Differential activation of free and template-engaged RNA polymerase I and II during the resumption of development of dormant Artemia gastrulae

Hentschel, Christopher C.; Tata, Jamshed R.

doi:10.1016/0012-1606(77)90216-0

Cited by 29 publications

(4 citation statements)

References 41 publications

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“…Heparin is known to have two effects: it inhibits binding of RNA polymerase to DNA, on the other hand it is also known to cause decondensation of chromatin and, therefore, to stimulate the rate of RNA synthesis, at least at low concentrations [2,6,7]. With the relatively high concentration used in our experiments (2 mg/ml) the decondensation effect presumably results in precocious termination, thereby strongly reducing the incorporation of the [32p] label in RNA during the 2 h incubation.…”

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confidence: 99%

Specific transcription and reinitiation of 2,4-D-induced genes in tobacco nuclei

et al. 1992

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In order to study the effects of trans-acting factors on cis-acting elements in plant genes an in vitro reinitiating nuclear transcription system is needed. Here we report that run-on experiments with nuclei isolated from 2,4-D-treated auxin-starved early-stationary-phase cells of tobacco clearly show reitintiation of transcription of specific 2,4-D-induced genes. Using gamma-thio nucleotides and [alpha-32P]-UTP we were able to demonstrate the presence of reinitiated labelled specific RNAs after isolation on a mercury-agarose affinity column. Addition of heparin as an inhibitor blocked this reinitiation. In a primer extension assay we found that the new transcripts initiate at approximately the same site as used in vivo.

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confidence: 99%

Specific transcription and reinitiation of 2,4-D-induced genes in tobacco nuclei

et al. 1992

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“…(a) In agreement with earlier reports (Yu, 1974(Yu, , 1975a), the total nuclear free RNA polymerase is a significant fraction (40-50%) of the total nuclear RNA polymerase population. The importance of this fraction of RNA polymerase in the elucidation of the mechanism of hormone action, chemical carcinogenesis, cell growth and differentiation is well illustrated in several reports from our (Yu & Feigelson, 1971;Yu, 1975b;Yu & Grunberger, 1976;Yu, 1977) and other laboratories (Adams & Goodman, 1976;Fuhrman & Gill, 1976;Hentschel & Tata, 1977: Anderson et al, 1977Zonchedder et al, 1977;Kellas et al, 1977). (b) The total activity (free plus engaged) of RNA polymerases I, II and III each accounts for about one-third of the total nuclear RNA polymerase activity.…”

Section: Resultsmentioning

confidence: 87%

High concentration of RNA polymerase I is responsible for the high rate of nucleolar transcription

Yu¹

1980

Biochemical Journal

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When isolated rat liver nuclei and nucleoli are compared for RNA synthesis in vitro, the rate of nucleolar RNA synthesis is found to be more than 10 times higher. In order to understand this high rate of nucleolar transcription, DNA from both nuclear and nucleolar fractions was isolated and compared for the ability to direct RNA synthesis with homologous RNA polymerases. No difference between these two templates is evident. On the other hand, when the total nuclear and nucleolar RNA polymerases are isolated and compared on a per-unit-weight-of-DNA basis, it becomes clear that the nucleolus has a 10-fold higher RNA polymerase concentration than the nucleus. This result suggests that RNA polymerase I concentration rather than the nucleolar DNA template efficiency is responsible for the observed high rate of nucleolar transcription under the normal steady-state condition.

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“…A second fraction, 'free' enzyme, is not associated with chromatin and is therefore thought to be functionally inactive (Matsui et al, 1976). The two populations of RNA polymerase I have been shown to exhibit independent responses to carcinogen administration (Leonard & Jacob, 1977) as well as to physiological stimuli (Yu, 1975b;Hentschel & Tata, 1977;Tillyer & Butterworth, 1978;Biining, 1978). Therefore it was decided to determine whether the increases in polymerase enzymes observed in Morris hepatomas relative to liver reflected changes in the functionally active population.…”

Section: Resultsmentioning

confidence: 99%

Transcriptionally active RNA polymerases from Morris hepatomas and rat liver. Elucidation of the mechanism for the preferential increase in the tumour RNA polymerase I

Duceman¹,

Jacob²

1980

Biochemical Journal

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The amount and/or activity of DNA-dependent RNA polymerase I, Ii and III from resting liver, regenerating liver and a series of Morris hepatomas (5123D, 7800, 7777, 3924A) were determined after extraction of the enzymes from whole tissue homogenates and subsequent fractionation by DEAE-Sephadex column chromatography. When compared with resting liver, the tumours exhibited a characteristic enzyme pattern in which polymerase I, but not II, was increased. The increase in RNA polymerase I was proportional to the tumour growth rates. Alterations in polymerase III were confined to the most rapidly proliferating hepatomas. By contrast, all classes of RNA polymerase were found to be increased during liver regeneration. Relative to resting liver, the fastest growing tumour, 3924A, exhibited the highest activities and/or amounts of RNA polymerase I (8-fold) and III (5-fold) per g of tissue. These alterations in the tumour RNA polymerases were reflected in corresponding increases in the transcriptionally active (bound or chromatin-associated) enzyme population. The mechanisms underlying the augmented synthesis of RNA in vitro by bound polymerase I from hepatoma 3924A were elucidated by product analysis. The results indicated that, relative to liver RNA polymerase I, the tumour enzyme produced more nascent RNA chains and elongated these chains at a faster rate. The number of 3'-termini, as measured by incorporation into uridine, was higher in the hepatoma even under conditions which prevented re-initiation. suggesting increased amount of transcriptionally active RNA polymerase I in the tumour.

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Differential activation of free and template-engaged RNA polymerase I and II during the resumption of development of dormant Artemia gastrulae

Cited by 29 publications

References 41 publications

Specific transcription and reinitiation of 2,4-D-induced genes in tobacco nuclei

Specific transcription and reinitiation of 2,4-D-induced genes in tobacco nuclei

High concentration of RNA polymerase I is responsible for the high rate of nucleolar transcription

Transcriptionally active RNA polymerases from Morris hepatomas and rat liver. Elucidation of the mechanism for the preferential increase in the tumour RNA polymerase I

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