Wheat-Embryo Ribonucleates. IV. Factors That Influence the Formation and Stability of a Complex Between 5S rRNA and 18S rRNA

1975 ◽  
Vol 53 (3) ◽  
pp. 320-327 ◽  
Author(s):  
A. A. Azad ◽  
B. G. Lane
Keyword(s):  
18S Rrna ◽  
5S Rrna ◽  
23S Rrna ◽  
Wheat Embryo ◽  
Physiological Importance ◽  
5.8S Rrna ◽  
Wheat Embryos ◽  
The Subject ◽  
26S Rrna ◽  
Source Materials

Under the conditions used in this study, wheat-embryo 5S rRNA complexes with its homologous 18S rRNA from wheat embryos and with heterologous 18S rRNA from other eukaryotic source materials such as yeast, L cells, and HeLa cells, but it does not complex with heterologous 16S rRNA from a prokaryote such as Escherichia coli or with homologous or heterologous 26S(23S) rRNA of either eukaryotic or prokaryotic origin.If a solution of wheat-embryo rRNA is simply made 0.3 M with respect to NaCl and then heated at 60 °C for 3 min before quick cooling to room temperature (ca. 20 °C), there is both preferential and efficient complex formation between 5S and 18S rRNA and between 5.8S and 26S rRNA.The laboratory-prepared' complex between wheat-embryo 5S rRNA and its homologous 18S rRNA is more thermostable in 0.1 M NaCl solution than is the 'natural' complex between wheat-embryo 5.8S rRNA and its homologous 26S rRNA, and both complexes 'melt' over a narrow range of temperature.The possible physicochemical and physiological importance of both homologous and heterologous rRNA complexes is the subject of a brief discussion.

Hypermodified alkali-stable dinucleotide sequences in each of the high-molecular-weight (26S and 18S) ribosomal RNA species of wheat

1977 ◽  
Vol 55 (5) ◽  
pp. 582-586 ◽  
Author(s):  
M. W. Gray ◽  
R. S. Cunningham
Keyword(s):  
Molecular Weight ◽  
Ribosomal Rna ◽  
18S Rrna ◽  
28S Rrna ◽  
Animal Cells ◽  
Wheat Embryo ◽  
Rrna Species ◽  
Wheat Embryos ◽  
The Individual ◽  
26S Rrna

Two hypermodified, alkali-stable dinucleotide sequences, each containing abase modification in addition to sugar methylation, are known to be present in wheat embryo 26S + 18S rRNA (Gray, M. W. (1974) Biochemistry 13, 5453–5463). Quantitative analysis of unfractionated 26S + 18S rRNA had suggested that each of these sequences (Cm-ψp and ψm-Ap, where Cm = O2′-methylcytidine and ψm = O2′-methylpseudouridine) was present in either the 18S or the 26S rRNA species, but not in both, at a frequency of not more than once per chain. In the study reported here, the individual 32P-labeled 18S and 26S rRNA species were isolated from viable wheat embryos germinated in the presence of [32P]orthophosphate. From analyses of phosphodiesterase and alkaline hydrolysates of the separated [32P]RNAs, we conclude that ψm-Ap is confined to wheat cytosol 18S rRNA, whereas Cm-ψp is localized in wheat cytosol 26S rRNA. The presence of ψm in the 18S rRNA of wheat stands in contrast with the situation in animal cells, where this hypermodified nucleoside is located in the 28S rRNA (Khan, M. S. N. &Maden, B. E. H. (1976) J. Mol. Biol. 101, 235–254)

Wheat embryo ribonucleates. VII. Rapid, efficient and selective formation of 5S–18S and 5.8S–26S hybrids in an aqueous solution of the four ribosomal polynucleotides, and the results of a search for the corresponding hybrids in wheat embryo ribosomes

1977 ◽  
Vol 55 (1) ◽  
pp. 99-109 ◽  
Author(s):  
K. M. Oakden ◽  
A. A. Azad ◽  
B. G. Lane
Keyword(s):  
Aqueous Solution ◽  
Wheat Germ ◽  
18S Rrna ◽  
Sodium Dodecyl ◽  
Globin Mrna ◽  
Wheat Embryo ◽  
5.8S Rrna ◽  
Free Translation ◽  
26S Rrna ◽  
Selective Formation

(1) If wheat embryo 5S and 5.8S rRNA are differentially labelled, it can be shown that there is highly selective association of 5S [14C]RNA with 18S rRNA, and of 5.8S [3H]RNA with 26S rRNA when a solution (0.3 M NaCl) that contains approximately equimolar amounts of the four ribosomal polynucleotides is heated briefly (3 min) at 60 °C.(2) Comparison of Tm values and melting profiles for laboratory-prepared and natural 5.8S–26S rRNA hybrids suggests that restoration of the natural union between 5.8S and 26S rRNA can be achieved with facility and fidelity in the laboratory.(3) Union between 5.8S and 26S rRNA remains intact when wheat embryo ribosomes are disintegrated either by digestion with pronase or by treatment with sodium dodecyl sulphate, but the same treatments release 5S and 18S rRNA as freely migrating electrophoretic components.(4) Intact 18S and 26S rRNA can be prepared from small and large subunits, respectively, when wheat embryo ribosomes are dissociated by treatment with 0.5 M KCl.(5) Incidental to the principal investigation, it has been shown that, even after storage for more than 6 years at − 70 °C, commercial supplies of roller-milled wheat germ yield S23 extracts that are very active in the cell-free translation of globin mRNA.(6) The physicochemical and possible biochemical significance of various types of intermolecular complexing between pairs of ribosomal polynucleotides is a subject of discussion.

Wheat-embryo ribonucleates. XV. Characterization of a fraction of RNA subject to conspicuous terminal labeling during early germination of wheat embryos

1984 ◽  
Vol 62 (6) ◽  
pp. 321-328 ◽  
Author(s):  
Theresa D. Kennedy ◽  
Byron G. Lane
Keyword(s):  
Amino Acids ◽  
Gel Filtration ◽  
Isotopic Labeling ◽  
Developmentally Regulated ◽  
Wheat Embryo ◽  
Physiological Importance ◽  
5.8S Rrna ◽  
Early Germination ◽  
Wheat Embryos

Various techniques have been used to characterize the rapidly migrating electrophoretic components (RMEC) in an RNA fraction which is subject to conspicuous terminal labeling (mostly adenosine) when wheat embryos are pulse labeled with 3H-labeled nucleosides during early germination. Detection of terminally labeled RMEC RNA is most favoured during early germination when labeling of 3′-hydroxyl termini in preexisting RNA, catalyzed by RNA nucleotidyltransferases, is greatest in relation to nonterminal labeling of nascent RNA, catalyzed by RNA polymerases. The RMEC RNA is tenaciously associated with a fraction of high-molecular-weight RNA and it can be subdivided and classified into two fractions, RMEC-1 and RMEC-2, by electrophoresis in polyacrylamide, gel filtration through Sephadex, or assay of amino acid acceptance. The RMEC-1 RNA and bulk wheat-embryo tRNA have similar capacities to accept a wide variety of amino acids, but RMEC-2 RNA does not accept any of the amino acids tested. RMEC-2 RNA is broadly heterodisperse and one of its component polynucleotides has been identified by sequence analysis as a tridecanucleotide fragment from the 3′-hydroxyl end of 5.8S rRNA. This study was undertaken as part of a broader program in which isotopic labeling and analysis of nucleates and proteins in germinating wheat embryos have been used to detect signal events and to evaluate their physiological significance. It is concluded that conspicuous terminal labeling of RMEC RNA during early germination of wheat embryos is unlikely to be of physiological importance. However, isotopic labeling and analysis of the nucleates and proteins in germinating embryos has uncovered other signal events which appear to be of physiological importance. Discovery of the existence of a number of developmentally regulated proteins and the way in which discovery of these proteins is expected to direct the course of future investigations in the laboratory are subjects of a brief discussion.

Wheat embryo ribonucleates. VI. Comparison of the 3′-hydroxyl termini in 'rapidly labelled' RNA from metabolizing wheat embryos with the corresponding termini in ribosomal RNA from differentiating embryos of wheat, barley, corn and pea

1976 ◽  
Vol 54 (3) ◽  
pp. 261-271 ◽  
Author(s):  
K. M. Oakden ◽  
B. G. Lane
Keyword(s):  
18S Rrna ◽  
Short Term ◽  
Plant Materials ◽  
Wheat Embryo ◽  
Pea Seedlings ◽  
Wheat Embryos ◽  
26S Rrna ◽  
Hydroxyl Termini ◽  
End Group

The NaCl-insoluble (2.5 M, 0 °C) fraction of wheat embryo RNA (iRNA) can be labelled when wheat embryos are subjected to either short-term (0.5 h) or long-term (24 h) imbibition in a medium that contains tritium-labelled adenosine, guanosine, cytidine and uridine. Electrophoretic analyses reveal that, after short-term labelling, there is a broadly heterodisperse distribution of radioactivity in 'rapidly labelled' i[3H]RNA, but after long-term labelling, there is an essentially trimodal distribution of radioactivity in i[3H]RNA. End-group analyses reveal that, after short-term labelling, adenosine is the principal 3′-hydroxyl terminus in all centrifugal subfractions of 'rapidly labelled' i[3H]RNA, whereas cytidine (in 5.8S rRNA), guanosine (in 18S rRNA) and uridine (in 26S rRNA) are the principal 3′-hydroxyl termini in centrifugal subfractions of wheat embryo i[3H]RNA. Guanosine is also the principal 3′-hydroxyl terminus in the 18S rRNA of differentiating embryos excized from both monocotyledonous (wheat, barley, corn) and dicotyledonous (pea) seedlings. The implications that the end-group measurements may have for current views about the possible biochemical involvements of 3′-hydroxyl terminal sequences in both mRNA and 18S rRNA are subjects of discussion. Incidental to the principal investigation, an existing technique for analyzing the RNA contents of cellular materials has been appropriately modified to circumvent interference from uv-absorbing pigments, which, when present, prevent application of the method to plant materials.

Mouse rDNA: sequences and evolutionary analysis of spacer and mature RNA regions

1983 ◽  
Vol 3 (8) ◽  
pp. 1488-1500
Author(s):  
W E Goldman ◽  
G Goldberg ◽  
L H Bowman ◽  
D Steinmetz ◽  
D Schlessinger
Keyword(s):  
18S Rrna ◽  
23S Rrna ◽  
Homologous Sequence ◽  
28S Rrna ◽  
Evolutionary Analysis ◽  
Sequence Comparisons ◽  
Rdna Sequences ◽  
5.8S Rrna ◽  
Time Required ◽  
Ribosome Formation

Two regions of mouse rDNA were sequenced. One contained the last 323 nucleotides of the external transcribed spacer and the first 595 nucleotides of 18S rRNA; the other spanned the entire internal transcribed spacer and included the 3' end of 18S rRNA, 5.8S rRNA, and the 5' end of 28S rRNA. The mature rRNA sequences are very highly conserved from yeast to mouse (unit evolutionary period, the time required for a 1% divergence of sequence, was 30 X 10(6) to 100 X 10(6) years). In 18S rRNA, at least some of the evolutionary expansion and increase in G + C content is due to a progressive accretion of discrete G + C-rich insertions. Spacer sequence comparisons between mouse and rat rRNA reveal much more extensive and frequent insertions and substitutions of G + C-rich segments. As a result, spacers conserve overall G + C richness but not sequence (UEP, 0.3 X 10(6) years) or specific base-paired stems. Although no stems analogous to those bracketing 16S and 23S rRNA in Escherichia coli pre-rRNA are evident, certain features of the spacer regions flanking eucaryotic mature rRNAs are conserved and could be involved in rRNA processing or ribosome formation. These conserved regions include some short homologous sequence patterns and closely spaced direct repeats.

Wheat embryo ribonucleates. XIV. Mass isolation of mRNA from wheat germ and comparison of its translational capacity with that of mRNA from imbibing wheat embryos

1979 ◽  
Vol 57 (9) ◽  
pp. 1170-1175 ◽  
Author(s):  
A. C. Cuming ◽  
T. D. Kennedy ◽  
B. G. Lane
Keyword(s):  
Wheat Germ ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sucrose Density Gradient ◽  
Wheat Embryo ◽  
Molecular Weights ◽  
Wheat Embryos ◽  
The Subject ◽  
Mass Isolation ◽  
Gradient Fractionation ◽  
Rabbit Reticulocytes

Commercially milled wheat germ is shown to be a convenient source material for facile recovery of mass (milligram) quantities of highly purified poly(A)-rich RNA. This poly(A)-rich RNA is efficiently translated in a nuclease-treated extract of rabbit reticulocytes. By sucrose density gradient fractionation of bulk poly(A)-rich RNA from wheat germ, it has been possible to show that there is a direct relationship between the molecular weights of the polypeptide products of cell-free synthesis and the molecular weights of the wheat mRNA molecules which program their synthesis. As assessed by SDS – polyacrylamide gel electrophoresis, the same array of polypeptides is synthesized when nuclease-treated reticulocyte extract is programmed by poly(A)-rich RNA from either commercially supplied or laboratory-prepared wheat embryos. Significantly, there are gross quantitative if not qualitative differences between the translational capacities of poly(A)-rich RNA from dry and imbibing wheat embryos, and the possible importance of these differences for interpreting a changing pattern of polypeptide synthesis in imbibing wheat embryos is the subject of a brief discussion.

Wheat embryo ribonucleates. VIII. The presence of 7-methylguanosine 'cap structures' in the RNA of imbibing wheat embryos

1977 ◽  
Vol 55 (8) ◽  
pp. 819-824 ◽  
Author(s):  
M. S. Saini ◽  
B. G. Lane
Keyword(s):  
Ribosomal Rna ◽  
Messenger Rna ◽  
Large Fraction ◽  
Deae Cellulose ◽  
Careful Analysis ◽  
Significant Fraction ◽  
Unbound Fraction ◽  
Wheat Embryo ◽  
Wheat Embryos ◽  
The Subject

1. By imbibing wheat embryos in media that contain methyl-labelled methionine, it is possible to label both terminal and nonterminal 7-methylguanosine constituents in NaCl-insoluble (2.5 M, 0 °C) RNA (iRNA).2. Most of the 7-[Me-14C]methylguanosine in wheat embryo i[Me-14C]RNA is present in nonterminal positions of polynucleotide chains, probably in ribosomal RNA.3. By passage through a column of oligo-dT-cellulose, it is possible to show that most of the 7-[Me-3H]methylguanosine in a 'bound' fraction of i[Me-3H]RNA from imbibing wheat embryos is present in terminal 'cap' structures, probably in messenger RNA.4. Although most of the 7-[Me-3H]methylguanosine in the 'unbound' (to oligo-dT-cellulose) fraction of i[Me-3H]RNA was present in nonterminal positions, there was also a highly significant fraction of 7-[Me-3H]methylguanosine in terminal 'cap' structures. Although it will be a subject of continued investigation, possible reasons why a large fraction of the total 7-[Me-3H]-methylguanosine was present in the 'unbound' fraction, in this present study, are a subject of discussion.5. Careful analysis failed to reveal the presence of any N6,O2′-di[Me-3H]methyladenosine in the 'unbound' fraction of i[Me-3H]RNA.6. Factors that might influence the binding of 'cap' oligonucleotides to DEAE-cellulose are the subject of a brief discussion.

scholarly journals 4.5S ribonucleic acid, a novel ribosome component in the chloroplasts of flowering plants

1979 ◽  
Vol 183 (3) ◽  
pp. 605-613 ◽  
Author(s):  
C M Bowman ◽  
T A Dyer
Keyword(s):  
Ribosomal Rna ◽  
Broad Bean ◽  
Large Subunit ◽  
Flowering Plants ◽  
5S Rrna ◽  
23S Rrna ◽  
Low Molecular Weight ◽  
5.8S Rrna ◽  
Wide Range ◽  
Predominant Variant

A species of low-molecular-weight ribosomal RNA, referred to as ‘4.5S rRNA’, was found in addition to 5S rRNA in the large subunit of chloroplast ribosomes of a wide range of flowering plants. It was shown by sequence analysis that several variants of this RNA may occur in a plant. Furthermore, although in most flowering plants the predominant variant contains about 100 nucleotides, in the broad bean it has less than 80. It seems, therefore, to be much more diverse in size and sequence than the other ribosomal RNA species. Like 5S rRNA, it does not contain modified nucleotides and it is also unusual in having an unphosphorylated 5′-end. It is apparently neither a homologue of cytosol 5.8S rRNA nor a fragment of 23S rRNA.

Wheat-Embryo Ribonucleates. I. Subcellular Localization of a Satellite Polyribonucleotide

1973 ◽  
Vol 51 (5) ◽  
pp. 606-612 ◽  
Author(s):  
A. A. Azad ◽  
B. G. Lane
Keyword(s):  
Microsomal Fraction ◽  
Large Subunit ◽  
Satellite Rna ◽  
Selective Precipitation ◽  
Ribosomal Subunits ◽  
Wheat Embryo ◽  
Wheat Embryos ◽  
The Subject ◽  
Rna Complex ◽  
Electrophoretic Component

(1) When wheat embryos are extracted with aqueous phenol and the aqueous phase is made 2.5 M with respect to NaCl at 0 °C, there is selective precipitation of about 80% of the total RNA. The 18 S and 26 S RNA species from the wheat-embryo ribosomes comprise a preponderant mass fraction (ca. 80%) of this NaCl-insoluble RNA (iRNA). A small amount of a rapidly migrating electrophoretic component (iRMEC) can be released by aqueous denaturation of wheat-embryo NaCl-insoluble RNA and because it is specifically complexed with 26 S RNA, the iRMEC component has been termed a "satellite" of 26 S RNA.(2) The wheat-embryo satellite RNA has been shown to be present in the microsomal fraction recovered from cell-free homogenates of wheat embryos.(3) The wheat-embryo satellite RNA has been shown to be differentially localized in the large subunit of wheat-embryo ribosomes where it presumably exists as part of the same intermolecular 26 S RNA complex that can be isolated by directly extracting the whole embryos with aqueous phenol.(4) During preparation of the ribosomal subunits, there is substantial degradation of the component ribonucleates and the nature of this degradation is the subject of a brief discussion.

scholarly journals Mouse rDNA: sequences and evolutionary analysis of spacer and mature RNA regions.

1983 ◽  
Vol 3 (8) ◽  
pp. 1488-1500 ◽  
Author(s):  
W E Goldman ◽  
G Goldberg ◽  
L H Bowman ◽  
D Steinmetz ◽  
D Schlessinger
Keyword(s):  
18S Rrna ◽  
23S Rrna ◽  
Homologous Sequence ◽  
28S Rrna ◽  
Evolutionary Analysis ◽  
Sequence Comparisons ◽  
Rdna Sequences ◽  
5.8S Rrna ◽  
Time Required ◽  
Ribosome Formation

Two regions of mouse rDNA were sequenced. One contained the last 323 nucleotides of the external transcribed spacer and the first 595 nucleotides of 18S rRNA; the other spanned the entire internal transcribed spacer and included the 3' end of 18S rRNA, 5.8S rRNA, and the 5' end of 28S rRNA. The mature rRNA sequences are very highly conserved from yeast to mouse (unit evolutionary period, the time required for a 1% divergence of sequence, was 30 X 10(6) to 100 X 10(6) years). In 18S rRNA, at least some of the evolutionary expansion and increase in G + C content is due to a progressive accretion of discrete G + C-rich insertions. Spacer sequence comparisons between mouse and rat rRNA reveal much more extensive and frequent insertions and substitutions of G + C-rich segments. As a result, spacers conserve overall G + C richness but not sequence (UEP, 0.3 X 10(6) years) or specific base-paired stems. Although no stems analogous to those bracketing 16S and 23S rRNA in Escherichia coli pre-rRNA are evident, certain features of the spacer regions flanking eucaryotic mature rRNAs are conserved and could be involved in rRNA processing or ribosome formation. These conserved regions include some short homologous sequence patterns and closely spaced direct repeats.

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