RNA synthesis in isolated polytene nuclei from Chironomus tentans

Chromosoma ◽  
1977 ◽  
Vol 62 (3) ◽  
pp. 217-242 ◽  
Author(s):  
Horst Hameister
Keyword(s):  
Rna Synthesis ◽  
Chironomus Tentans ◽  
Polytene Nuclei

scholarly journals Demonstration of a dynamic, transcription-dependent organization of pre-mRNA splicing factors in polytene nuclei.

1996 ◽  
Vol 133 (5) ◽  
pp. 929-941 ◽  
Author(s):  
G Baurén ◽  
W Q Jiang ◽  
K Bernholm ◽  
F Gu ◽  
L Wieslander
Keyword(s):  
Mrna Splicing ◽  
Splicing Factor ◽  
Splicing Factors ◽  
Chironomus Tentans ◽  
Transcription Inhibition ◽  
Physiological Conditions ◽  
Active Gene ◽  
U2 Snrnp ◽  
Tight Linkage ◽  
Polytene Nuclei

We describe the dynamic organization of pre-mRNA splicing factors in the intact polytene nuclei of the dipteran Chironomus tentans. The snRNPs and an SR non-snRNP splicing factor are present in excess, mainly distributed throughout the interchromatin. Approximately 10% of the U2 snRNP and an SR non-snRNP splicing factor are associated with the chromosomes, highly enriched in active gene loci where they are bound to RNA. We demonstrate that the splicing factors are specifically recruited to a defined gene upon induction of transcription during physiological conditions. Concomitantly, the splicing factors leave gene loci in which transcription is turned off. We also demonstrated that upon general transcription inhibition, the splicing factors redistribute from active gene loci to the interchromatin. Our findings demonstrate the dynamic intranuclear organization of splicing factors and a tight linkage between transcription and the intranuclear organization of the splicing machinery.

RNA Synthesis in a Balbiani Ring in Chironomus tentans

1970 ◽  
Vol 35 (0) ◽  
pp. 513-519 ◽  
Author(s):  
B. Daneholt ◽  
J.-E. Edstrom ◽  
E. Egyhazi ◽  
B. Lambert ◽  
U. Ringborg
Keyword(s):  
Rna Synthesis ◽  
Chironomus Tentans ◽  
Balbiani Ring

scholarly journals Mobility restriction in vivo of the heavy ribosomal subunit in a secretory cell.

1976 ◽  
Vol 70 (3) ◽  
pp. 573-580 ◽  
Author(s):  
U Lönn ◽  
J E Edström
Keyword(s):  
Endoplasmic Reticulum ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Ribosomal Subunit ◽  
Chironomus Tentans ◽  
Salivary Gland Cells ◽  
Unique Parameter ◽  
Labeled Rna

Analysis in insect (Chironomus tentans) salivary gland cells of labeled RNA as a function of time after precursor injection and its distance to the nuclear membrane, cytoplasmic zone analysis, could previously be used to demonstrate the presence of short-lasting gradients in newly labeled ribosomal RNA. Since the gradients were sensitive to puromycin, they are likely to be a result of diffusion restriction due to an engagement of the subunits into polysomes. In the present paper the possibility was explored of recording gradients that were caused by labeled subunits in puromycin-resistant associations, which, in all probability, involve the endoplasmic reticulum. It was found that labeled 28 S and 5 S RNA but not 18 S RNA were present in radioactivity gradients lasting for at least 2 days but less than 6 days. The gradients also remained during inhibition of RNA synthesis by actinomycin, and they were completely resistant to puromycin whether given in vivo or in vitro. The semipermanent gradients formed fhere offer a unique parameter for the in vivo study of conditions for formation and maintenance of heavy subunits in puromycin-resistant bonds. An explanation for these and previous results is that the light subunit, although restricted in movement by engagement to polysomes, is nevertheless free to exchange and spread between rounds of translation, whereas at least part of the heavy subunit population is bound to the endoplasmic reticulum and less free to spread. These results offer a good in vivo correlate to previous results on in vitro exchangeability of subunits.

Chromosomal RNA synthesis in polytene chromosomes of Chironomus tentans

Chromosoma ◽  
1969 ◽  
Vol 28 (4) ◽  
Author(s):  
B. Daneholt ◽  
J.-E. Edstr�m ◽  
E. Egyh�zi ◽  
B. Lambert ◽  
U. Ringborg
Keyword(s):  
Rna Synthesis ◽  
Polytene Chromosomes ◽  
Chironomus Tentans

Rapid reformation of the thick chromosome fiber upon completion of RNA synthesis at the Balbiani ring genes in Chironomus tentans

Chromosoma ◽  
1982 ◽  
Vol 87 (1) ◽  
pp. 33-48 ◽  
Author(s):  
K. Andersson ◽  
R. M�hr ◽  
B. Bj�rkroth ◽  
B. Daneholt
Keyword(s):  
Rna Synthesis ◽  
Chironomus Tentans ◽  
Balbiani Ring ◽  
Balbiani Ring Genes

RNA synthesis in a Balbiani ring in Chironomus tentans salivary gland cells

Chromosoma ◽  
1969 ◽  
Vol 28 (4) ◽  
Author(s):  
B. Daneholt ◽  
J.-E. Edstr�m ◽  
E. Egyh�zi ◽  
B. Lambert ◽  
U. Ringborg
Keyword(s):  
Salivary Gland ◽  
Rna Synthesis ◽  
Chironomus Tentans ◽  
Balbiani Ring ◽  
Gland Cells ◽  
Salivary Gland Cells

Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

1971 ◽  
Vol 29 ◽  
pp. 548-549
Author(s):  
Awtar Krishan ◽  
Dora Hsu
Keyword(s):  
Granular Material ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Actinomycin D ◽  
Metabolic Inhibitors ◽  
Protein And Rna Synthesis ◽  
Apparent Reduction ◽  
Plant Alkaloids ◽  
In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

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