Ribonucleic acid synthesis and transport in animal cells at 27 degrees C.
The failure to induce glutamine synthetase in retinal cells with hydrocortisone at 27 degrees C (37 degrees C is the normal temperature for induction) led to a study of some aspects of RNA synthesis at 27 degrees C by using the method of selective labelling with radioactive precursors, sucrose-density-gradient centrifugation and radioautography. The low-temperature treatment not only decreases the rate of RNA synthesis but also interferes with the general pattern of RNA maturation and distribution. It has been found that nuclear-cytoplasmic exchange is severely altered at low temperature and may be an explanation of the failure to induce the enzyme. When the temperature is raised from 27 degrees C to 37 degrees C, the incorporation of exogenous radioactive uridine into the RNA is distorted by a pool-dilution effect that results in an ;over-shoot' phenomenon. The kinetics of labelled uridine equilibration into the UMP pool accounts for the difficulty encountered by many investigators in ;chase' efforts with unlabelled nucleosides.
D000818:Animals; D001345:Autoradiography; D001692:Biological Transport; D002467:Cell Nucleus; D002499:Centrifugation, Density Gradient; D002642:Chick Embryo; D003593:Cytoplasm; D004790:Enzyme Induction; D005347:Fibroblasts / Q000378:metabolism; D007700:Kinetics; D008025:Ligases; D012313:RNA / Q000096:biosynthesis* / Q000378:metabolism; D012160:Retina / Q000201:enzymology / Q000378:metabolism; D013696:Temperature; D014529:Uridine / Q000378:metabolism
D012313:RNA; D008025:Ligases; D014529:Uridine