Ribonucleoprotein particles derived from the lampbrush chromosomes of newt oocytes

Sommerville, John

doi:10.1016/0022-2836(73)90470-1

Cited by 60 publications

(20 citation statements)

References 29 publications

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“…A nuclear RNP fraction was isolated from ovaries of Triturus cristatus as described previously [19,24]. Basically the oocytes were ruptured gently by using a hand homogenizer and the RNP aggregates were collected by differential centrifugation.…”

Section: Isolation Of Oocyte Nuclear R N P Aggregatesmentioning

confidence: 99%

“…The RNP material was further purified by centrifugation through dense sucrose gradients in which a tight band was formed at a density of 1.18 g/cm3. The density peak contains hnRNP derived from the nucleoplasm and probably also from the loops of the lampbrush chromosomes [19]. Its molecular constituents comprise most of the rapidly labelled RNA of the oocytes together with about 30 times its mass of protein [19].…”

Section: Isolation Of Oocyte Nuclear R N P Aggregatesmentioning

confidence: 99%

“…The density peak contains hnRNP derived from the nucleoplasm and probably also from the loops of the lampbrush chromosomes [19]. Its molecular constituents comprise most of the rapidly labelled RNA of the oocytes together with about 30 times its mass of protein [19]. The RNP aggregates contain no detectable ribosomal RNA or cytoplasmic mRNA.…”

Section: Isolation Of Oocyte Nuclear R N P Aggregatesmentioning

confidence: 99%

“…The amphibian oocyte R N P fraction is similar to the hnRNA from other cells in that the RNA is of high and heterogeneous molecular weight and contains mRNA sequences [22] and in that its association with protein generates linear chains of 20-30-nm particles [23]. Nevertheless the oocyte RNP is unusual in two major respects: most of it isolates as very rapidly sedimenting (> 1500 S) aggregates, and it has an unexpectedly low density of 1.18 g/cm3 in sucrose gradients [19,24]. These observations suggest that the RNP that is released from oocyte nuclei by gentle rupture exists in a highly aggregated state and contains a relatively high proportion of protein.…”

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confidence: 99%

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Interaction of the hnRNA of Amphibian Oocytes with Fibril‐Forming Proteins

Kloetzel

Johnson

Sommerville

1982

European Journal of Biochemistry

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A ribonucleoprotein fraction that contains most of the rapidly labelled hnRNA has been isolated from gently ruptured oocytes of Triturus cristatus. This fraction consists of large aggregates of ribonucleoprotein and has a high (30:1) ratio of protein to RNA. The labelled RNA is contained in ribonucleoprotein particles that have a density of 1.27 g/cm3 in Cs2SO4 gradients (1.39 g/cm3 after formaldehyde fixation in CsCl gradients). Evidence is presented that the particles are associated in vivo with a librillar protein network. When the ribonucleoprotein aggregates are treated with ribonuclease, high salt concentration and nonionic detergent, a fibrillar protein residue is produced which contains many species of protein but a few that have electrophoretic characteristics that are identical to major ribonucleoprotein particle proteins. Isolated labelled hnRNA has been shown to bind specifically polypeptides of molecular weight 60000 and 54000 that are found in both particle and fibril preparations. In binding assays in vitro, these polypeptides are found to interact with mRNA to a lesser extent and not with rRNA. The isolated 60000‐Mr and 54000‐Mr proteins have the dual ability of forming ribonucleoprotein ‘particles’ with hnRNA and of polymerizing to generate 10‐nm fibrillar structures in the absence of RNA. The possible cellular functions of these proteins are discussed.

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Section: Isolation Of Oocyte Nuclear R N P Aggregatesmentioning

confidence: 99%

Section: Isolation Of Oocyte Nuclear R N P Aggregatesmentioning

confidence: 99%

Section: Isolation Of Oocyte Nuclear R N P Aggregatesmentioning

confidence: 99%

mentioning

confidence: 99%

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Interaction of the hnRNA of Amphibian Oocytes with Fibril‐Forming Proteins

Kloetzel

Johnson

Sommerville

1982

European Journal of Biochemistry

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“…The powder was suspended in cold TKM buffer (0.05 M Tris, pH = 7.4, 0.025 M KCI, and 0.005 M MgClz) with 0.25 M sucrose and 0.007 M 2-mercaptoethanol. Fresh oocytes were gently ruptured in the same medium with three strokes of a hand-driven glass homogenizer, as described by Sommerville (37). After being filtered through six layers of cheesecloth, the homogenate was centrifuged for 15 min at 12,000 g (4~ To obtain 4S and 5S RNA, sodium dodecyl sulfate to a final concentration of 0.5% was added to the supernate, and the mixture was repeatedly extracted with an equal volume of water-saturated redistilled phenol.…”

Section: Isolation Of R Namentioning

confidence: 99%

Molecular hybridization of iodinated 4S, 5S, and 18S + 28S RNA to salamander chromosomes.

León¹

1976

The Journal of Cell Biology

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4S, 5S, and 18S + 28S RNA from the newt Taricha granulosa granulosa were iodinated in vitro with carrier-free 125I and hybridized to the denatured chromosomes of Taricha granulosa and Batrachoseps wrighti. Iodinated 18S + 28S RNA hybridizes to the telomeric region on the shorter arm of chromosome 2 and close to the centromere on the shorter arm of chromosome 9 from T. granulosa. On this same salamander the label produced by the 5S RNA is located close to or on the centromere of chromosome 7 and the iodinated 4S RNA labels the distal end of the longer arm of chromosome 5. On the chromosomes of B. wrighti, 18S + 28S RNA hybridizes close to the centromeric region on the longer arm of the largest chromosome. Two centromeric sites are hybridized by the iodinated 5S RNA. After hybridization with iodinated 4S RNA, label is found near the end of the shorter arm of chromosome 3. It is concluded that both ribosomal and transfer RNA genes are clustered in the genome of these two salamanders.

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