Cytokinin Activity of Ureidopurine Derivatives Related to a Modified Nucleoside Found in Transfer RNA

Dyson, William; Chen, C. M.; Alam, Syed N.; Hall, Ross H.; Hong, Chung Il; Chheda, Girish B.

doi:10.1126/science.170.3955.328

Cited by 32 publications

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References 13 publications

(14 reference statements)

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“…tRNA (900 A2omnm units) was isolated from the solids by a method previously described (9). This isolation was nonquantitative, and the product was contaminated with carbohydrate and various nucleic acid fragments.…”

Section: Methodsmentioning

confidence: 99%

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N⁶-(Δ²-Isopentenyl)adenosine: Its Occurrence as a Free Nucleoside in an Autonomous Strain of Tobacco Tissue

Dyson

Hall

1972

Plant Physiol.

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Cytokinins from both the free nucleoside pool and the transfer RNA have been isolated and identified in a habituated strain of tobacco pith callus (Nicotiana tabacum [L] var. Wisconsin 38). The transfer RNA of this strain contains both N0-(A2-isopentenyl) adenosine and N'-(4-hydroxy-3-methylbut-2-cis-enyl) adenosine. The trans-hydroxylated derivative is absent from the transfer RNA of this dark-grown tissue. N'-(A'-Isopentenyl)- Hall [14]). This hydroxylated derivative appears to be restricted to the tRNA of higher plants. In addition, the 2-methylthio derivatives of both the parent compound (z.2-iA) and the hydroxylated derivative have been isolated from the tRNA of wheat germ (6).The trans-isomer of ribosylzeatin (trans-RZ) and/or its free base and nucleotide have been found as free compounds in chicory roots (5) (8) showed that the A2-iA of the tRNA of this tissue is synthesized by attachment of a A2-isopentenyl side chain to the preformed tRNA. The requirement for the exogenous cytokinin does not seem to relate directly to this biosynthetic mechanism. In search, therefore, of leads that bear on the mechanism of action of cytokinins we decided to compare the A2-iA content of an autonomous line derived from the Wisconsin 38 strain of tobacco pith callus tissue (11) that grows well in the absence of exogenously added cytokinins. We have found that the tRNA of this strain also contains A2-iA and cis-RZ in its tRNA, but in contrast to the cytokinin-requiring strain the autonomous tissue contains a significant level of A2-iA in the free state. MATERIALS AND METHODSTissue Culture Strains. Normal tobacco pith tissue has an absolute requirement of added cytokinins for growth (11). Occasionally this normal tissue spontaneously loses its cytokinin requirement. Such autonomous strains of tissue presumably meet their cytokinin requirement through an alteration in some metabolic process, although the mechanism(s) of this transformation is not known.The normal cytokinin dependent tobacco pith tissue (Nicotiana tabacum [L] var. Wisconsin 38) and the derived autonomous strain used in this study were gifts from J. E. Fox of the University of Kansas. The normal pith tissue was grown on a previously described (11) basal medium containing naphthaleneacetic acid (1 mg per liter) and 6-furfurylaminopurine (kinetin) (1 mg per liter). The autonomous strain was grown on the same basal medium without the growth factors. Tissues were harvested after 4 to 5 weeks growth in the dark.Bioassay. Aliquots of column fractions to be bioassayed for cytokinin activity were added to 25-ml flasks and dried in vacuo over P20,. A basal medium (11), complete except for cytokinin, was added (10 ml per flask), and the flasks were autoclaved at 18 lb, 121 C for 5 min. A cytokinin requiring strain of soybean cotyledon tissue (Glycine max [L.] Merril, var. Acme) was planted (0.5 mg pieces, three per flask), and after 30 days incubation in the dark at room temperature, the increase in fresh weight was compared to controls grown in the presence (...

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Section: Methodsmentioning

confidence: 99%

“…tRNA was isolated from the autonomous tobacco tissue by a method previously described (9), except that the filtrate was used directly without cold storage. Cytokinin ribonucleotides were released from the tRNA by alkaline hydrolysis (0.3 N KOH for 24 hr at 37 C).…”

Section: Methodsmentioning

confidence: 99%

N⁶-(Δ²-Isopentenyl)adenosine: Its Occurrence as a Free Nucleoside in an Autonomous Strain of Tobacco Tissue

Dyson

Hall

1972

Plant Physiol.

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“…The reaction mixture was chromatographed on paper in solvents D and E. In both cases two discrete radioactive spots migrating coincidently with the two marker products were detected. 4. On treatment with KMnO4, i6Ado is oxidized to N6-(2,3-dihydroxy-3-methylbutyl)adenosine, adenosine, and a third unidentified product (27).…”

mentioning

confidence: 99%

“…Acme, were used to bioassay cytokinin activity (4,20). A strain of Zea inays L., NK 75, was grown in a greenhouse.…”

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trans-Ribosylzeatin

Miura¹,

Hall²

1973

Plant Physiol.

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When [8-14C]-N-(A'-isopentenyl) adenosine is incubated with the endosperm of corn (2 weeks after pollination), it is converted to ['4C]-N6-(4-hydroxy-3-methylbut-2-trans-enyl) adenosine, trans-ribosylzeatin. This biosynthetic step, N6-(A2-isopentenyl)adenosine to ribosylzeatin, also occurs in the mycorrhizal fungus, Rhizopogon roseolus.Cytokinin activity has been detected in extracts of various plants and plant organs. An active component in the extracts has been identified as trans-ribosylzeatin, trans-RZ2 (Fig. 1), in the case of immature fruit (16,17,20) and chicory root (2), and as its dihydro derivative in the case of Lupin (14) (see review by Kende (12) for a more detailed account). Recently Dyson and Hall (5) reported the presence of i6Ado in an extract of an autonomous strain of tobacco tissue. Of these naturally occurring cytokinins, trans-RZ exhibits the greatest activity in the tobacco callus bioassay system (9).As part of a study of the metabolism of cytokinins, we have investigated the biosynthesis of trans-RZ, and in this paper we describe its synthesis from the precursor, i6Ado. We chose systems known to contain free trans-RZ, a mycorrhizal fungus, Rhizopogon roseolus (22) and corn kernels (16,20

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Cyclische Aldehydderivate als Alkylierungsreagenzien, 2. Mitt. Aminoalkylderivate von 6‐Chlor‐ und 6‐Methylthiopurin und von Uracil

Griengl

Hayden

Kalchauer

et al. 1984

Archiv der Pharmazie

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Das aus 3-Methyl-l,3-oxazolidin (1) rnit Trimethyliodsilan in situ gebildete Iminiumsalz 2 gibt mit 6-Methylthiopurin das instabile Aminoalkylierungsprodukt 3a. Uracil geht mit 1 in die C-Munnich Base 5 uber, ein Azaacycloanaloges des Pseudouridins. Fur Stabilitatsvergleiche wurden die N-Mannich Basen 3b-3d und als Substrate fur biologische Studien die Ureidoderivate 4a-4e dargestellt . Cyclic Aldehyde Derivatives as Alkylating Reagents, 11: Aminoalkyl Derivatives of CChloroand Q(Methy1thio)purine and of Uracil"The iminium salt 2, formed in situ from 3-methyl-l,3-oxazolidine (1) with iodotrirnethylsilane, reacts with 6-(methylthio)purine to give the unstable aminoalkylation product 3a. From uracil and 1 the C-Mannich base 5 is obtained, an aza-acyclo analog of pseudouridine. For comparison of stabilities the N-Mannich bases 3b-3d and as substrates for biological studies the ureido derivatives 4 a 4 e have been sythesized.Ringoffnung von cyclischen Fiinfring-Acetalen, -Aminalen und -Mercaptalen fuhrt N mannigfaltig einsetzbaren Synthe~ebausteinen~". 3-Methyl-l,3-oxazolidine gehen dabei mit ProtonensBuren4) oder Trimethyli~dsilan~' in funktionalisierte Methyleniminiumsalze iiber. Als Munnich Reagenzien sollten diese bei Umsetzung mit Purinen und Pyrimidinen die entsprechenden (2-Hydroxyethy1)aminomethylverbindungen geben. Diese steilen einen neuen Strukturtyp von Azaacycloanalogen von Nucleosiden dar.

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Cytokinin Activity of Ureidopurine Derivatives Related to a Modified Nucleoside Found in Transfer RNA

Abstract: By use of a radioactive labeling technique N-(nebularin-6-ylcarbamoyl)threonine has been detected in plant transfer RNA. Derivatives of this nucleoside promote cell division of a cytokinin-requiring soya bean tissue.

Cited by 32 publications

References 13 publications

N⁶-(Δ²-Isopentenyl)adenosine: Its Occurrence as a Free Nucleoside in an Autonomous Strain of Tobacco Tissue

N⁶-(Δ²-Isopentenyl)adenosine: Its Occurrence as a Free Nucleoside in an Autonomous Strain of Tobacco Tissue

trans-Ribosylzeatin

Cyclische Aldehydderivate als Alkylierungsreagenzien, 2. Mitt. Aminoalkylderivate von 6‐Chlor‐ und 6‐Methylthiopurin und von Uracil

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Cytokinin Activity of Ureidopurine Derivatives Related to a Modified Nucleoside Found in Transfer RNA

Abstract: By use of a radioactive labeling technique N-(nebularin-6-ylcarbamoyl)threonine has been detected in plant transfer RNA. Derivatives of this nucleoside promote cell division of a cytokinin-requiring soya bean tissue.

Cited by 32 publications

References 13 publications

N6-(Δ2-Isopentenyl)adenosine: Its Occurrence as a Free Nucleoside in an Autonomous Strain of Tobacco Tissue

N6-(Δ2-Isopentenyl)adenosine: Its Occurrence as a Free Nucleoside in an Autonomous Strain of Tobacco Tissue

trans-Ribosylzeatin

Cyclische Aldehydderivate als Alkylierungsreagenzien, 2. Mitt. Aminoalkylderivate von 6‐Chlor‐ und 6‐Methylthiopurin und von Uracil

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N⁶-(Δ²-Isopentenyl)adenosine: Its Occurrence as a Free Nucleoside in an Autonomous Strain of Tobacco Tissue

N⁶-(Δ²-Isopentenyl)adenosine: Its Occurrence as a Free Nucleoside in an Autonomous Strain of Tobacco Tissue