Balbiani ring nucleotide sequences in cytoplasmic 75 S RNA of Chironomus tentans salivary gland cells

1974 ◽  
Vol 1 (8) ◽  
pp. 457-464 ◽  
Author(s):  
B. Lambert ◽  
J. -E. Edstr�m
1987 ◽  
Vol 7 (12) ◽  
pp. 4308-4316
Author(s):  
E Egyházi ◽  
E Durban

Purified anti-topoisomerase I immunoglobulin G (IgG) was microinjected into nuclei of Chironomus tentans salivary gland cells, and the effect on DNA transcription was investigated. Synthesis of nucleolar preribosomal 38S RNA by RNA polymerase I and of chromosomal Balbiani ring RNA by RNA polymerase II was inhibited by about 80%. The inhibitory action of anti-topoisomerase I IgG could be reversed by the addition of exogenous topoisomerase I. Anti-topoisomerase I IgG had less effect on RNA polymerase II-promoted activity of other less efficiently transcribing heterogeneous nuclear RNA genes. The pattern of inhibition of growing nascent Balbiani ring chains indicated that the transcriptional process was interrupted at the level of chain elongation. The highly decondensed state of active Balbiani ring chromatin, however, remained unaffected after injection of topoisomerase I antibodies. These data are consistent with the interpretation that topoisomerase I is an essential component in the transcriptional process but not in the maintenance of the decondensed state of active chromatin.


1987 ◽  
Vol 7 (12) ◽  
pp. 4308-4316 ◽  
Author(s):  
E Egyházi ◽  
E Durban

Purified anti-topoisomerase I immunoglobulin G (IgG) was microinjected into nuclei of Chironomus tentans salivary gland cells, and the effect on DNA transcription was investigated. Synthesis of nucleolar preribosomal 38S RNA by RNA polymerase I and of chromosomal Balbiani ring RNA by RNA polymerase II was inhibited by about 80%. The inhibitory action of anti-topoisomerase I IgG could be reversed by the addition of exogenous topoisomerase I. Anti-topoisomerase I IgG had less effect on RNA polymerase II-promoted activity of other less efficiently transcribing heterogeneous nuclear RNA genes. The pattern of inhibition of growing nascent Balbiani ring chains indicated that the transcriptional process was interrupted at the level of chain elongation. The highly decondensed state of active Balbiani ring chromatin, however, remained unaffected after injection of topoisomerase I antibodies. These data are consistent with the interpretation that topoisomerase I is an essential component in the transcriptional process but not in the maintenance of the decondensed state of active chromatin.


Chromosoma ◽  
1978 ◽  
Vol 66 (1) ◽  
pp. 33-44 ◽  
Author(s):  
J. -E. Edstr�m ◽  
S. Lindgren ◽  
U. L�nn ◽  
L. Rydlander

Chromosoma ◽  
1969 ◽  
Vol 28 (4) ◽  
Author(s):  
B. Daneholt ◽  
J.-E. Edstr�m ◽  
E. Egyh�zi ◽  
B. Lambert ◽  
U. Ringborg

1970 ◽  
Vol 51 (2) ◽  
pp. 327-340 ◽  
Author(s):  
U. Ringborg ◽  
B. Daneholt ◽  
J.-E. Edström ◽  
E. Egyházi ◽  
B. Lambert

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