is less in spinal-cord myelin than in myelin from other areas of the central nervous system (Morell et al, 1973;Lees & Paxman, 1974;Zgorzalewicz et at., 1974;Smith & Sedgewick, 1975). The data on the accumulation of 2':3'-cyclic nucleotide 3'-phosphohydrolase activity presented in the present study and in other previous studies shows a close association between the appearance of this enzyme and myelination (Kurihara & Tsukada, 1968;Banik & Davison, 1969;Olafson et al, 1969;Banik et at., 1974;Sabri et al, 1974;Fishman et at., 1975).…”

Section: Discussionsupporting

confidence: 92%

“…The myelin fraction isolated from early stages of developing central nervous system contained a com- paratively large amount of Wolfgram protein (Wolfgramn, 1966), particularly in myclin from cerebral hemisphere and thalamic area, regions in which myelin appears latest. Similar observations have been made on myelin isolated from developing brains of different species Einstein et al, 1970;Greenfield et al, 1971;Morell et aLt, 1972;Savolainen et al, 1972;Adams & Osborn, 1973;Zgorzalewicz et al, 1974;Banik et al, 1974;Fishman et al, 1975;Sabri et al, 1975). The appearance of myelin in spinal cord from 2-day-old rats has been demonstrated previously (Waksman, 1959;:Kornguth et al, 1966), and the presence of a rnyolinspocific protein shown in this study in 3-day-old rat spinal cord suggests that this myelin shows some charateristics of mature myelin.…”

Section: Discussionsupporting

confidence: 74%

Protein determinants of myelination in different regions of developing rat central nervous system

1977

Biochemical Journal

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Measurements of several different protein determinants correlated with the time and rate ofmyelination in five areas of the central nervous system are pre*ented. The deposition of protein in the subcellular fraction corresponding to the density of adult myelin, the appearance of basic protein characteristic of myelin, the change in proportions of the individual myelin proteins, the appearance and distribution of the myelin marker 2':3'cyclic nucleotide 3'-phosphohydrolase, and the results ofmorphological studies ofpurified myelin axe compared. According to these various criteria, and in agreement with the morphological observations of others, myelin appears earliest in the spinal cord, then in the brain stem, and latest in the cerebral hemispheres. Multilamellarmyelin was observed in the rat brain stem and spinal cord as early as 5 days ofage. The relative proportion ofthe individual myelin proteins changed with myelin maturation in all areas, with the larger basic protein decreasing reciprocally with increase of the smaller basic protein. The proportion of Wolfgram protein also decreased with maturation. Larger proportions of the enzyme 2':3'-cyclic nucleotide 3'-phosphohydrolase were located in the microsomal fraction at early ages. During development the enzyme activity gradually became associated more with a fraction of a density corresponding to adult myelin, suggesting the presence of precursor membrane fragments in microsomal fractions in the early stages of myelination before compact myelin formation. A significant proportion of the total nucleotide phosphohydrolase activity of the homogenate could not be recovered in subcellular fraction at early ages, but the recoveries of the enzyme increased with maturation and the activity was found more in the myelin fraction. Histological examination of the developing central nervous system shows that the onset of myelin deposition occurs at different times in different regions of the central nervous system. Generaily the phylogenetically older parts of the nervous system, irrespective of species, form myelin earlier than the anterior areas. Thus myelin appears in the spinal cord first, then in the brain stem, cerebellum and forebrain. During development, biochemical changes in protein and lipid composition have been observed in myelin isolated from whole brain (

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Ontogenetic Changes in Myelin Protein Composition in Different Regions of Rat Central Nervous System

Cited by 4 publications

References 0 publications

Development and maturation of central nervous system myelin: Comparison of immunohistochemical localization of proteolipid protein and basic protein in myelin and oligodendrocytes

Development and maturation of central nervous system myelin: Comparison of immunohistochemical localization of proteolipid protein and basic protein in myelin and oligodendrocytes

Ontogenetic study of a myelin-derived fraction with 2′:3′-cyclic nucleotide 3′-phosphodydrolase activity higher than that of myelin

Protein determinants of myelination in different regions of developing rat central nervous system

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