Ultrastructural autoradiographic analysis of RNA in isolated human lung mast cells during secretion and recovery from secretion.
BACKGROUND
Previous work has implicated isolated, control human lung mast cell granules in RNA metabolism using multiple methods of high-magnification imaging based on different mechanistic principles. These methods have demonstrated ribosomes, RNA, U1snRNP and uridine in, around and attached to secretory granules.


METHODS
Here, we have extended these studies using ultrastructural autoradiography of radiolabeled uridine incorporation in degranulating and recovering mast cells.


RESULTS
We found that control cells incorporated uridine into granules, with values that decreased dramatically in conjunction with stimulated histamine secretion and granule extrusion, and that granule stores of tritiated uridine increased together with the reconstitution of secretory granules in recovering mast cells.


CONCLUSIONS
These findings support a possible new role for secretory granules in RNA metabolism in mast cell biology.
Dvorak
A M
AM
Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Mass., USA. advorak@caregroup.harvard.edu
Morgan
E S
ES
Lichtenstein
L M
LM
Schleimer
R
R
D001345:Autoradiography; D015550:Cell Degranulation / Q000502:physiology; D003594:Cytoplasmic Granules / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D008168:Lung / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure*; D008407:Mast Cells / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure*; D008854:Microscopy, Electron; D012313:RNA / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D014316:Tritium; D014529:Uridine / Q000378:metabolism
D014316:Tritium; D012313:RNA; D014529:Uridine