Partial Characterization of a New Myelin Protein Component

Agrawal, Harish C.; Burton, Robert M.; Fishman, Marvin A.; Mitchell, R. F.; Prensky, Arthur L.

doi:10.1111/j.1471-4159.1972.tb05118.x

Cited by 217 publications

(88 citation statements)

References 24 publications

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“…These studies indicated the homogeneity and purity of our samples. The electrophoretic profiles were similar to those reported by Agrawal et al (1972) except that the DM-20 band was not detectable in our myelin preparations. Only faint bands corresponding to basic protein and proteolipid protein were detectable in the myelinlike preparation (Plate 3).…”

Section: Characterization Ofmyelin and Myelin-likefractionssupporting

confidence: 88%

“…Disc-gel electrophoresis in sodium dodecyl sulphate was carried out essentially as described by Agrawal et al (1972 washed three times with water by centrifugation and all the supernatants were combined, dialysed at 2°C against 0.1 M-acetic acid for 2 days and freezedried. Proteolipid protein and high-molecular-weight (Wolfgram, 1966) protein.…”

Section: Other Methodsmentioning

confidence: 99%

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Turnover of myelin and other structural proteins in the developing rat brain

Sabri

Bone

Davison

1974

Biochemical Journal

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1. Protein metabolism of myelin and other subcellular components from developing rat brain was studied for periods from 5h to 210 days after intraperitoneal injection of [3H]-lysine and ['4C]glucose. 2. Half-lives for total brain proteins (t0.5) were 27 days after [3H]lysine and 4 days after ['4C]glucose injection. 3. Factors accounting for the difference in the turnover rates obtained with different precursors, and the problem of reutilization of the label were investigated. 4. The catabolism of purified myelin proteins was studied and the half-lives of individual myelin proteins were calculated. 5. Myelin basic proteins turned over at two different rates. Half-life of the fast component of myelin basic proteins was 19-22 days and the slow component exhibited a high degree of metabolic stability. 6. Proteolipid protein underwent slow turnover. High-molecular-weight Wolfgram (1966) proteins underwent (relatively) fast metabolism (tO.5 of 17-22 days).Although early workers (Furst et al., 1958;Davison, 1961) concluded that white-matter and myelin-sheath proteins were metabolically stable, this view has been widely challenged (Smith, 1972;D'Monte et al., 1971;Wood & King;1971

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Section: Characterization Ofmyelin and Myelin-likefractionssupporting

confidence: 88%

Section: Other Methodsmentioning

confidence: 99%

Turnover of myelin and other structural proteins in the developing rat brain

Sabri

Bone

Davison

1974

Biochemical Journal

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“…They are translated from four different mRNAs (50), and the four MBP mRNAs can be produced from a single MBP gene by alternative mRNA splicing (12,44). Two PLPs are present in myelin, the major PLP, which has an apparent molecular weight of 25,000, and the closely related proteolipid DM20 (1), which has an apparent molecular weight of 20,000. PLP and DM20 may have a relationship similar to that found among the four MBPs, since they have identical amino-and carboxyl-terminal sequences (46), and they are very closely related by amino acid composition and by antigenic characteristics.…”

mentioning

confidence: 99%

Characterization of myelin proteolipid mRNAs in normal and jimpy mice.

Gardinier¹,

Macklin²,

Diniak³

et al. 1986

Mol. Cell. Biol.

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A clone specific for the rat myelin proteolipid protein (PLP) was isolated from a cDNA library made in pUC18 from 17-day-old rat brain stem mRNA. This clone corresponded to the carboxyl-terminal third of the PLP-coding region. The clone was used to identify PLP-specific mRNAs in mouse brain and to establish the time course of PLP mRNA expression during mouse brain development. Three PLP-specific mRNAs were seen, approximately 1,500, 2,400, and 3,200 bases in length, of which the largest was the most abundant. During brain development, the maximal period of PLP mRNA expression was from 14 to 25 days of age, and this was a similar time course to that for myelin basic protein mRNA expression. When the jimpy mouse, an X-linked dysmyelination mutant, was studied for PLP mRNA expression, low levels of PLP mRNA were seen which were approximately 5% of wild-type levels at 20 days of age. When jimpy brain RNA was analyzed by Northern blotting, the PLP-specific mRNA was shown to be 100 to 200 bases shorter than the wild-type PLP-specific mRNA. This size difference was seen in the two major PLP mRNAs, and it did not result from a loss of polyadenylation of these mRNAs.The biosynthesis of the myelin sheath is a crucial part of nervous system development, and as a result, the developmental expression of the myelin protein genes is highly regulated. The normal pattern of myelin protein expression in rodents indicates that little myelin protein expression occurs prenatally or in neonatal animals (2,5,6,8,23,26,28) and that myelin protein synthesis and accumulation increase significantly in the brain at about 10 days after birth, reaching a peak between 15 and 22 days after birth (2,5,6,8,23).Central nervous system myelin contains two major classes of proteins, myelin basic protein (MBP) and proteolipid protein (PLP), which together constitute as much as 80% of the total myelin protein (15,30). The four MBPs that are present in rodent myelin have homologous amino acid sequences, including identical amino-and carboxyl-terminal sequences but internal segments of unique amino acid sequence (3). They are translated from four different mRNAs (50), and the four MBP mRNAs can be produced from a single MBP gene by alternative mRNA splicing (12,44). Two PLPs are present in myelin, the major PLP, which has an apparent molecular weight of 25,000, and the closely related proteolipid DM20 (1), which has an apparent molecular weight of 20,000. PLP and DM20 may have a relationship similar to that found among the four MBPs, since they have identical amino-and carboxyl-terminal sequences (46), and they are very closely related by amino acid composition and by antigenic characteristics. The expression of these myelin proteins correlates closely with the formation of myelin in the developing rat brain, and mouse mutants that are defective in myelin formation show lowered levels of these myelin proteins (4,14,20,25 expression and the genetic deficiency in the shiverer mouse myelination mutant (12,34,44). Several groups have recently isolated cDNA ...

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“…The paradox regarding the proteolipid nature of MBP is widely known but largely ignored (Agrawal et al, 1972; (Table III), has physical significance.…”

Section: Discussionmentioning

confidence: 99%