Correlated changes in steady-state levels of Balbiani ring mRNAs and secretory polypeptides in salivary glands of Chironomus tentans

Chromosoma ◽  
1986 ◽  
Vol 94 (6) ◽  
pp. 483-491 ◽  
Author(s):  
Steven T. Case
Keyword(s):  
Steady State ◽  
Salivary Glands ◽  
Chironomus Tentans ◽  
Balbiani Ring ◽  
Steady State Levels

The 75 S RNA transcription unit in Balbiani ring 2 and its relation to chromosome structure

1978 ◽  
Vol 283 (997) ◽  
pp. 383-389 ◽  
Keyword(s):  
Salivary Glands ◽  
Functional Significance ◽  
Chromosome Structure ◽  
Transcription Unit ◽  
Chironomus Tentans ◽  
Balbiani Ring ◽  
Base Pairs ◽  
Primary Transcript ◽  
Rna Transcription ◽  
Available Information

A defined transcription unit in the Balbiani ring 2 (BR 2) region of chromosome IV in the salivary glands of Chironomus tentans has been characterized on the basis of analysis of the corresponding primary transcript, 75 S RNA, and its functional significance. The available information on the transcription unit and its relation to chromosome structure can be summarized in the following way: 1. The size of the 75 S RNA transcription unit in BR 2 is on the order of 30 000 base pairs. 2. The unit is likely to contain a long coding segment (at least 6000 base pairs), probably corresponding to information for salivary polypeptides. 3. The sequences are distributed in more than one chromomere (probably in 3-5 chromomeres). Further studies are needed before it can be stated whether or not there is a simple one-to-one relation between chromomeres and transcription units in the BR 2 region.

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.

scholarly journals The critical role of T cells in glucocorticoid-induced osteoporosis

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Lin Song ◽  
Lijuan Cao ◽  
Rui Liu ◽  
Hui Ma ◽  
Yanan Li ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Steady State ◽  
Side Effects ◽  
Critical Role ◽  
Wild Type ◽  
Receptor Activator ◽  
Steady State Levels ◽  
Induced Apoptosis

AbstractGlucocorticoids (GC) are widely used clinically, despite the presence of significant side effects, including glucocorticoid-induced osteoporosis (GIOP). While GC are believed to act directly on osteoblasts and osteoclasts to promote osteoporosis, the detailed underlying molecular mechanism of GC-induced osteoporosis is still not fully elucidated. Here, we show that lymphocytes play a pivotal role in regulating GC-induced osteoporosis. We show that GIOP could not be induced in SCID mice that lack T cells, but it could be re-established by adoptive transfer of splenic T cells from wild-type mice. As expected, T cells in the periphery are greatly reduced by GC; instead, they accumulate in the bone marrow where they are protected from GC-induced apoptosis. These bone marrow T cells in GC-treated mice express high steady-state levels of NF-κB receptor activator ligand (RANKL), which promotes the formation and maturation of osteoclasts and induces osteoporosis. Taken together, these findings reveal a critical role for T cells in GIOP.

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