Halogenated Ribofuranosylbenzimidazoles

Tamm, Igor; Sehgal, Pravinkumar B.; Lamb, Robert A.; Goldberg, Andrew V.

doi:10.1007/978-1-4613-3804-8_14

Cited by 6 publications

(3 citation statements)

References 88 publications

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“…Synthesis of these RNAs persists in the presence of 5,6-dichloro-1-,B3D-ribofuranosylbenzimidazole (DRB), which apparently reduces the synthesis of productive transcripts (5). These results were interpreted to imply premature termination of transcription in adenovirus.…”

mentioning

confidence: 99%

Pausing and premature termination of human RNA polymerase II during transcription of adenovirus in vivo and in vitro.

Maderious¹,

Chen‐Kiang²

1984

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

106

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The major late transcriptional unit of adenovirus type 2 has served as a model for studying transcription in eukaryotes. We report that pausing and premature termination are intrinsic to the transcription of this transcriptional unit by RNA polymerase II. In vivo and in isolated nuclei, transcription pauses at discrete sites proximal to the initiation site and can prematurely terminate at nucleotide 175 and possibly also at nucleotide 120. The prematurely terminated RNAs are not associated with the transcription complexes and accumulate in the cell nucleus in vivo, whereas paused RNAs remain associated with the transcription complexes and elongate into full-length transcripts. Pausing is also reproduced in the transcription complexes in a soluble system. 5,6-Dichloro-1-1&D-ribofuranosylbenzimidazole enhances pausing but not premature termination, and its action is reversible. The proposed premature termination site at nucleotide 175 in adenovirus type 2 bears sequence homology to the tRI site in coliphage A.In eukaryotes, the expression of both cellular and viral genes appears to be regulated primarily at the transcriptional level (1). In prokaryotes, transcription is regulated not only at the level of initiation but also by attenuation-the termination of transcription shortly following initiation (2). Little is known about the mechanism and regulation of transcription initiation in eukaryotes, and virtually nothing is understood about the events associated with elongation and termination. Adenovirus type 2 (Ad-2)-infected HeLa cells contain small RNA species complementary to the promoter-proximal region of the major late transcription unit; these are represented in extramolarity compared to other regions of the unit at steady state in vivo (3) and in isolated nuclei (4). Synthesis of these RNAs persists in the presence of 5,6-dichloro-1-,B3D-ribofuranosylbenzimidazole (DRB), which apparently reduces the synthesis of productive transcripts (5). These results were interpreted to imply premature termination of transcription in adenovirus. Premature termination was also suggested to occur in Chinese hamster cells (6) and in globinproducing cells (7), where DRB had a similar effect. However, the critical experiments to ascertain the fate of these small transcripts have not been performed. Although promoter-proximal "attenuation" has been suggested to occur in simian virus 40 due to the appearance of a small RNA during transcription in vitro (8), the existence of this small RNA in simian virus 40-infected cells has not been demonstrated.Although pausing during transcription has not been observed in the transcription of eukaryotic genes in vivo, it is a common occurrence in the transcription of bacterial and phage genes (9). Kadesch and Chamberlain (10) reported that polymerase II from calf thymus pauses during transcription of a T7 bacteriophage template in vitro. Coppola et al.(11) found that in a soluble system under limited substrate concentration, the human polymerase II pauses within 30 nucleotides (nt)...

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confidence: 99%

Pausing and premature termination of human RNA polymerase II during transcription of adenovirus in vivo and in vitro.

Maderious¹,

Chen‐Kiang²

1984

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

106

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“…Because the nucleolus is transcriptionally highly active, attempts were made to determine if the antigen bound by W8 was involved in ribosomal RNA synthesis and possibly associated with the transcriptional units of the ribosome. This was evaluated by using the two antimetabolites, DRB and actinomycin D. DRB has been shown to cause nucleolar dispersal or fragmentation while inhibiting messenger but not ribosomal RNA transcription (31,32). Appropriate doses of actinomycin D suppress ribosomal RNA synthesis without causing nucleolar dispersal (33).…”

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confidence: 99%

Description and partial characterization of a nucleolar RNA-associated autoantigen defined by a human monoclonal antibody.

Chiorazzi¹,

Reeves²

1987

The Journal of Experimental Medicine

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B lymphocytes from a patient with systemic lupus erythematosus (SLE) and several circulating autoantibodies (including antinucleolar antibodies) were immortalized by fusion with a hypoxanthine/guanine phosphoribosyl transferase (HGPRT)-deficient human B cell line. Multiple human monoclonal antibodies (mAb) were obtained which, in solid-phase enzyme immunoassay, were reactive with DNA. One mAb was of special interest because it reacted strongly with both single-stranded DNA and an extractable nuclear antigen found in rabbit thymus extract (RTE). In an immunofluorescent assay using fixed human cells, the latter mAb also bound predominantly to cell nucleoli. A combination of enzyme digestion and metabolic inhibitor studies of the target cells in this immunofluorescent assay suggested that the antigen(s) bound by the mAb was an RNA-associated protein or a ribonucleoprotein that is distinct from intact RNA polymerase I and not associated with the transcriptional units of the nucleolus. In other experiments, using fractions of RTE isolated by ion-exchange chromatography, the antigens bound by the mAb were shown to be highly negatively charged molecules. Immunoprecipitation and SDS-PAGE analyses of labeled cell extracts bound by the mAb revealed a doublet of 17 and 18 kD. Since the original patient's serum autoantibodies also bound to both an RNase-sensitive, acidic, extractable nuclear antigen and to nucleoli, and immunoprecipitated proteins of similar molecular masses in SDS-PAGE, it appears that the described mAb is a product of an immortalized autoantibody-producing B cell clone from the SLE patient's peripheral blood. This mAb probably defines a novel RNA-associated autoantigen residing predominantly in the nucleolus or, less likely, a variant of either RNA polymerase I or the ribosomal autoantigens (P proteins).

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“…In the present study we used the isolation technique described by Sass (35) to collect unfixed individual polytene chromosomes, in particular chromosome IV, which harbors the giant tissue specific Balbiani rings (BRs) (2,6,34). Transcriptional modulation by selective inactivation of heterogeneous nuclear RNA (hnRNA) genes was induced by the nucleoside analogue 5,6dichloro-l-ß-D-ribofuranosylbenzimidazole (DRB) (for review, see reference 44). The inhibitory effect of DRB is noticeable within minutes (12) and it leads tó a reformation of thick chromosome fiber in parallel with the repression of hnRNA genes (1).…”

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confidence: 99%

Phosphorylation of some chromosomal nonhistone proteins in active genes is blocked by the transcription inhibitor 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB).

Egyházi¹,

Pigon²,

Ossoinak³

et al. 1984

The Journal of Cell Biology

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The distribution of rapidly phosphorylated chromosomal proteins between chromosome I, chromosome II + III, chromosome IV, and nuclear sap including the matrix was investigated in salivary gland cells of Chironomus tentans . Chromosome IV, which carries most active nonribosomal genes in the cell, was found to be enriched in four rapidly phosphorylated nonhistone polypeptides (Mr = 25,000,30,000,33,000,and 42,000) in parallel with the transcriptional activity rather than with the DNA content of the chromosome. Also the histones H2A and H4 are rapidly phosphorylated but the phosphorylation is proportional to the DNA content of each chromosome sample . The 32 P-labeled Mr = 42,000 polypeptide immunologically cross-reacted with an antibody elicited against the transcription stimulatory factor S-II isolated from Ehrlich ascites tumor cells (Sekimizu, K ., D . Mizuno, and S. Natori, 1979, Exp. Cell Res ., 124 :63-72) . In addition, indirect immunofluorescence studies on chromosome IV with antisera against the stimulatory factor II revealed a selective staining of the active gene loci. The incorporation of 32 P into three chromosome IV nonhistone polypeptides, especially into the Mr = 42,000 polypeptide, was lowered by 70-85% shortly after administration of 5,6-dichloro-1-ß-D-ribofuranosylbenzimidazole (DRB), a likely inhibitor of heterogeneous nuclear RNA transcription at initiation level. The possibility of a causal relationship between inhibited phosphorylation of chromosomal proteins and blocked transcription of heterogeneous nuclear RNA genes by DRB is discussed .The nature ofevents involved in regulation ofeukaryotic gene expression at the transcriptional level is still to a large extent unknown . The recognition ofinitiation sites and the sequence ofevents involved in the step of transcription initiation play, in all likelihood, a crucial role in the exertion of gene control (for review, see reference 8). An important regulatory potential lies in the structure of chromatin . Unfolding of tightly packed chromatin fibers at selected gene loci may facilitate the finding of initiation sites by RNA polymerase molecules and transcription factors, and may guide the initiation reaction itself. Transcriptional regulatory potential may also lie in the concentration and chemical modification ofRNA polymerase and in specific transcription factors that may act independently on, or in cooperation with, RNA polymerase . Thus the identification ofmolecules and molecular assemblies with regulatory function and the elucidation of the significance of postsynthetic protein modifications as phosphorylation, acetylation, methylation, etc . in gene control require analysis of structural as well as catalytic constituents of the chromatin (for reviews, see references 42 and 46). On the basis of the involvement of posttranslational protein phosphorylation in many cellular regulatory mechanisms (for reviews, see references 20 and 37) and because of the observed modulation of specific chromosomal phosphoproteins in transcription...

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Halogenated Ribofuranosylbenzimidazoles

Cited by 6 publications

References 88 publications

Pausing and premature termination of human RNA polymerase II during transcription of adenovirus in vivo and in vitro.

Pausing and premature termination of human RNA polymerase II during transcription of adenovirus in vivo and in vitro.

Description and partial characterization of a nucleolar RNA-associated autoantigen defined by a human monoclonal antibody.

Phosphorylation of some chromosomal nonhistone proteins in active genes is blocked by the transcription inhibitor 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB).

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