Nuclear Polyanions as De-Repressors of Synthesis of Ribonucleic Acid

Frenster, John H.

doi:10.1038/206680a0

Cited by 294 publications

(47 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Various interactions between histones and the glycosaminoglycans in the nuclei and those on the cell surface have been described (8,9,17,76,79). Such findings, in combination with our data, suggest that histone H1 may directly bind cell surface heparan sulfate and consequently block the binding of NV to the cell surface.…”

Section: Discussionsupporting

confidence: 74%

Genogroup II Noroviruses Efficiently Bind to Heparan Sulfate Proteoglycan Associated with the Cellular Membrane

Tamura

Natori

Kobayashi

et al. 2004

J Virol

View full text Add to dashboard Cite

Norovirus (NV), a member of the family Caliciviridae, is one of the important causative agents of acute gastroenteritis. In the present study, we found that virus-like particles (VLPs) derived from genogroup II (GII) NV were bound to cell surface heparan sulfate proteoglycan. Interestingly, the VLPs derived from GII were more than ten times likelier to bind to cells than were those derived from genogroup I (GI). Heparin, a sulfated glycosaminoglycan, and suramin, a highly sulfated derivative of urea, efficiently blocked VLP binding to mammalian cell surfaces. The reagents known to bind to cell surface heparan sulfate, as well as the enzymes that specifically digest heparan sulfate, markedly reduced VLP binding to the cells. Treatment of the cells with chlorate revealed that sulfation of heparan sulfate plays an important role in the NV-heparan sulfate interaction.

show abstract

Section: Discussionsupporting

confidence: 74%

Genogroup II Noroviruses Efficiently Bind to Heparan Sulfate Proteoglycan Associated with the Cellular Membrane

Tamura

Natori

Kobayashi

et al. 2004

J Virol

View full text Add to dashboard Cite

show abstract

“…In all cases, template active chromatin has been separated to some extent from template repressed chromatin. Differences in transcriptional properties (2,5,10), DNA:protein content and interactions (5-8, 10, 11), chromosomal RNA (12,13), and DNA sequences (3,4,14,15) have been reported. Many of these studies have involved the isolation of transcribable regions comprising 20% or more of the genome and, in some cases, fractionation techniques provided only a continuous spectrum of chromatin rather than two discrete fractions.…”

mentioning

confidence: 99%

Chemical and physical properties of fractionated chromatin.

Berkowitz¹,

Doty²

1975

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

View full text Add to dashboard Cite

Sonicated chicken reticulocyte chromatin was fractionated into transcriptionally active and transcriptionally repressed components. The active fraction is 8% of the whole chromatin but contains 70% of the newly synthesized chromosomal RNA. This RNA has five times as many hemoglobin RNA sequences as does the RNA in the repressed fraction. The amount of the active fraction in the chromatins of several tissues correlates with their synthetic activity. The molecular weight of the DNA of the repressed fraction is approximately twice that of the active fraction. Moreover, the configuration of repressed chromatin is much more compact, consistent with a much larger sedimentation constant. The transcriptionally active fraction displays a 60 lower melting profile and is highly susceptible to DNase I relative to the repressed fraction. The active fraction contains twice as much non-histone protein and 15% less histone than the repressed fraction and is lacking the lysine-rich and much of tie arginine-rich histones. The fraction of eukaryotic chromatin which is transcriptionally active comprises only a small part of the total genome (1). It is advantageous, therefore, to be able to separate this material from the remainder of the chromatin and to identify how it differs from the much larger part that is transcriptionally inactive. For work in this direction we have chosen 12-day chick embryo reticulocyte chromatin for study, since it is actively transcribing hemoglobin messenger RNA and since it has a transcribable region which comprises a particularly small percentage of the genome and therefore produces a comparatively limited variety of mRNA molecules.Various techniques have been used to fractionate chromatin. The essential break-up of the native chromatin has been accomplished by shearing (2-5), sonication (6), DNase digestion (7), or pressure (5, 8) and the chromatin fragments have been fractionated by differential centrifugation (9), sucrose gradient centrifugation (2, 3, 5), solubility (7), and ion exchange (6) or hydroxyapatite (4) We have sought to obtain a clearer separation of transcriptionally active chromatin (TC) and inactive, repressed chromatin (RC) so that the differences might be more unambiguously assessed. This has been done by combining several fractionation and separation techniques in order to maximize efficient and reproducible separation of a small, discrete portion of the chromatin with transcriptional activity (16). This fraction shows more striking differences in both chemical and physical properties when compared to the remainder of the genome than has generally been reported. MATERIALS AND METHODSChromatin Fractionation and Separation. Blood was collected from 12-day-old chick embryos. The cells were washed in Solution 1 [0.32 M sucrose, 2 mM MgCl2, 1 mM potassium phosphate (pH 6.8)] and then lysed in 10 mM CaCl2. The nuclei were washed in a Dounce homogenizer with a solution containing 0.32 M sucrose, 1 mM MgC12, 1 mM potassium phosphate (pH 6.8), and 0.3% Triton N-101. Nuclei were st...

show abstract

“…2). The observed effect might be a response to a gradual decrease in water content in the nucleus or to a loss of nuclear non-histone proteins which seem to influence both nuclear volume (ALFERT 1952) and DNA activation (FRENSTER 1965;PAUL and MALCOM 1976;PEDERSON 1974aPEDERSON , 1974b. We might, however, also think that some changes in nuclear DNA bound histones might be responsible for the reduced nuclear volume.…”

Section: Results and Conclusionmentioning

confidence: 99%