Interaction of Nucleosides and Related Compounds With Nucleic Acids as Indicated by the Change of Helix-Coil Transition Temperature

Ts’o, Paul O. P.; Helmkamp, George K.; Sander, Christian

doi:10.1073/pnas.48.4.686

Cited by 119 publications

(30 citation statements)

References 21 publications

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“…Nuclear RNA has a high tendency to form aggregates and to remain aggregated after being nicked if rigorous denaturing conditions are not employed [14,36,37]. Careful studies by Ts'o and his coworkers [38,39] and recently by Pinder et al [40,41] and Spohr et al [42] have shown that formamide used under the proper conditions is an effective denaturant of RNA. We chose to fractionate nuclear RNA according to size by sedimentation at 22 "C in sucrose gradients containing 75 % formamide and no salt.…”

Section: Size Fractionation Of Steady-state Nuclear Rnamentioning

confidence: 99%

Size Distribution of Rat Liver Nuclear RNA Containing mRNA Sequences

Sippel

Groner

Hynes

et al. 1977

European Journal of Biochemistry

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Total rat liver poly(A)-containing polysomal mRNA was size-fractionated on polyacrylamide gels in 98 % formamide. Complementary DNA (cDNA) was prepared from the 8 -14-S mRNA fraction and separated into sequences representing abundant and non-abundant mRNAs. The cDNA complementary to the abundant small mRNA of the rat liver cell (approximately 20 species) was hybridized to nuclear RNA of different lengths to determine the size distribution of nuclear RNA molecules which contain these messenger sequences. It was found that :1. All abundant 8 -14 -S poly(A)-containing mRNAs have larger nuclear precursor molecules ; 20% of the different messenger sequences are found in nuclear RNA of several times their cytoplasmic length.2. 70 % of the mass of the examined nuclear messenger sequences is in RNA molecules of a size similar to their polysomal mRNA; 30% are in larger than 18-S RNA and 2% are between 37 S and 44 S.3 . The majority of small messenger-containing RNA molecules in the RNA prepared from isolated nuclei are of true nuclear origin, since their frequency distribution differs significantly from that of the polysomal 8 -14-S mRNA.To understand the regulation of gene expression in eucaryotic cells it is crucial to know more about nuclear processes involved in the biogenesis of mRNA. Several features of the synthesis and structure of hnRNA indicate its role in mRNA metabolism (for review see [l-51). Indirect evidence first led to the postulate that hnRNA contained precursor molecules to mRNA [6,7]. Hybridization-competition experiments later demonstrated base-sequence homology between polyribosomal mRNA and hnRNA from HeLa cells [8]. Furthermore, it was found that viral-specific RNAs in and polyoma-infected [lo] cells are transcribed as giant RNA molecules. However, owing to the enormous sequence complexity, the large size and the high turnover of hnRNA, a detailed describtion of the nuclear pathway of messenger sequences has not yet Abbreviations. Hepes. 4-(2-hydroxyethyl)-l-piperazineethanesulfonic acid; AMV, avian myeloblastosis virus; cDNA, DNA copy complementary to mRNA ; hnRNA, polydisperse high-molecularweight nuclear RNA; rot value, concentration of RNA (as mol phosphate/l) times time of hybridization (in s); rotllz value, rot value at which half the hybridizable cDNA is hybridized; vgt value, RNA derived from the amount of liver tissue (g), hybridized in IO-pI assay volume, times the hybridization time (h).Enzyme. S 1 nuclease, single-strand-specific endonuclease from Aspergillus oryzae (EC 3.1.4.21).been possible. The use of molecular hybridization with complementary DNA copies of specific mRNA molecules to identify messenger sequences in steadystate nuclear RNA has resulted in an increased amount of new information, but no general picture has emerged from these studies. For example, larger nuclear precursor RNA molecules for globin mRNA have been found, although with conflicting results as to their largest size [ l l -171. For the case of ovalbumin mRNA, no larger nuclear RNA containing the messenger se...

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Section: Size Fractionation Of Steady-state Nuclear Rnamentioning

confidence: 99%

Size Distribution of Rat Liver Nuclear RNA Containing mRNA Sequences

Sippel

Groner

Hynes

et al. 1977

European Journal of Biochemistry

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“…It is reported in the literature (e.g. Ts'o, Helmkamp & Sander, 1962), that the T, value is proportional to the logarithm of the ionic strength of the solvent and that, with SSC solvent, the pH value does not influence the T, value within the range pH 5.5-8.5. Two sets of solutions were prepared ( Table 2) to determine the effect on T, value of changing ionic strength (pH constant) and of changing pH value in a region of an ionic strength lower than that of SSC solvent (molarity being constant).…”

Section: Introductionmentioning

confidence: 97%

The Base Composition of Deoxyribonucleic Acids of Streptomyces

Frontali

Hill

Silvestri

1965

Journal of General Microbiology

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SUMMARYThe base composition of DNA preparations from 12 strains of Streptomyces and 1 strain of Nocardia were determined from their denaturation temperature (T,) and buoyant density.The yo GC (guanine+cytosine) contents ranged from 74.4 to 78.5 (from T,) and from 69.4 to 73.4 (from buoyant density). The correlation between the two sets of data and the found differences are discussed. The range of pH values which did not affect T, and the degree of hyperchromic effect have been related to the ionic strength of the solvent. With 0.01 M-phosphate as solvent the pH indifference range was narrower and the hyperchromic effect smaller than with 0.2 M-Na' solvent.Though the difference between the maximum and minimum : ( , GC in Streptomyces is sufficient to distinguish the respective strains, within the extreme values there is a continuous progression of base composition which does not permit taxonomic divisions to be made on the basis of overall yo GC alone.

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“…High concentrations of certain electrolytes, including sodium perchlorate and trichloroacetates (1), as well as various neutral molecules, including formamide (2), dimethyl sulfoxide (3), and urea (4), lower the melting temperature of duplex DNA and therefore the optimum temperature for DNA:DNA reassociation (5,6). This is advantageous because, in general as the reaction temperature is lowered, the amount of chain scission occurring during the time needed for association reactions of complementary strands is reduced.…”

Section: Introductionmentioning

confidence: 99%