Wheat embryo ribonucleates. X. Metabolism of 3′-hydroxyl termini in the conserved mRNA and tRNA of imbibing wheat embryos

1978 ◽  
Vol 56 (3) ◽  
pp. 197-202 ◽  
Author(s):  
T. D. Kennedy ◽  
B. G. Lane
Keyword(s):  
Ribosomal Rna ◽  
Messenger Rna ◽  
Insoluble Fraction ◽  
Wheat Embryo ◽  
Selective Labelling ◽  
Wheat Embryos ◽  
Chain Lengths ◽  
Hydroxyl Termini ◽  
Terminal Poly ◽  
Mass Component

There are conserved complements of ribosomal RNA (rRNA), transfer RNA (tRNA), and messenger RNA (mRNA) in dry wheat embryos. Although early labelling of RNA is largely directed toward the synthesis of complete molecules of nascent rRNA and mRNA, there is also selective labelling at 3′-hydroxyl termini in conserved polynucleotides when dry wheat embryos are subjected to short-term (0.5 h) imbibition in a medium that contains tritium-labelled adenosine, guanosine, cytidine, and uridine. Conserved tRNA is the principal mass component in NaCl-soluble RNA (sRNA) and most of the 'rapid labelling' of sRNA (rl-sRNA) is a result of labelling at 3′-hydroxyl termini in conserved tRNA. By contrast, although conserved rRNA is the principal mass component in NaCl-insoluble RNA (iRNA), most of the labelled 3′-hydroxyl termini in 'rapidly labelled' iRNA (rl-iRNA) do not appear to derive from rRNA. Although about 10% of the labelled 3′-hydroxyl termini in rl-iRNA originates in conserved poly(A)-rich mRNA, the available evidence leads to the conclusion that most of the labelled 3′-hydroxyl termini in rl-iRNA originates in an unusual NaCl-insoluble fraction of conserved tRNA. During the course of extended imbibition, between 0.5 and 5 h, there are characteristic changes in the chain lengths and labelling patterns for 3′-hydroxyl terminal poly(A) sequences in mRNA. Analytical and physiological implications of these data are subjects of 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.

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. II. 3′-Hydroxyl Termini of the Satellite, 18 S, and 26 S Ribosomal Ribonucleates

1973 ◽  
Vol 51 (8) ◽  
pp. 1195-1202 ◽  
Author(s):  
A. A. Azad ◽  
B. G. Lane
Keyword(s):  
Ribosomal Rna ◽  
Source Material ◽  
Satellite Rna ◽  
Wheat Embryo ◽  
Hydroxyl Termini

(1) Terminal labelling with (3H)-borohydride has been used as a means of examining the 3′-hydroxyl termini in wheat embryo RNA.(2) The principal 3′-hydroxyl termini in the "satellite," 18 S, and 26 S components of wheat-embryo ribosomal RNA have been found to be cytidine, guanosine, and uridine, respectively.(3) The occurrence of 3′-hydroxyl terminal cytidine, in satellite RNA, and 3′-hydroxyl terminal guanosine, in 18 S RNA, has never been observed for the corresponding ribosomal ribonucleates from any other source material. The possible significance of this "irregularity" is a subject of 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.

Synthesis and turnover of proteins and mRNA in germinating wheat embryos

1982 ◽  
Vol 60 (3) ◽  
pp. 389-397 ◽  
Author(s):  
Zbyszko F. Grzelczak ◽  
Mark H. Sattolo ◽  
Linda K. Hanley-Bowdoin ◽  
Theresa D. Kennedy ◽  
Byron G. Lane
Keyword(s):  
Growth Phase ◽  
Time Course ◽  
Phase 1 ◽  
Major Product ◽  
Lag Phase ◽  
Wheat Embryo ◽  
Phase Development ◽  
Wheat Embryos

The most prominent methionine-labeled protein made when cell-free systems are programmed with bulk mRNA from dry wheat embryos has been identified with what may be the most abundant protein in dry wheat embryos. The protein has been brought to purity and has a distinctive amino acid composition, Gly and Glx accounting for almost 40% of the total amino acids. Designated E because of its conspicuous association with early imbibition of dry wheat embryos, the protein and its mRNA are abundant during the "early" phase (0–1 h) of postimbibition development, and easily detected during "lag" phase (1–5 h), but they are almost totally degraded soon after entry into the "growth" phase of development, by about 10 h postimbibition.The most prominent methionine-labeled protein peculiar to the cell-free translational capacity of bulk mRNA from "growth" phase embryos is not detected as a product of in vivo synthesis. Its electrophoretic properties and its time course of emergence, after 5 h postimbibition development, suggest that this major product of cell-free synthesis may be an in vitro counterpart to a prominent methionine-labeled protein made only in vivo, by "growth" phase embryos. Designated G because of its conspicuous association with "growth" phase development, the cell-free product does not comigrate with any prominent dye-stained band in electrophoretic distributions of wheat proteins. The suspected cellular counterpart to G, also, does not comigrate with a prominent dye-stained wheat protein during electrophoresis, and although found in particulate as well as soluble fractions of wheat embryo homogenates it is not concentrated in either nuclei or mitochondria, as isolated.

scholarly journals Genetics of in vitro organogenesis and precocious germination of wheat embryos

1998 ◽  
Vol 21 (1) ◽  
pp. 87-92 ◽  
Author(s):  
Claudia E. Lange ◽  
Luiz C. Federizzi ◽  
Fernando I.F. Carvalho ◽  
Ana L.C. Dornelles ◽  
Cristine L. Handel
Keyword(s):  
Gene Action ◽  
Precocious Germination ◽  
Genetic Determination ◽  
Wheat Embryo ◽  
In Vitro Organogenesis ◽  
Generation Means ◽  
Generation Means Analysis ◽  
Wheat Embryos ◽  
Segregating Population

The genetic bases of in vitro organogenesis and precocious germination of embryos in immature wheat embryo culture were investigated using six Brazilian genotypes and their F1, F2, BC1F1 and BC2F1 generations in a generation means analysis. Four parents and one set of F1’s were also analyzed in a diallel experiment. The results indicated a complex gene action controlling both traits, with additive, dominant and epistatic effects. High broad sense heritability values were found, indicating genetic determination. Considering the complexity of gene control, genetic gain could be achieved by selecting for the traits in advanced generations of the segregating population. Low correlation values between organogenesis, precocious germination, regeneration and somatic embryogenesis (data shown in a previous report) indicated the possibility of obtaining recombinant genotypes.

"Cap" sequences is poly(A)-rich RNA from dry wheat embryos

1981 ◽  
Vol 59 (10) ◽  
pp. 868-870 ◽  
Author(s):  
Byron G. Lane
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Messenger Rna ◽  
High Performance ◽  
Higher Plants ◽  
Rna Molecules ◽  
Wheat Embryos ◽  
The Subject ◽  
Widespread Interest

Although template-active RNA in dry seeds and embryos has attracted widespread interest, there have been no published reports about 5′-terminai "capping" sequences in such RNA. Boro[3H]hydride labeling of periodate-oxidized termini and high performance liquid chromatography of cap oligonucleotides have been used to compare terminal sequences in poly(A)-rich RNA from dry and germinating embryos. As is the case in germinating embryos, poly(A)-rich RNA from dry embryos contains only "type 0" cap sequences, i.e., m7G(5′)ppp(5′)N, in which m7G is the 7-methylguanosine cap and N is any of the classical ribonucleosides: adenosine (A), guanosine (G), cytidine (C), and uridine (U). Striking differences between the cell-free translational capacities of bulk messenger RNA (mRNA) populations from dry and germinating embryos are not reflected in signal differences in their proportions of "type 0" cap structures: in general, there is approximately 40% m7G(5′)ppp(5′)A, with roughly equivalent amounts of m7G(5′)ppp(5′)G and m7G(5′)ppp(5′)C accounting for most of the remaining sequences. The findings with mRNA from dry plant embryos serve to emphasize interesting differences between patterns of methylation in the capped and uncapped RNA molecules in higher plants and animals; these differences have not been previously noted in the literature and are the subject of brief comment in this paper.

scholarly journals Unusual pattern of ribonucleic acid components in the ribosome of Crithidia fasciculata, a trypanosomatid protozoan.

1981 ◽  
Vol 1 (4) ◽  
pp. 347-357 ◽  
Author(s):  
M W Gray
Keyword(s):  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
Large Subunit ◽  
Ribosomal Subunit ◽  
Ribosomal Rnas ◽  
High Potassium ◽  
Intact Cells ◽  
Crithidia Fasciculata ◽  
Low Magnesium ◽  
Chain Lengths

In a previous study from this laboratory, presumptive ribosomal ribonucleic acid (RNA) species were identified in the total cellular RNA directly extracted from intact cells of the trypanosomatid protozoan Crithidia fasciculata (M. W. Gray, Can. J. Biochem. 57:914-926, 1979). The results suggested that the C. fasciculata ribosome might be unusual in containing three novel, low-molecular-weight ribosomal RNA components, designated e, f, and g (apparent chain lengths 240, 195, and 135 nucleotides, respectively), in addition to analogs of eucaryotic 5S (species h) and 5.8S (species i) ribosomal RNAs. In the present study, all of the presumptive ribosomal RNAs were indeed found to be associated with purified C. fasciculata ribosomes, and their localization was investigated in subunits produced under different conditions of ribosome dissociation. When ribosomes were dissociated in a high-potassium (880 mM K+, 12.5 mM Mg2+) medium, species e to i were all found in the large ribosomal subunit, which also contained an additional, transfer RNA-sized component (species j). However, when subunits were prepared in a low-magnesium (60 mM K+, 0.1 mM Mg2+) medium, two of the novel species (e and g) did not remain with the large subunit, but were released, apparently as free RNAs. Control experiments have eliminated the possibility that the small RNAs are generated by quantitative and highly specific (albeit artifactual) ribonuclease cleavage of large ribosomal RNAs during isolation. In terms of RNA composition and dissociation properties, therefore, the ribosome of C. fasciculata is the most "atypical" eucaryotic ribosome yet described. These observations raise interesting questions about the function and evolutionary origin of C. fasciculata ribosomes and about the organization and expression of ribosomal RNA genes in this organism.

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