Partial enzyme digestion studies onescherichia coli,pseudomonas, chlorella,drosophila, HeLa and yeast 5S RNAs support a general class of 5S RNA models

Summary Fox and Woese (1975a) have shown that a model of 5S RNA secondary structure similar to the one originally derived forChlorella 5S RNA can be generalized with relatively minor variations to all sequenced 5S RNA molecules, i.e. that corresponding base paired regions can be formed at approximately the same positions. We present experimental data in favour of this hypothesis and show that the points at which ribonucleases T1, T2 and pancreatic ribonuclease cleave six different 5S RNA molecules under mild conditions (high ionic strength, low temperature, low RNAase concentration) nearly always fall in the proposed single-stranded regions. We conclude that this model is a good approximation to the conformation of 5S RNA in solution.     

Distribution of NG, NG-dimethylarginine in nuclear protein fractions

Nuclear proteins have been fractionated into five distinct classes according to their extractability from rat liver nuclei at different pH and salt concentrations. The fractions have been analyzed for their amino acid composition which shows the presence of N^G, N^G-dimethylarginine, in sizable amount, in non-histone nuclear proteins (NHNP). This modification is most prominent in proteins which are found associated with rapidly-labeled heterogeneous RNA (HnRNP proteins).     

Effect of rye embryo ribosome nuclease on double-stranded RNA

In extracts obtained by treating rye embryo ribosomes with 0.5 M NH₄Cl, nuclease activity was noted towards double-stranded RNA from virus of Penicillium chrysogenum and towards synthetic poly (A)-poly (U) and poly (I)-poly (C) complexes.     

Cell free synthesis of some storage protein subunits by polyribosomes and RNA isolated from developing seeds of pea (Pisum sativum L.)

Polyribosomes which have template activity in the wheat germ system have been isolated from developing pea seeds. Some of the translation products have identical mobilities to the vicilin and legumin subunits by SDS-PAGE. Certain products were specifically immunoprecipitated with antisera prepared against purified vicilin and legumin fractions. Various RNA fractions including poly A-rich RNA have also been isolated from polyribosomes and shown to direct the synthesis of polyripeptides whose properties are similar to the storage protein subunits. The results are discussed in relationship to other investigations with seed storage protein biosynthesis in vitro.Abbreviations DTT dithiothreitol - SDS-PAGE SDS-polyacrylamide gel electrophoresis - TCA tricarboxylic acid     

The use of Taka-diastase in a[3H]poly(A) hybridization assay of oligo(U) sequences in RNA

A reliable assay of uridylate sequences longer than 10 is described. The procedure is based on the hybridization of [3H]poly(A) with poly(U) or oligo(U) sequences in high ionic conditions and a subsequent degradation of single stranded polynucleotides with purified Taka-diastase. A 1:2 complex between poly(A) and poly(U) is formed on which on poly(U) strand is digested by Taka-diastase. The procedure is especially suitable for the detection and quantitation of Un (n greater than 10) in RNA preparation.     

Early metabolic changes in regenerating microfragments of the liverwort Riella helicophylla (Bory et Mont.) Mont.: Protein and RNA synthesis,free α-amino concentration

Microfragments of constant size were isolated from the thallus of Riella by a rapid punching procedure. Thus it was possible to study various metabolic parameters especially during the first hours after fragment isolation. Protein synthesis increases rapidly after a slight decrease at 30 min. The earliest significant increase in RNA synthesis occurs at 8 h, indicating a different activation pattern. The concentration of -amino compounds drops at 30 min and then increases continuously, thus exhibiting a close relationship with the measured alterations in protein synthesis. Another indication of metabolic conversions during regeneration is provided by the changing level of free radioactive leucine, which shows a marked turning point at 24 h after fragmentation. Analysis of free -amino concentrations in small regions of larger fragments also indicates the establishment of new intercellular correlations only a few hours after isolation of the cells from the meristem. Up to the 8th h after fragmentation, the contents of both the adaxial and peripheral fragment regions increase. Thereafter only the adaxial (regenerating) cells continue accumulating; the peripheral (nonregenerating) ones remain at the same level.