Increased Activity of Chromatin-bound Ribonucleic Acid Polymerase from Soybean Hypocotyl with Spermidine and High Ionic Strength

Guilfoyle, Tom J.; Hanson, James A.

doi:10.1104/pp.51.6.1022

Cited by 25 publications

(12 citation statements)

References 33 publications

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“…By contrast the effect of polyamines on nucleic acid metabolism in tissues of higher plants has been studied little, but in these few cases, positive results were obtained. RNA synthesis in Helianthus tuberosus was stimulated by polyamines (1) and spermidine interacted with chromatin-bound RNA polymerase of soybean hypocotyl to increase its activity (8).…”

Section: Discussionmentioning

confidence: 99%

“…Subsequently, the basic amino acids L-arginine and L-lysine were found to have similar effects, some of which are described here. In view of the rapid metabolism of these two amino acids to diamines occurring naturally in plant tissues (16), the ability of diamines to stabilize bacterial protoplasts against Iysis (19), and their involvement in nucleic acid synthesis in many procaryotic and eucaryotic organisms (18) including some plants (1,8,16), we studied the effects of various amines and related substances on macromolecular synthesis and morphological stability of oat leaf protoplasts.…”

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confidence: 99%

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Stabilization of Oat Leaf Protoplasts through Polyamine-mediated Inhibition of Senescence

Altman¹,

Kaur‐Sawhney²,

Galston³

1977

Plant Physiol.

168

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Protoplasts isolated from Avena sativa L. leaves undergo progressive senescence when incubated aseptically in 0.6 M mannitol with or without added nutrients. This senescence is manifested by morphological deterioration and ultimate iysis of protoplasts, by a decrease in incorporation of [3HJuridine and I3Hlleucine into macromolecules, and by a sharp increase in ribonuclease activity.The presence in the incubation medium of L-arginine, L-lysine, certain polyamines related to these amino acids (cadaverine, putrescine, spermidine), Ca2+, or streptomycin stabilizes the protoplasts. Protoplasts incubated with 10 mM L-arginine or L-lysine show an initial inhibition of [3Hluridine incorporation, but with time, incorporation is restored to levels greater than in control protoplasts. The rise in ribonudease activity of protoplasts is completely inhibited if the protoplasts are incubated with 10 mM L-arginine. Greater incorporation of I3Hluridine into RNA of aging protoplasts is also maintained by appropriate concentration of cadaverine, putrescine, spermidine, Ca2+, or streptomycin in the incubation medium; the same concentrations of these substances stabilize the protoplasts against additional lysis.Isolated plant cells and protoplasts in culture usually have a shorter life span than similar cells in the intact plant, and tend to undergo senescence rapidly. In a few plant species, including asparagus, rape, carrot, petunia, and tobacco (2, 3), protoplasts are capable of cell wall formation, cell division, and even regeneration of entire plants. By contrast, protoplasts of cereals, legumes, and other economically important plants do not readily divide. With regard to oat leaf protoplasts, it has been suggested that morphological instability and deterioration are related to a complex of senescence-induced changes following leaf excision and isolation of protoplasts from mesophyll cells (6, 9; Galston et al., unpublished). Apart from their morphological instability, nondividing protoplasts also show a time-dependent decline in incorporation of precursors into protein and RNA (4,6,20), and an increase in ribonuclease activity and consequent breakdown of endogenous RNA (9,20; Galston et al., unpublished).Previous experiments have established that pretreatment of excised oat leaves with cycloheximide and kinetin can retard postexcision senescent changes in the leaf, yielding protoplasts which are more resistant to spontaneous lysis and more active in protein and nucleic acid synthesis (9). Subsequently, the basic amino acids L-arginine and L-lysine were found to have similar effects, some of which are described here. rapid metabolism of these two amino acids to diamines occurring naturally in plant tissues (16), the ability of diamines to stabilize bacterial protoplasts against Iysis (19), and their involvement in nucleic acid synthesis in many procaryotic and eucaryotic organisms (18) including some plants (1, 8, 16), we studied the effects of various amines and related substances on macromolecular synthesis and morp...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Stabilization of Oat Leaf Protoplasts through Polyamine-mediated Inhibition of Senescence

Altman¹,

Kaur‐Sawhney²,

Galston³

1977

Plant Physiol.

168

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“…This large accumulation of RNA in the mature tissue is associated with an enhanced chromatin-directed RNA synthetic activity (3). The auxin-enhanced chromatin activity is insensitive to a-amanitin (4), indicating that the increased RNA synthetic activity relates to a nucleolar type RNA polymerase as described in animals (e.g., ref. 5).…”

mentioning

confidence: 95%

Enhancement of soybean RNA polymerase I by auxin.

Guilfoyle¹,

Lin²,

Chen³

et al. 1975

Proc. Natl. Acad. Sci. U.S.A.

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When etiolated soybean seedlings are treated with the synthetic auxin, 2,4-dichlorophenoxyacetic acid, cells of the mature hypocotyl become swollen and proliferate abnormally. This abnormal growth induced by auxin coincides with a 5-to 8-fold increase in the a-amanitin-insensitive RNA polymerase associated with isolated chromatin or nuclei. The a-amanitin-sensitive RNA polymerase activity of the auxin-treated hypocotyl was similar to that of control tissue. The increase in RNA polymerase I activity of chromatin and nuclei was maintained after solubilization and fractionation on DEAEcellulose. Auxin thus appears to enhance RNA synthetic activity (i.e., ribosomal RNA) in mature soybean tissue by altering RNA polymerase I directly rather than by altering the chromatin template.When the synthetic auxin, 2,4-dichlorophenoxyacetic acid (2,-4-D), is applied to young etiolated soybeans, cells of the mature hypocotyl enlarge radially and proliferate, while the normal growing point or apical meristem becomes quiescent. The abnormal proliferation of the mature hypocotyl is preceded by a large increase in RNA, especially ribosomal RNA (1, 2). This large accumulation of RNA in the mature tissue is associated with an enhanced chromatin-directed RNA synthetic activity (3). The auxin-enhanced chromatin activity is insensitive to a-amanitin (4), indicating that the increased RNA synthetic activity relates to a nucleolar type RNA polymerase as described in animals (e.g., ref. 5). Hybridization studies also indicate that the chromatin-bound RNA polymerase is transcribing primarily ribosomal RNA (6). Recent studies indicate that soybean chromatin isolated by conventional methodology (7) in fact possesses only RNA polymerase I activity, while nearly all RNA polymerase II is found in high-speed supernatant fractions (8).In the present work the effects of the synthetic auxin, 2,4-D, on RNA polymerase I and II activities from both chromatin and nuclei were studied. The enzymes were solubilized and fractionated on DEAE-cellulose. RNA polymerase I activity increased several-fold after auxin treatment, while RNA polymerase II activity was at most only slightly affected. MATERIALS AND METHODSPlant Material. Soybean seeds (Glycine max, var, Wayne) that had been pretreated with 10% Chlorox were planted in Abbreviations: 2,4-D, 2,4-dichlorophenoxyacetic acid; buffer A, 50 mM Tris-HCl (pH 8.0), 10 mM 2-mercaptoethanol, 1 mM MgCl2, 250 mM sucrose, 0.1 mM EDTA, and 0.5 mM phenylmethylsulfonylfluoride; buffer B, 50 mM Tris -HCl (pH 8.0), 10 mM dithiothreitol, 5 mM MgC12, 25% glycerol, 0.1 mM EDTA, and 0.5 mM phenylmethylsulfonyliluoride. (8).Preparation of Soybean Nuclei. Nuclei were isolated and purified by a modification of the procedure described by Stern (9). The details of this procedure will be described in a forthcoming publication.Preparation of Soybean RNA Polymerases. RNA polymerase I was solubilized by stirring chromatin suspensions for 5 hr at 00 in the presence of buffer B containing 500 mM ammonium sulfate. The solubiliz...

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“…Many roles have been suggested for polyamines including enhancement of RNA synthesis (2,8), activation of RNA polymerase (10), and stabilization of DNA and RNA during replication (17,24,25), but their precise function is still not fully understood.…”

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confidence: 99%

Polyamine Biosynthetic Enzymes in the Cell Cycle of Chlorella

Cohen¹,

Arad²,

Heimer³

et al. 1984

Plant Physiol.

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During the life cycle of Chlorella vulgaris Beijerinck var vulgaris fa. vulgaris growing synchronously, the specific activity of ornithine decarboxylase peaked at the 2nd hour of the cycle, whereas that of arginine decarboxylase changed only slightly, increasing towards the end of the cycle. The endogenous level of putrescine and spermidine on a per cell basis increased gradually up to the 8th hour of the cycle, and declined thereafter. Thus, the peak of ornithine decarboxylase activity and the polyamine increase preceded both DNA replication (which took place between the 6th and 8th hours of the cycle) and autospore release (which started at the 8th hour). A 2-fold increase in the light intensity caused doubling of the DNA content, resulting in doubling of the number of autospores per mother cell. It also brought about a 2-fold increase in the specific activity of ornithine decarboxylase and polyamine content, the peaks being at the same hour of the cycle under high and low light intensities. The increase in cell number and polyamine content in a Chlorella culture grown under high light intensity was inhibited by adifluoromethyl ornithine, a specific inhibitor of ornithine decarboxylase, this inhibition being partially reversed by putrescine.It is suggested that in C. vulgaris the sequence of events which relates polyamine biosynthesis to cell division is as follows: increased ornithine decarboxylase activity, accumulation of polyamines, DNA replication, and autospore release.

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Increased Activity of Chromatin-bound Ribonucleic Acid Polymerase from Soybean Hypocotyl with Spermidine and High Ionic Strength

Cited by 25 publications

References 33 publications

Stabilization of Oat Leaf Protoplasts through Polyamine-mediated Inhibition of Senescence

Stabilization of Oat Leaf Protoplasts through Polyamine-mediated Inhibition of Senescence

Enhancement of soybean RNA polymerase I by auxin.

Polyamine Biosynthetic Enzymes in the Cell Cycle of Chlorella

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