Uptake of E.coli RNA by rat liver cells in suspension

G SHANMUGAM & P M BHARGAVA

Regional Research Laboratory, Hyderabad-9, India

Published in: Indian Journal of Biochemistry, 1969, 6, 64-70.

Rat liver parenchymal cells in suspension take up Escherichia coli RNA(isolated from cells in early maximum stationary phase and containing undegraded soluble and ribosomal RNA components and presumably bulk of the messenger and 5S RNA present in the bacteria at the time of harvesting) from the incubation medium in vitro without prior degradation to acid-soluble components. At least a part of the heterologous RNA taken up is soluble or/and ribosomal RNA. The RNA taken up is distributed in nuclei or mitochondria, microsomes and cell supernatant.The uptake of Esch. coli RNA by the liver cells is initially very rapid and reaches a peak at 2.5min; after 2.5 min the degradation of the RNA taken up exceeds the uptake, with the result that at 30 min the parenchymal cells contain (in acid-precipitable form) only one-third the amount of Esch. coli RNA contained at 2·5min. The acid-soluble degradation products leak out into the medium. The heterologous RNA taken up by the parenchymal cells in suspension can also be transported back into the medium. When 2-4 x106 liver parenchymal cells are incubated with Esch. coli RNA (167-333 μg./ml), 5.5-16.2% of the RNA present in the incubation medium is taken up by the cells in 2.5 min. This represents 5.8-16.8% of the cellular RNA at the time of peak uptake at which to 106 parenchymal cells contain 4·9-13·5 μg of Esch. coli RNA. The uptake of Esch. coli RNA by the parenchymal cells in liver slices is very small when compared to that by the same cells in suspension; the RNA taken up by the slices is not degraded intracellularly.

PMID:4242575

Keywords:
Centrifugation, Density Gradient, Dactinomycin/pharmacology, Escherichia coli, In Vitro Techniques
Liver/metabolism, Microsomes, Liver/metabolism, Mitochondria, Liver/metabolism, Phosphorus Isotopes, RNA, Bacterial/metabolism

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Uptake of E.coli RNA by rat liver cells in suspension. G SHANMUGAM & P M BHARGAVA. Indian Journal of Biochemistry, 1969, 6, 64-70.

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