Balbiani ring hnRNP substructure visualized by selective staining and electron spectroscopic imaging.
The Balbiani Rings (BR) in the polytene chromosomes of Chironomus salivary glands are intense sites of transcription. The nascent RNPs fold during transcription into 40-50-nm granules, containing in the mature transcript approximately 37-kb RNA. Using a new nucleic acid specific stain, osmium ammine B on Lowicryl sections, in combination with electron energy filtered imaging of sections containing BR granules, we demonstrate a RNA-rich particulate substructure (10-nm particle diameter; 10-12 particles per BR granule). Elemental imaging supports that these particles are enriched in phosphorus. The possible relationship of these RNA-rich particles to ribonucleosomes is discussed, as well as models for their arrangement in the mature BR granules.
Olins
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University of Tennessee-Oak Ridge Graduate School of Biomedical Sciences, Biology Division 37831-8077.
Olins
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DE
Bazett-Jones
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DP
D000818:Animals; D002683:Chironomidae / Q000648:ultrastructure*; D002875:Chromosomes / Q000648:ultrastructure*; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006651:Histocytochemistry; D008854:Microscopy, Electron / Q000379:methods; D008961:Models, Structural; D009992:Osmium; D017892:Osmium Compounds; D000644:Quaternary Ammonium Compounds; D012261:Ribonucleoproteins / Q000648:ultrastructure*; D012469:Salivary Glands / Q000648:ultrastructure*; D013052:Spectrometry, X-Ray Emission; D013194:Staining and Labeling
D034441:Heterogeneous-Nuclear Ribonucleoproteins; D017892:Osmium Compounds; D000644:Quaternary Ammonium Compounds; D012261:Ribonucleoproteins; C058639:osmium ammine B; D009992:Osmium