Modulation of 75S RNA synthesis in the Balbiani rings of Chironomus tentans with galactose treatment

Chromosoma ◽  
1981 ◽  
Vol 83 (5) ◽  
pp. 645-659 ◽  
Author(s):  
Louise G. Nelson ◽  
Bertil Daneholt
Keyword(s):  
Rna Synthesis ◽  
Chironomus Tentans ◽  
Balbiani Rings

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

scholarly journals Large-sized polysomes in Chironomus tentans salivary glands and their relation to Balbiani ring 75S RNA.

1977 ◽  
Vol 73 (1) ◽  
pp. 149-160 ◽  
Author(s):  
B Daneholt ◽  
K Anderson ◽  
M Fagerlind
Keyword(s):  
Salivary Glands ◽  
Messenger Rna ◽  
High Yield ◽  
Chironomus Tentans ◽  
Balbiani Ring ◽  
Rna Molecules ◽  
Large Size ◽  
Present Information ◽  
Balbiani Rings ◽  
Available Information

Polysomes from the salivary glands of Chironomus tentans were investigated to determine whether Balbiani ring 75S RNA is incorporated into polysomal structures, and thus probably acts as messenger RNA. A new extraction technique for obtaining ribonucleoproteins was applied that gives a high yield of polysomes with only moderate degradation of the cytoplasmic, high molecular weight RNA. The polysomes sedimented in a broad region (200-2,000S) with a peak value of about 700S, which suggested that they were partly of very large sizes. This was confirmed by visualization of the polysomes in the electron microscope: 400S polysomes contained mainly 11-16 ribosomes, and 1,500S polysomes about 60 ribosomes per polysome. However, polysomes containing 100 or more ribosomes were also observed. It was further established that most of the cytoplasmic 75S RNA was located in polysomes, preferentially in the most rapidly sedimenting ones. From the available information on Balbiani ring RNA in cytoplasm and the present demonstration of 75S RNA molecules in polysomes, it was concluded that at least some Balbiani ring RNA, generated as 75S RNA within the Balbiani rings, eventually enters polysomes without being measurably changed in size. The present information on the potential amino acid coding sequences in 75S RNA is discussed in relation to the large size of the polysomes observed.

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